Most of the concerns about climate change have focused on the amount of greenhouse gases that have been released into the atmosphere.But in a new study published in Science, a group of Rutgers researchers have found that circulation of the ocean plays an equally important role in regulating the earth’s climate.
In their study, the researchers say the major cooling of Earth and continental ice build-up in the Northern Hemisphere 2.7 million years ago coincided with a shift in the circulation of the ocean – which pulls in heat and carbon dioxide in the Atlantic and moves them through the deep ocean from north to south until it’s released in the Pacific.
The ocean conveyor system, Rutgers scientists believe, changed at the same time as a major expansion in the volume of the glaciers in the northern hemisphere as well as a substantial fall in sea levels. It was the Antarctic ice, they argue, that cut off heat exchange at the ocean’s surface and forced it into deep water. They believe this caused global climate change at that time, not carbon dioxide in the atmosphere.
“We argue that it was the establishment of the modern deep ocean circulation – the ocean conveyor – about 2.7 million years ago, and not a major change in carbon dioxide concentration in the atmosphere that triggered an expansion of the ice sheets in the northern hemisphere,” says Stella Woodard, lead author and a post-doctoral researcher in the Department of Marine and Coastal Sciences. Their findings, based on ocean sediment core samples between 2.5 million to 3.3 million years old, provide scientists with a deeper understanding of the mechanisms of climate change today.
Scientists believe that the different pattern of deep ocean circulation was responsible for the elevated temperatures 3 million years ago when the carbon dioxide level in the atmosphere was arguably what it is now and the temperature was 4 degree Fahrenheit higher. They say the formation of the ocean conveyor cooled the earth and created the climate we live in now.
“Our study suggests that changes in the storage of heat in the deep ocean could be as important to climate change as other hypotheses – tectonic activity or a drop in the carbon dioxide level – and likely led to one of the major climate transitions of the past 30 million years,” says Yair Rosenthal, co-author and professor of marine and coastal sciences at Rutgers
The paper’s co-authors are Woodard, Rosenthal, Kenneth Miller and James Wright, both professors of earth and planetary sciences at Rutgers; Beverly Chiu, a Rutgers undergraduate majoring in earth and planetary sciences; and Kira Lawrence, associate professor of geology at Lafayette College in Easton, Pennsylvania.
Those computer models we keep hearing about that over-predict warming: How many ocean layers are in their grids, and how many atmospheric levels are in their grid? Just curious.
Still sacrificing their credibility on the altar of CO2, I see:
“Still, they argue that since more carbon dioxide has been released in the past 200 years than any recent period in geological history, interactions between carbon dioxide, temperature changes and precipitation, and ocean circulation will result in profound changes.”
“will result in profound changes”
Profound changes in demands for more $$$$$.
Every AGW “Climatologist” should be forced to refund Taxpayers their last 20-years of salary.
They may be right. The biosphere has been enhanced significantly. They might consider that a “profound change”.
99% of the energy in the system is in the Oceans and 99% of the greenhouse effect is because of the Oceans absorption of solar insolation. The Atmospheric energy content is a rounding error.
What a shocker to discover that on a rare planet with liquid water on its surface, oceans are important in climate change! Will scientific wonders never cease?
😎
I find this a bit odd.
Wasn’t introducing fresh water from the Arctic ice pack melting (due to man-made CO2, of course) disrupting the Gulf Stream and other ocean currents one of the original claims of pending catastrophe?
“It’s colder because it’s warmer!”
Is this an example of “recycling”?
But that’s different. It’s not natural if humans are the putative cause.
Humans are not natural don’t you know… We are the aliens in there mind. This alien has a beer filled with CO2 ready to liberate in a useful “green” gesture. Later….
I thought it was supposed to be lake agazziz or something? having a breakout..
and last I heard..I think? that same area was refilling and flooding farms n towns
somewhere up north and to the left?
Whoa … time out …
Whatever happened to settled science?
But they’re still keeping the faith … it will result in profound changes. At least the famous weasel words aren’t being used … might or could or possibly. But how do they know for a fact that any changes will be profound? Sounds more like an article of faith.
Well they have to, the paper can be about anything, but if it doesn’t say something about AGW in the abstract or the summary it’ll never get published. I could write a paper about earthworm mating habits and if the only reference to AGW is it bad for earthworm, with no supporting data, I’m golden.
But the biggest weasel words are–Climate Change.
Duh!!!!!! This is unbelievably shallow (pun intended). As they say, tell me something I don’t know. It is apparent they have done very limited literature research. Who is funding this nonsense?
You’re right – this is like rediscovering the wheel or the periodic table. There is an abundant literature on deep ocean circulation and climate. But the corrosive arrogance of the CAGW group-think has included myopic focus on atmosphere only and neglect of the literature on the deep ocean and THC (thermo haline circulation).
This paper is at least a step (back) in the right direction.
Precisely, this is what happens with group-think and why it’s so dangerous and why NO credible scientific organization should threaten a member with expulsion for not believing a current popular hypothesis.
This is how modern day Climate Science intends on slowly walking back the monumental mistakes of the last 20 years. One paper at a time.
The ocean conveyor illustration has the worm and cold currents locations in the N. Atlantic transposed. Warm current flows north on the European side, while the cold current flows southward along the N. American coastline.
Some of ideas how the N. Atlantic currents affect the ocean conveyor flow can be seen here
link: HERE
Current status of the Gulf Stream.
http://oi62.tinypic.com/11v17xk.jpg
Now we’ll have to do away with all propeller-driven ships because their backwash (computer models say) are causing the changes in ocean currents and thus causing global warming.
Humans just have to feel in control, you know?
Rookie here, and not a scientist. Trying to learn about CC.
Could/would an event such as the eruption of the Yellowstone caldera/volcano (or equivalent) some 600,000 years ago produce enough CO2 to have impacted climate then? I realize there were particulates in addition to gasses. It’s just something I thought I would be interesting to play with and compare with CO2 rates of today for example. I could find reasonable historic charts for the temps part, but not sure how to go about the eruption and CO2 part.
Two fold thinking. It might help disprove CO2’s impact, but it also might support it for that age if in massive quantities. Please don’t rain down on me for the thinking. I’m not using “code” for being GW/AGW. Just the opposite, I’m a believer in the benefit side.
I just don’t know how to go about it so hoping for a teacher.
Not claiming to be a “teacher” but if Yellowstone blew, we’d have more to concerned about than it’s added CO2 heating things up.
Didn’t Krakatoa produce “the year without a summer”? (Which, indirectly, gave us Mary Shelley’s “Frankenstein”.)
Hi Gunga,
Think it would certainly be a bad day at the office.
I meant when it did last time. Sorry if not clear. And I have to believe the particulates would have been an impact leading toward cooling. Just thought It’d be interesting to look at and I’m sure someone has.
No – and I can say that with some certainty.
Not Krakatoa, but Tambora.
Thanks for the correction.
Danny, a partial reply to your thoughtful question. Some of the Antarctic ice and sediment cores go back this far (e.g. Andrill). Their temporal resolution at such an extreme age is quite poor.. But there is little evidence that the eruption of the Yellowstone supercaldera had a noticable lasting effect (like coinciding with a deglaciation onset– those generally coincide with Milankovich cycles of Earths orbital eccentricities.)
Of course we know from Tambora, Krakatoa, and Pinatubo that there must have been a significant transitory effect for the Yellowstone event. Evidence suggests likely more on the transitory aerosol cooling side. But those sort of subdecadal changes get lost in ice core noise at that long ago time.
Rud,
Thanks for that. Now I have a place from which to start looking.
Great questions. I think the whole subject of volcanos deserves much more discussion in the climate context. For example, Bardarbunga is ready to blow (maybe) in Iceland right now. When Laki blew in 1783, it reportedly produced “A Pinatubo’s worth of ash every three days.” And continued for six months. Reportedly, six million people died in Europe from the resulting famines and sulpher dioxide poisoning. At mid day, the sun in England was “A dull red orb.”
IMHO, Volcanos, along with solar flares and a few other things, being completely unpredictable and unstoppable, pose a larger threat to humanity than the “possibility” of long term damage from CO2.
yes todays and yesterdays activity has soared in high range quakes, very much over the last few weeks of simmering with the odd high 4 n 5
For CC the best place to start is the subject of the above paper – the oceans. They hold 99% of climate energy and really call the shots regarding climate. Weather comes from the atmosphere, climate from the ocean.
Volcanos do affect weather but their effect is transient as others have commented. Volcanic events have to reach a gigantic scale such as an Indian / Siberian flood basalt or a Chixilub Gulf of Mexico dinosaur-terminating asteroid impact, to register an effect on ocean circulation.
The Rutgers paper correctly points to a change in deep ocean circulation 2.7 million years ago as leading the descent into the current Pleistocene glacial period. Interestingly large whales evolved around the same time – on about the same timescale as humans. The BBC show their shallow naivety on science by suggesting in a current article that it was the extinction of the giant megalodon shark that allowed whales to grow bigger. That’s not how ecosystems work – predators are beneficial and don’t stop herbivores evolving. But what caused the whales to grow big was the same increase in deep ocean circulation which started the Pleistocene glacial period. This deep circulation increases upwelling of essential nutrients from deep water to the surface which made the oceans more biologically productive and created for instance the vast shoals of Antarctic krill, which the baleen whales evolved to feed on.
“Weather comes from the atmosphere, climate from the ocean.”
Now that’s something I can chew on. Interesting perspective. Thanks for that!
I’d read that climate involves atmosphere, vegetation, and land mass, but don’t recall water (oceans) being a part of that definition. I can somewhat see how it’s an “engine” but help me here, are you indicating it’s the entire vehicle?
Appreciate some guidance on your thinking, but I made C’s in chemistry, botany I did well, and zoology was a working B, Geology was a B too, but intro to. They weren’t part of my major but I enjoyed them. And it was a looooong time ago. Sharing all this so you’ll know to speak with me as an infant (maybe a bit more mature than that) in this CC discussion.
Earth is a water planet. Its climate is largely about the hydrological cycle, ie water as gas & liquid in the air, liquid in the oceans & on land, & solid ice mostly on land but also sea & a bit in the air.
During Ice House intervals in our planet’s climate, ice exists in larger or smaller amounts. When, as in the present Cenozoic Ice Age, but also in the Carboniferous-Permian & Ordovician Ice Ages, massive ice sheets cover continents, sea level is necessarily lowered, as oceans of ice spread over the land. This was even more extreme during the Snowball Earth episodes of the Pre-Cambrian, when land & sea ice reached low latitudes, possibly to the equator.
When it’s very cold, water also comes out of the air.
This study is another one if those which blithely move ocean currents around to get whatever they wish. It does not work that way.
dO18 records show that the ice age was a gradual decline in temp. , worldwide, starting way back in the early Pliocene.This paper has the ice age confined to the NH. Not so. More invention palmed off as science.
There was already an ice age in the SH, kicked off as well by changes in ocean circulation, when Antarctica was separated from Australia & South America deep channels, c. 38 million years ago.
Fuzzy language means fuzzy brains. The co-authors say that CO2 was “pulled” into Atlantic waters! along with heat! and circulated to the Pacific where it was released.Such inventiveness. Hard to know where to begin with this nonsense.
I wonder how much this one cost me.
You probably don’t want to know.
But the authors couldn’t have gotten your tax dollars without working CO2 into the story somehow.
Say the magic word CO2 & win a grant!
Milodonharlani:
The previous ice age began with the Oligocene 33.7 million years ago. It lasted about 12 my. It coincides with the Oligocene and ended abruptly. Sea levels fell some 150 feet and then rose back at the start of the Miocene. There has since been no ice age in the SH until the Pleistocene when the present ice age started. Do not confuse polar ice with ice age.
A massive ice sheet on Antarctic is more than “polar ice”. It’s an ice age. It did not go away in the Miocene. The EAIS did fluctuate in size during the Miocene, but it never went away. Earth has been in ice house mode since the Oligocene, as it was in the Late Carboniferous & Early Permian. The ice house got colder once the Isthmus of Panama closed. The ice house started because of high latitude ocean currents & got worse because low latitude circulation changes.
Since ice houses seem to occur at about 150 million year intervals, there may be cosmic influences as well as tectonic ones.
Milodonharlani:
Concerning the Antarctic ice sheet, that is a geographic feature and of course it preceded the Pleistocene. I think that positing a SH ice age on this basis is a stretch. Thermal isolation of the south pole by the continent is the operative factor for the ice there, not any “ice age” in the Pleistocene sense.
You might be a little fuzzy on geologic terminology.
An Ice House is an interval in earth history during which ice is present in more extensive glaciers & ice sheets. During a Hot House, the planet is totally or largely ice-free.
During the Mesozoic, for instance, earth experienced an Ice House, without suffering an Ice Age, which requires extensive ice sheets, not just montane glaciers. But there were two Ice Ages during the Ice Houses of the Paleozoic (at least), & has been an Ice Age during the Ice House of the Cenozoic. We’re in the midst of it now.
Conditions in the Mesozoic weren’t ripe for a full-on Ice Age.
During the current, Cenozoic Ice House, ice sheets formed on Antarctica during the Oligocene, then waxed & waned during the Miocene, but the Ice Age continued, since the EAIS never melted completely. You can consider the Pleistocene & Holocene Ice Age separate from the Oligocene-Miocene-Pliocene Ice Age, with only SH ice sheets, if you want, but why?
I would say that the Ice House and the Hot House terminology belongs in the Outhouse. Call that fuzzy if you like, but characterization of the Mesozoic as an Icehouse sounds wondrously strange.
The Antarctic ice sheet is purely geographical. The presence of a polar ice sheet does not by itself mean an iceage, imo.
I didn’t say that the Mesozoic was an Ice House. Quite the opposite. It would help if you read & understood what I actually wrote. There was an interval even in the generally warm Mesozoic Hot House in which ice formed in certain parts of the globe. Some have connected this cooling period with the rapid evolution of feathers. But the arrangement of continents & other conditions kept an Ice Age from forming during this cool interval.
You may think the concept belongs in the outhouse, but climatologists don’t. A number of Ice Houses have been identified, occurring at surprisingly regular intervals. They were more severe back when the sun was less powerful, leading to the Snowball Earth events of the Pre-Cambrian.
The Phanerozoic Ice Houses with Ice Ages were the Ordovician/Silurian, the Carboniferous/Permian & the present one, which began with ice sheet formation on Antarctica, thanks to its isolation by the Southern Ocean. This Ice Age extended to the NH during the Pleistocene, most likely because of another rearrangement of ocean currents due to the connection of the Americas.
Please state what makes you think that this well-supported scenario is bogus, besides one laughable paper (which didn’t say what you claimed it did) by a Smithsonian employee, two of whose other papers were on climate change & the first described a Paleocene crocodylomorph from NE Colombia?
Thanks.
Maybe a visual aid would help you:
http://www.scotese.com/climate.htm
You move the ocean currents about like the authors of the study that is the subject of this post. That is the first problem.This is what is meant by the term “arm waving”. Your poor arms.
The second problem is that you cannot distinguish between a polar ice sheet and an actual Ice Age, which by definition is the Pleistocene, which definition seems to have been omitted from your education.
The third problem is that you have invoked the cosmos as some influence on earth’s climate. I don’t believe in astrology.
Fourthly, you obviously are not capable of assimilating new observations on the matter and such a handicap does not lead to confidence. Instead you wave your poor arm about and evoking ice houses from the Phanerozoic and finally a snowball earth. You sound like a reborn Carl Sagan.
I don’t know why this is hard for you to understand. The Pleistocene is an Ice Age, not the only Ice Age.
The posited cosmic influence on ice ages is passage through the galactic spiral arms, which affects GCR flux, hence cloudiness. Had you studied climatology, you’d have read about this hypothesis.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CCYQFjAB&url=http%3A%2F%2Fiopscience.iop.org%2F0004-637X%2F626%2F2%2F844%2Fpdf%2F61945.web.pdf&ei=BSVLVMTzFYjfyASE_YLIBg&usg=AFQjCNHd3pw28VlPAnFjnUrc6Vdj2NXJSQ&sig2=CQYrnqzxM0vJvq_FO_247A&bvm=bv.77880786,d.aWw
You have nothing new to contribute. If you did, I’d consider it. The only arm waving is yours. Please offer even a shred of evidence to support your counterfactual assertion that all oceanic circulation is from the equator to the poles. So far that claim is just as evidence free as your nonsense about the Isthmus of Panama.
I don’t know why I’m wasting my time trying to educate you, but for a start on elementary oceanography, please read this:
http://en.wikipedia.org/wiki/Boundary_current
Since your ignorance of geologic history appears complete, here is some information on prior ice ages in the Phanerozoic. You’d already know about them had you bothered to look at the visual aid I linked earlier:
http://hockeyschtick.blogspot.com/2014/04/new-paper-studies-ordovician-ice-age.html
http://www.oberlin.edu/Geopage/projects/204projects/jones/Permo-Carboniferous_and_Ic.html
After you’ve educated yourself, get back to me.
Now what is this about the whirling milky way determining Ice Houses and Hot Houses and weaker suns and ice ball earths and warm currents that move, not poleward, but wherever the fancy sends it? And the isthmus of Panama causes continental glaciation because there is more water vapor in the NH?
You have quite a mix there, my friend, a regular climate sampler, but I believe I’ll pass, thank you.
milodonharlani
October 24, 2014 at 7:49 pm
Shaviv’s idea of the ice house periods apparent 150 million year spacing being linked to the similar time scale of galactic arm orbit, would require there to be another ice house/age at the Jurassic/Cretaceous boundary (150 mYa). What happened at that time? – I recall there was cooling and some glaciation.
phlogiston
October 25, 2014 at 12:44 am
The findings of Shaviv & other cosmoclimatologists that ice house occur at about150 million year intervals does indeed require a Mesozoic cold snap, as I’ve written about in this thread already.
You recall correctly that there was cooling & some glaciation around the Jurassic/Cretaceous boundary. A full-on ice age did not develop then presumably because there was not enough land near the poles & the oceans remained warm. Antarctica was farther north then than now, & of course still largely attached to Gondwanaland.
Greymouser:
Carlos Jaramillo has a PhD in Geology and botany and works with the Smithsonian Tropical Research Institute of Panama. He has published two papers this year of interest: one study reports fossil wood of the Malvaceae family from the Cucaracha Formation, exposed in Culebra Cut, I believe. These he dates as lower Miocene (over 20 my). The other study identifies fruit from Juglandidae (walnut family) from Panama, Also dated to lower Miocene.
It is conclusive that the isthmus was forming over twenty million years ago.
I believe that further investigation will establish a date in the Eocene for the first emergence of the isthmus, or 40 mya or more.
Milodonharlani:
Please do not make false attributions to me. I stated that _warm_ currents flowed poleward as part of the thermodynamics of the oceans. I never stated that all currents flowed poleward, as you have me saying.
Do not bother with links because I regard the isthmian theory of the ice age as prima facie erroneous.
See my response to greymouser above.I expect that the isthmian hypothesis will eventually be discarded as more stratigraphy of that area is studied and dated.
It appears that you have not read, or if read, failed to understand, the paper I assume you cite.
You may download the relevant papers at this site. Please note that Jaramillo is not the main author of either:
http://www.stri.si.edu/sites/publications/results.php?scientist=Carlos+A.+Jaramillo
Rodriguez-Reyes, O., Falcon-Lang, H. J., Gasson, P., Collinson, M. E., and Jaramillo, C., 2014, Fossil woods (Malvaceae) from the lower Miocene (early to mid-Burdigalian) part of the Cucaracha Formation of Panama (Central America) and their biogeographic implications: Review of Palaeobotany and Palynology, v. 209, p. 11-34.
Sepulchre, P., Arsouze, T., Donnadieu, Y., Dutay, J.-C., Jaramillo, C., Le Bras, J., Martin, E., Montes, C., and Waite, A. J., 2014, Consequences of shoaling of the Central American Seaway determined from modeling Nd isotopes: Paleoceanography, v. 29. DOI 10.1002/2013PA002501
Neither says what you imagine it does. As I tried to get you to understand, the Central American Seaway shoaled for millions of years before it became shallow enough to block the exchange of Pacific & Atlantic waters & rearrange currents.
A fossil log suggests that islands existed in the Seaway, which, was already known from the interchange of species between in the continents, in the first link I provided for you, which it seems you still haven’t read.
Rodriquez, et al, conclude that, “The occurrence of trees of South American affinity in the lower Miocene of Panama is of palaeogeographic significance, suggesting the existence of plant migrations between South America and the
Panama Isthmus as early as the Miocene.”
As I have previously pointed out, the intercontinental exchange began before the Pleistocene for species capable of drifting or island-hopping. Again as I told you, seed pods of many plants are capable of drifting very long distances in saltwater, so the short journeys involved in the Miocene & Pliocene Seaway are not in the least surprising & say nothing about ocean currents through it.
The authors of these studies agree with prior evidence, not with your baseless fantasy. The Seaway was not closed ten million years ago, as you so falsely imagine, but was still hundreds of meters deep (enough for Altantic & Pacific currents to run through it), according to their model & simulations:
Consequences of shoaling of the Central American Seaway determined from modeling Nd isotopes
P. Sepulchre1, T. Arsouze1,2, Y. Donnadieu1, J.-C. Dutay1, C. Jaramillo3, J. Le Bras1, E. Martin4,
C. Montes5, and A. J. Waite4
1Laboratoire des Sciences du Climat et de l’Environnement, CNRS-CEA-Université de Versailles Saint Quentin en Yvelines,
Gif-sur-Yvette, France, 2Now at Ecole Nationale Supérieure de Techniques Avancées, UME, Palaiseau, France, 3Smithsonian
Tropical Research Institute, Ancón, Panama, 4Department of Geological Sciences, University of Florida, Gainesville, Florida,
USA, 5Geociencias, Universidad de los Andes, Bogotá, Colombia
The Central American Seaway played a pivotal role in shaping global climate throughout the late Cenozoic. Recent geological surveys have provided new constraints on timing of the seaway shoaling, while neodymium isotopic (εNd) data measured on fossil teeth, debris, and ferromanganese crusts have helped define the history of watermasses in the region. Here we provide the first 3-D simulations of εNd responses to the shoaling seaway.
Our model suggests that a narrow and shallow seaway is sufficient to affect interoceanic circulation, that inflow/outflow balance between the Caribbean and the Antilles responds nonlinearly to sill depth, and that a seaway narrower than 400km is consistent with an active Atlantic meridional overturning circulation during the late Miocene. Simulated εNd values in the Caribbean confirm that inputs from radiogenic Pacific waters in the Caribbean decrease as the seaway shoals. Despite model limitations, a comparison between our results and εNd values recorded in the Caribbean helps constrain the depth of the Central American Seaway through time, and we infer that a depth between 50 and 200m could have been reached 10Ma ago.
As for your imaginary planet in which warm currents only go toward the poles, please explain then the oceanic gyres today, let alone the convincing if not indeed incontrovertible evidence of east-west currents in past arrangements of the continents, as I’ve mentioned before.
A glance at a globe with winds & currents marked should have disabused you of this fantasy. For instance, the Equatorial Counter-Current, Kuroshio & Gulf Stream go east, although an off shoot of the latter, the North Atlantic Drift, does head north. The North & South Equatorial Currents go west.
I would urge you to study oceanography before presuming to comment upon it.
greymouser70
October 25, 2014 at 5:40 pm
Thanks for your succinct insertion of sanity & reality.
Contrary to Mpainter’s delusion that recent studies show the CAS closed by 10 million years ago, Woods Hole just last year reposted this analysis from 2004, with interactive graphics, of how the rise of the Isthmus finally shut off exchange of Atlantic & Pacific waters across the Seaway:
http://www.whoi.edu/oceanus/viewArticle.do?id=2508
The Miocene to Pleistocene geologic development of the region is pretty well known.
Milodonharlani:
The paleobotanical evidence is conclusive. The isthmus was building before the Miocene. Malvaceae and Juglandeae are not island hopping plants. Whether there was communication between the two oceans at this time is immaterial and does not matter, because the isthmian theory of the ice age fails prima facie, for reasons that I have given in other comments, which reasons you studiously fail to address while you lecture me about ocean currents in an uninformed manner.
mpainter
October 25, 2014 at 6:51 pm
The “paleobotanical evidence” is not only not conclusive, but doesn’t even begin to suggest what you’ve tried to torture out of it, as the authors of the very papers you cite state. Again, please read them.
When are you going to learn to do the least little bit of research before making preposterously false assertions? Malvaceae most certainly is an island-hopping family, which you might have known had you ever studied botany:
“Experimental hybridization and chromosome pairing in Kosteletzkya (Malvaceae, Malvoideae, Hibisceae), and possible implications for phylogeny and phytogeography in the genus
“Orland J. Blanchard 1, Jr. 1
1 University of Florida Herbarium, Florida Museum of Natural History, 379 Dickinson Hall, P. O. Box 110575, Gainesville, Florida 32611-0575, U.S.A.
“Dispersal over considerable distances appears to have been accomplished by several Kosteletzkya species. Known contemporary distributions suggest that Kosteletzkya adoensis has jumped from the African mainland to Madagascar, which is a minimum of 800 miles from the nearest known mainland population. It also appears to have dispersed westward from its main center in East Africa to the mountains of Cameroon (1100 miles) and the mountains of Sierra Leone (a further 1350 miles), with no known occurrences of the species—and no montane habitats—in the intervening areas. Kosteletzkya begoniifolia has made a similar jump from montane East Africa to Cameroon (1050 miles), and Kosteletzkya borkouana has dispersed from eastern Democratic Republic of the Congo and East Africa 1300 miles across a considerable expanse of the Sahara to the Borkou region of northern Chad (Blanchard 2013). In the New World, Kosteletzkya depressa has spread to the Cayman Islands and throughout the Greater Antilles, presumably from a mainland source (see Howard 1973), and Kosteletzkya pentacarpos has spread from the United States to Cuba and Bermuda. Moreover, if the latter turns out not to have been transported to Eurasia by human agency, it must have made the trans-Atlantic trip by long-distance dispersal, as did the carrier of the ancestral B-genome, but in this case dispersing from west to east.”
As for the Juglandaceae (as its spelled), please explain how members of the family got to islands that have always been islands, such as in the Caribbean, without hopping? Thanks.
You have given no other reasons in prior comments, so how could I studiously avoid them? I have replied to all your alleged “reasons”, showing them completely unfounded. If you think I missed some, please state them.
The Equatorial & Equatorial Counter Currents, among others, show your counterfactual, baseless assertion that warm currents always go toward the poles to be wildly ridiculous. The existence of the North EC & ECC (often called North ECC) today also demonstrate your unsupported claim that currents couldn’t have flowed between the Atlantic & Pacific in the northern tropics during the Miocene & Pliocene to be absurd. The flow east & west in the latitude of the Central American Seaway now, interrupted only by the Isthmus of Panama & adjoining continents, so nothing would have stopped them from going through it then.
I’d strongly urge you to quit digging deeper the hole you’re already in.
Milodonharlani:
I see that you finally agree that the Panamanian Isthmus was emerging prior to the Miocene. (I think.Whew!)
Let us return to the original topic: whether or not the formation of the isthmus of Panama led to the Pleistocene.
I reject that hypothesis prima facie for reasons that I have already given. I repeat those here:
1. Most obviously, we are are in an interglacial. The isthmian closure remains, but where are the continental glaciers that you claim are the inevitable result of that condition? In short, your isthmian hypothesis fails because it does not and cannot explain interglacials. Do you see the problem?An explanation of the ice age which ignores interglacials is not worth considering IMO.
2. Another reason for prima facie rejection of the isthmian hypothesis
Is the restricted effect of the posited circulation change of the North Atlantic, which change is claimed to have initiated the Pleistocene (the ice age).
Such change would have been confined to a fraction of the NH, and thus does not, cannot explain the ice age. The ice age was worldwide, as the cooling was worldwide, and the warming of the interglacial was worldwide.
3. A third reason for prima facie rejection of the isthmian hypothesis comes from ice cores. The posited increase in precipitation (as snow) due to circulation changes in the N Atlantic is claimed to be the cause of continental glaciation, but the Greenland ice cores show that the onset of the interglacials _doubled_ NH precipitation, and then return of glaciation brought dryer conditions and half the rate of interglacial precipitation.
This consideration of actual precipitation versus posited precipitation refutes the isthmian hypothesis conclusively, for as we see, doubling of precipitation is associated with the retreat and disappearance of continental glaciers and not with their growth.
Anyone who can see fault in my above reasons for rejection of the isthmian hypothesis
mpainter
October 26, 2014 at 2:40 am
It appears that I have to teach you everything relevant to the Central American Seaway & glaciations.
I didn’t “finally agree” on when the Isthmus “was emerging”. Had you bothered to read what I actually wrote many comments ago, you’d know that I said of course the formation of the Isthmus took millions of years. But the issue is when that process led to the shut off of currents through the Seaway. That didn’t happen until after three million years ago.
1) It is preposterous to assert that the “Isthmian” hypothesis fails because of interglacials, which occur primarily because of Milankovitch Cycles. But even during interglacials, the Ice Age remains in effect. There is an ice sheet on Greenland & more extensive montane glaciers than in the Pliocene, before the closure of the CAS.
2) Clearly you have not bothered to read a single one of the many links I’ve provided for your education. The closure increased the strength of the Gulf Stream greatly, leading to the formation of ice sheets. Try starting with the Woods Hole article, which explains the process well.
3) Greenland ice cores don’t go back 2.7 million years. Precipitation changes between glacial & interglacial intervals say nothing at all about the initiation of NH ice sheets in the first place. It’s no surprise that colder periods are drier then warmer ones over the Greenland ice sheet. What got the Greenland, North American & Eurasian ice sheets going in the first place however was greater precipitation at higher latitudes than during the Pliocene.
If you were willing actually to think about it, I’m sure you could understand how that works. If you can’t, then please read the Woods Hole explanation of how it worked, based upon actual physical evidence. Your crazy conjecture is completely lacking in evidence & runs contrary to all available observations, as I’ve repeatedly shown.
At least you’ve finally shut up about your absurd claims that plant families you mentioned don’t island hop. But I’m afraid you’re impervious to evidence, since your mind is made up against reality, for whatever inexplicable reason.
If, as you assert, “Anyone who can see fault in my above reasons for rejection of the isthmian hypothesis,” then why have you been unable to convince a single reader here of the validity of your unsupported claims?
mpainter: There is no evidence that there was an “ice age” in Antarctica! There is however good evidence that with the opening of the Drake Passage and the Tasmanian Passage about 35 mya led to an intensification and completion of the Circum-Antarctic Current. You say that there could not be current flow from the Pacific to the Atlantic.Consider this, The surface of the Pacific ocean is about 20 ft higher than the Atlantic ocean. The proto-Gulf Stream current was in existance at that time (approx 3.5 mya). Closure of the isthmus began about 5 mya. I note that Jaramillo cites a log dated at over 10 mya found in the excavation for the new canal. How firm is that date and what dating technique was used? At present his hypothesis is still very much speculative and there is no general agreement that he is right. You might want to check out what Woods Hole Oceanographic Institute has to say about it.
http://www.whoi.edu/oceanus/feature/how-the-isthmus-of-panama-put-ice-in-the-arctic
A slight correction.. The Pacific Ocean is approx 20 cm higher than the Atlantic.
Mpainter’s suggestion that currents only flow towards the poles is ludicrous.
The mighty, frigid Humboldt Current carries cold water from Antarctica to the equator, making the coast of Chile where I live half the year often foggy. The Galapagos penguin exists because of the Humboldt, which forms the eastern portion of the South Pacific Gyre (one of five such ocean gyres).
The comparable broad, north-flowing (equatorward) cold current in the Atlantic is the Benguela Current, which forms the eastern portion of the South Atlantic Gyre.
During other arrangements of the continents, earth-circling currents have existed in the tropics. When the Central American Seaway was open in the Pliocene, before c. three million years ago, water flowed from the Atlantic to the Pacific. The biological, geologic & oceanographic evidence in support of this observation is, as I said, overwhelming.
mpainter: The isthmus of Panama may have been forming 40 mya but it definitely did not close until 2.7 mya . Until that time the Central American Seaway was still in existence. Pale-oceanographic reconstructions show that most of Central America was a shallow shelf or scattered islands. The Gulf Stream starts in the Atlantic near the equator and the Proto-Gulf Stream was already there in the Miocene. It was carrying warm water northward but not nearly as much as today. There are notable differences in Salinity and fossil assemblages on either side of the isthmus at the same time. All indications are that some of the proto-Gulf Stream waters did flow into the Pacific and vice-versa. After the isthmus closed then the north-south circulation pattern that we see today was established. You are entitled to your opinion but I am not convinced..
Anyone not blinded by CACA gaseousness already knew that changes in ocean circulation caused by the Isthmus of Panama initiated NH glaciation at the onset of the Pleistocene.
“changes in ocean circulation caused by the Isthmus of Panama”
Wait for it. Changes in “ocean circulation”, that have resulted in “Global Warming” will be blamed on man — building Panama Canal.
Plus, think of all the evil CO2 emitted by Roosevelt’s steam shovels, & all that poor innocent tropical vegetation mercilessly slaughtered by the Yankee imperialist climate criminals!
OH NO!
What will Obama do? Carter gave the Panama Canal to Panama. (Actually, he paid them to take it.) So now US coal plants are off the hook?
More misinformation. The isthmus of Panama has nothing to do with the Pleistocene. That is just more ocean circulation baloney.
I’ll assume you’re serious.
You are free to believe that the closure of the Isthmus had nothing to do with Pleistocene, but the fact is that after the Americas were connected ocean currents necessarily changed, & at least coincidentally NH glaciation began. There are plausible physical mechanisms to explain causation behind this correlation.
Given the evidence in favor of this hypothesis, I’d like to see why you believe that the changes in tropical oceanic circulation the closure caused would or could not have led to NH glaciation.
Quite serious. Your “evidence” has been superceded by new data. The Isthmus is at least ten million years old, according to several studies of the last two or three years. The isthmus could not have started the Pleistocene.
Since you have yet to offer any evidence that the Isthmus didn’t rearrange circulation c. 3 Mya, I’ll stick with what I’ve read & seen myself.
Is this study recent enough for you?
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2987556/
J Mamm Evol. Dec 2010; 17(4): 245–264.
Published online Jul 14, 2010. doi: 10.1007/s10914-010-9144-8
PMCID: PMC2987556
The Great American Biotic Interchange: Dispersals, Tectonics, Climate, Sea Level and Holding Pens
Michael O. Woodburne corresponding author
Of course the collisions of tectonic plates that caused the Central American uplift didn’t happen all at once. It occurred over millions of years. But around the onset of the Pleistocene circulation between the Americas was effectively shut down. If you have evidence against this conclusion, please present it.
Interchange of species between North & South America also occurred over millions of years, as the the water shoaled & islands emerged. Then, during the Pleistocene, lowered sea level allowed new interchange pulses.
Is 2009 also too ancient?
http://geology.gsapubs.org/content/37/10/959.full
From the warm Pliocene to the cold Pleistocene: A tale of two oceans
Gabriel M. Filippelli1 and
José-Abel Flores2
Just as it took millions of years for deep channels to form cutting Antarctica off from Australia & South America, so the formation of a land bridge between the Americas took time. But its effect on ocean circulation was more abrupt.
The studies of Carlos Jaramillo date from 2010 to present. He has numerous lines of evidence that show the isthmus is over ten million years old. He is a geologist with the Smithsonian Institute. His studies are on the web. The evidence is very convincing.
The fact that Jaramillo works for the Smithsonian should have been an immediate tipoff.
But you’re mistaken, he argues not for a 10 million year old isthmus, but “early Oligocene to early Miocene”! Mind you, this is based upon modelling the phylogeny of palm tree taxa. As you may be aware, palm seeds can disperse across saltwater by drifting on currents, as the distribution of palm trees on oceanic islands ought to suggest. Besides which “clocks” as opposed to “rocks” is itself a contentious issue in both biology & geology.
http://onlinelibrary.wiley.com/doi/10.1111/j.1095-8339.2012.01281.x/abstract
There is a huge industry in the USA today aimed at disparaging any explanation for climate change other than CO2. The Smithsonian is at the cutting edge of this corrupt enterprise. Don’t get me started on my brother’s war with them over their WWII exhibits.
Sorry, but you’ll have to do better than this to convince me that 1) oceanic currents were not changed around the Pliocene/Pleistocene boundary by the final effective closure of the Central American Seaway, & 2) that this rearrangement led to NH glaciation.
I am not trying to convince you since your mind is closed. But for the sake of others I comment on this. Circulation of warm water is from the tropics poleward. Tropical Atlantic waters would naturally have circulated toward the Arctic Ocean, isthmus at Panama or not. This circulation is governed by sinking polar waters, isthmus or no.
You have your reply at 6:54. My post was 6:38. That is sixteen minutes. Such a fast reader you are to have considered the evidence put forth by Jamarillo and then compose your response, complete with links!. And I dont see what your dislike of the Smithsonian has to do with the issue. Your attribution of motive to Jaramillo is far-fetched, IMO.
I read rapidly & am familiar with the literature. My mind is open. You just haven’t produced anything to change it.
Your assertion about currents is simply wrong as wrong can be, as you’d know had you ever studied oceanography or earth history. The arrangement of continents influences surface currents. I would have thought that this to be obvious.
For instance, during the Early Cretaceous, with a planet-circling tropical sea, the Tethys, lying between two supercontinents, Laurasia & Gondwana, ocean currents ran radically differently from now.
If any one reading your comments is convinced by them, I’d like to know why. Maybe if you could produce even a single shred of plausible evidence.
The “new” theory is based on the appearance of palm trees in South Americas. Computer models AND observations show that a narrow body of water with sufficient depth can serve as an efficient conduit for large ocean currents. Therefore the palm tree data doesn´t really mean there´s a conflict.
I love to see new theories and ideas being floated, therefore I´m not necessarily opposed to the idea that the isthmus may be older. However, the new theory has been postulated ignoring the enormous amount of data which backs the younger age (ca 3 million years). Therefore to bring this up as “misinformation” reveals a very dogmatic, nearly religious approach towards science. This approach involves accepting ANYTHING which fits your preconception and supports your political stance, and trashing whatever doesn´t fit as “misinformation”. It´s not a very rational approach, and it makes you lose credibility.
I will stand on this statement:
More misinformation. The isthmus of Panama has nothing to do with the Pleistocene. That is just more ocean circulation baloney.
Above, I meant that the isthmian hypothesis of the initiation of the ice age does not deserve serious consideration.
Please spare me your pontifical sermonizing.
The onset of the Pleistocene needs to be re-thought.
On what basis? A single paper by Jaramillo on modeling palm family phylogeny? YHGTBSM!
You don’t need to resort to phylogenetic modeling to date the closure of the former “Straits of Panama”. Every line of actual physical evidence leads to the same conclusion. The dating of the interchange of species needing a continuous land bridge to move from North to South America & the reverse confirms it. More importantly, the actual geology & oceanography confirm it. Please see the papers I cited, plus dozens if not hundreds of others.
That the rearrangement of ocean currents led to more moisture in the north, producing ice sheets also supports this date.
Where did you get the idea that the isthmus was a fully functioning land bridge ten million years ago? The one paper by the guy you cited as your up to date authority said tens of millions of years ago,which is blatant nonsense.
If the Isthmus of Panama is 10 million years old, what kept animals from using it for 7 million years?
mpainter @ October 24, 2014 at 6:55 pm
It appears that you have confused recent attempts to reconstruct the details of the development of the Central American Seaway, an ongoing area of multidisciplinary research, with an imagined revolution in our understanding of Miocene, Pliocene and Pleistocene geology. No such revolution has occurred, hence the onset of the Pleistocene does not need to be rethought. That’s not to say that we aren’t still investigating it, just as science is still improving its understanding of the theory of gravity.
Had you studied this topic, maybe this confusion on your part could have been avoided. None of the researchers whom you’ve cited share your faith-based belief in the Miocene closure of the Seaway. It’s a pity you didn’t read their actual papers before taking their names in vain.
It’s well known and indeed should be obvious that the tectonic events leading to the closure occurred over millions of years. What remains conjectural or controversial, awaiting further evidence, is the precise geographical configuration of the Seaway during the late Miocene and Pliocene. For that matter, it might have been intermittently open during the Pleistocene:
http://www.academia.edu/400648/The_closure_history_of_the_Panama_Isthmus_Evidence_from_isotopes_and_fossils_to_models_and_molecules
The closure history of the Central American seaway: evidence from isotopes and fossils to models and molecules
D. N. SCHMIDT
Department of Earth Sciences, University of Bristol, Wills Memorial Building, Bristol, BS8 1RJ
“Interestingly, several species point towards geneflow even in the Pleistocene which has been inter-preted as evidence for breaching of the PanamaIsthmus. Evidence from planktic foraminifers (Cronin & Dowsett 1996) points towards two breaching events during high sea-level stands, the most recent occurring at 2 Ma. Keller et al. (1989) also suggested the existence of seawater connections between the Caribbean and eastern Pacificthat lasted until 1.8 Ma, based on foraminiferal data. A short-lived breach of the Isthmus wouldbe expected to affect a small number of species,which (because of their ecological attributes ordue to pure chance) either re-established genetic connections with their geminates, or replaced the resident population.”
I strongly urge you to read Schmidt’s paper. It surveys our understanding of the history of the Seaway up to 2007. Perhaps then you’ll appreciate the context of the bits and pieces you’ve read published since then. They’re part of an effort to pin down when the Seaway reached various depths, the width of its channels, the location, size and shapes of islands and peninsulas in it, directions and strengths of current flows across it, etc.
A wealth of data exist from which these conditions can be reconstructed, but more and better are always welcome. That’s where the fossil log study which has so exercised your imagination comes in. Before commenting on this issue, let alone forming such an outre opinion about it, it would be wise to study the relevant sciences, such as biology, paleontology, geology, oceanography, with special reference to specialties like foram analysis. Also, please be aware that the Pliocene/Pleistocene closure of the Seaway occurred in concert with the uplift of the Andes, among other important geologic events c. 2.7 Ma.
Sorry, but it appears that the fuzzy thinking is all yours. Your stubborn adherence to a proposition so easily shown invalid has led you to make false assertions, eg that tropical plant species don’t disperse by island-hopping. For instance, I’m not surprised that you haven’t answered tty’s good question. “If the Isthmus of Panama is 10 million years old, what kept animals from using it for 7 million years?”
tty
October 25, 2014 at 7:01 am
I’m sure this has been commented upon before, but the paleontological evidence you raise is IMO dispositive:
http://en.wikipedia.org/wiki/Great_American_Interchange
Island-hopping species before about three million years ago, then major pulses in the early Pleistocene.
I note with interest that mpainter has studiously ignored your trenchant question.
TTY:
Not only did the main interchange not occur until after three million years ago, but at the time Mpainter imagines the seaway closed by the isthmus, sharks happily swam there. Recent research suggests that the area was a nursery for the famous, giant, whale-eating shark C. megalodon:
http://jpaleontol.geoscienceworld.org/content/87/5/755.abstract
Journal of Paleontology
Copyright © 2013, The Paleontological Society
Sharks and Rays (Chondrichthyes, Elasmobranchii) from the Late Miocene Gatun Formation of Panama
Catalina Pimiento1,2,3,
Gerardo González-Barba4,
Dana J. Ehret5,
Austin J. W. Hendy1,2,
Bruce J. MacFadden1 and
Carlos Jaramillo2
+ Author Affiliations
1Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA, ; ;
2Smithsonian Tropical Research Institute, Center for Tropical Paleoecology and Archaeology, Box 2072, Panama, Republic of Panama,
3Department of Biology, University of Florida, Gainesville, FL 32611, USA
4Museo de Historia Natural, Area de Ciencias del Mar, La Paz, Universidad Autonoma de Baja California Sur, AP 23080, Mexico,
5Alabama Museum of Natural History, University of Alabama, Tuscaloosa, Alabama, 35487, USA,
Abstract
The late Miocene Gatun Formation of northern Panama contains a highly diverse and well sampled fossil marine assemblage that occupied a shallow-water embayment close to a purported connection between the Pacific and Atlantic (Caribbean) oceans. However, the diverse chondrichthyan fauna has been poorly documented. Based on recent field discoveries and further analysis of existing collections, the chondrichthyan fauna from this unit comprises at least 26 taxa, of which four species are extinct today. The remaining portion of the total chondrichthyan biodiversity has affinities with modern taxa and is therefore comprised of long-lived species. Based on known records of the modern geographic distribution range of the Gatun chondrichthyans, the fauna has mixed biogeographic affinities suggesting that around 10 million yr ago, a connection likely occurred between the Pacific Ocean and the Caribbean Sea. Given the known habitat preferences for modern chondrichthyans, the Gatun fauna was primarily adapted to shallow waters within the neritic zone. Finally, comparisons of Gatun dental measurements with other faunas suggest that many of the taxa have an abundance of small individuals, in agreement with previous studies that proposed this area as a paleonursery habitat for the species Carcharocles megalodon.
Oh, no! Land sharks!
Well, since mpainter believes in the fantasies that warm currents only flow toward the poles & that plants found on continents & perpetual islands don’t island-hop, then why not also adopt a Saturday Night Live comedy skit as reality?
Lake Nicaragua does contain bull sharks, capable of living in both salt & fresh water, which swim up & downstream from & to the Caribbean, the Miocene Panamanian species were saltwater types. No whales to eat in Lake Nicaragua.
“But in a new study published in Science, a group of Rutgers researchers have found that circulation of the ocean plays an equally important role …”
Right on cue. AGW (man-made CO2 induced Global Warming) debunked, and “””researchers””” come up with another reason to call for whole new round of funding.
Darren, I wouldn´t trash this work in this way. The idea that the oceans, their circulation, and the way they are connected are a main driver isn´t that crazy. The main driver, as far as I can see, is the continental land mass shapes and geography. This in turn shapes ocean currents as well as provides a mechanism for CO2 sequestration (a shorter term mechanism is provided by cold water absorption of CO2, and a longer term mechanism by the deposition of carbonate rocks, which is really aided by fast erosion rates).
I would add that Science seems to be a much more balanced journal than anything related to the Nature publishing house, including Scientific American. Nature´s editorial policy is so distorted they have been publishing trash for quite a few years.
Same old news. Nature published it a long time ago, as well as others long before that. Hell, I recall that knowledge being accepted way back before Charlemagne…”Know this for certain, that unless you make up for your former sloth by vigorous study, you will never get any favor from Charles….” …that’s how old I am.
So, I guess one could say Rutgers is at least trying to catch up on some vigorous study. 🙂
The ocean conveyor
http://www.srh.noaa.gov/jetstream/ocean/images/conveyor.jpg
NOAA – wrong
http://science.nasa.gov/media/medialibrary/2004/03/01/05mar_arctic_resources/currents1.jpg
NASA – correct
Vuk:
Do yourself a big favor and look up Gulf Stream and Straits of Florida.
Where on earth did you get that NASA graphic?
vuk, except for that little surfacefeature called the Gulf Stream, which most definitely does not go up the East side of the Atlantic.
I have always thought these were just illustrative schematics, since there is precious little sampling at depth to let us know more. Details ( like relative volumes in each stream) are obviously wanting, evidenced by the various widths of the flows in your ‘correct’ NASA diagram–which cannot be volumetrically correct. Just more settled science that isn’t.
Thanks, I am well aware of it (see my comment further down). It is matter which one is less wrong. To us in the N. Europe, the warm Gulf current is of the most vital importance, wherever it comes from, else England would not be green and pleasant land but more like Labrador.
I find this 3D type diagram of the THC to be helpful.
It illustrates that Antarctica is “Grand Central Station” of the THC.
Apologies for the image quality.
(Does anyone know of a better version?)
https://drive.google.com/file/d/0B_RXGJAF_XL5N0lOVHdxSVNGZTQ/view?pli=1
Hi all
I agree with your observations.
Simplifying Atlantic currents flow into a simple illustration isn’t easy task. For some time I looked into various aspects of N. and S Atlantic currents and temperatures.
It is a a bit of mystery why that the North compared to the South Atlantic appears to be far more orderly in the temperature distribution ( readings from sections outlined in magenta)
http://www.vukcevic.talktalk.net/AOT1.gif
(click on graph to enlarge)
the south is less orderly due to the rapid spin of the southern ocean making a disruptive jet through the Drake Passage that spins the South Atlantic some.
Hi. EMS
Perhaps the Antarctic’s circumpolar wave (8 year period, two spokes of warm/cold sections)
http://www.spacedaily.com/images/antarctic-circumpolar-wave-bg.jpg
interfering with an overall SST pattern which otherwise would be more AMO-like.
vukcevic on October 25, 2014 at 4:39 am
Interesting. Is that where the 8 year jumps in global SSTs come from?
Antarctic’s circumpolar wave was discovered only recently, eventually more will be known
http://www-das.uwyo.edu/~geerts/cwx/notes/chap11/ant_wave.html
They are both wrong. The NASA cartoon doesn´t include the Gulf Stream. It has an imaginary current I will label “NASA´s West Africa Equatorial Current”.
Agree, I should have labeled the NASA’s as ‘possibly less wrong’.
The IPCC’s is better than those from NOAA or NASA,
http://www.grida.no/climate/ipcc_tar/slides/small/04.18.jpg
but even that is bad in the far north Atlantic (didn’t look further), I made a correction
http://www.vukcevic.talktalk.net/OCB.gif
emailed to their office, but it was ignored.
Warming oceans expel CO2, not absorb it. Millions of years ago oceans were warmer, atmospheric CO2 was much higher, and oceans were alkaline (as they are today), not acidic. Corals and other calcifying organisms evolved during periods of very high atmospheric CO2 (levels 5 to over 10 times higher than today), and recent studies have indicated no significant problems caused by decreased ocean alkalinity. In fact, fluctuations in ocean alkalinity have fallen within the bounds of natural variation.
I’ve tried to argue these points before (all except for the part about corals and calcifying organisms) but the catastrophic illusionists point back with something like ‘but nature makes so much CO2 and absorbs so much CO2 and the amount spewed into the atmosphere by man disturbs the delicate balance’ or some such garbage. Which is odd…if mankind is only responsible for 3% of atmospheric carbon dioxide and we are at almost 400 ppm, then mankind is responsible for 12 ppm…a whole 12 ppm throwing off a ‘delicate balance’. If I’m at error (which I think I might be) somebody feel free to correct.
Some on this blog argue that humans are responsible for up to 100 ppm. But even if that were true, the warming effect of CO2 is dwarfed by the major GHG, water vapor, which in the tropics runs around 40,000 ppm v 400 for CO2. It’s slightly less in the temperate zone & lowest in the dry polar deserts in winter, when there’s no sun anyway.
I see, thanks. Still puts CO2 in perspective as a relative non-driver of climate
The thought is that the human contribution has changed the balance between nature’s CO2 absorption and emission, so that 1/2 of the human component remains in the atmosphere accumulating annually.
Inform your friends that thanks to this increase in CO2, every crop on this planet now grows about 15% more food then it would otherwise, with the added benefit of not requiring any additional land or water to achieve this amazing accomplishment. Then let them know that SL rise is not accelerating, but likely slowing down, and their has been no increase in floods droughts, hurricanes, extreme storms etc.
The oceans in high latitutudes are cold. If the atmospheric CO2 content rises, the cold water does absorb CO2. The trick is to make the cold water sink. This happens if it has a slightly higher salinity than the water below.
If you check the Argo buoy data taken between Norway and Iceland you can see the slightly warmer higher salinity water current. Slightly warmer means around 5 degrees Centigrade (the Arctic ocean water is usually around 0 degrees C). The higher salinity in that current arises from its trip through the tropics (the water evaporates a bit more and the salt stays behind). A similar but not identical process takes place in the Antarctic. Surface ice formation and melting also has an impact.
Thus what we are dealing with is a very localized effect. The increase in CO2 partial pressure IS lowering pH in the ocean. The oceans happen to be a huge CO2 sink. We can use this phenomenom to estimate the ultimate CO2 concentration we could achieve (if we use up all the fossil fuel reserves listed by BP in their world factbook of energy). The answer is around 620 to 630 ppm.
Given the way things work, we can consider this CO2 absorption issue to be one of our greatest aids to help keep CO2 concentrations at a manageable level (just in case the greenhouse gas effect does increase temperatures at 1 to 2 degrees C per doubling).
I don´t think it will be nearly as bad as they are projecting. I would worry more about Ebola volunteers returning from Africa to NY and jogging in the streets as the President sits on his behind trying to pander to his followers.
My graduate school/department alma mater. 🙂
The drop in sea level definitely effected the major surface currents. They seem to need about 250 metres of depth in order to be really strong.
The Gulf Stream, for instance, which really starts at the equator in the Atlantic, mainly follows the continental shelf where there is at least 250 metres of depth. Before 2.7 million years ago, there was many more options for the directions it could have taken. It might have even over-topped the Panama Isthmus region where it would have joined the general East-West equatorial current in the Pacific (but that was probably ended about 5.0 million years ago).
There are monk seals in Hawaii & the Mediterranean, & used to be until recently in the Caribbean, because of tropical oceanic circulation. The Hawaiian monk seals were cut off from their Caribbean & Mediterranean kin by the Isthmus, just as previous tropical circulation was stopped there.
You’re right.
There does appear to have been a proto-Gulf Stream in the Pliocene. But before formation of the Panama Isthmus, warm currents ran north along northeastern South America across the Caribbean, thence into the Pacific. An emergent Central America blocked this flow and deflected it through the Gulf of Mexico to reinforce the Gulf Stream. This brought more warm water to the Atlantic Coast of North America, then across to Europe, making more moisture available to fall as snow in the higher latitudes, leading eventually to ice sheets.
So the warm water flowed into the Pacific? Why? And thence where and why again. Keep in mind that you must explain this plausibly as thermo-hyaline circulation. These ocean currents get moved about like chess pieces by some scientists, utterly without constraint.
In fact, tropical waters move poleward because that is the thermodynamics of ocean currents.
Somehow you got the mistaken idea that the Isthmus of Panama existed 10 or 40 million years ago, as per the one ludicrous paper you cited, so at some point you must have read about ocean circulation in the Miocene & Pliocene.
But if not, then the links I provided would have given the evidence for reconstructed oceanic circulation during those Epochs. Here’s another one from 2009:
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=0CFQQFjAH&url=http%3A%2F%2Fwww.clim-past.net%2F5%2F269%2F2009%2Fcp-5-269-2009.pdf&ei=mCZLVPHgHpOtyAT844HgBA&usg=AFQjCNGPEPVQJKWH7Qap_Mob9m83QQ4XDg&sig2=IcQb53MCxDmf4RH8vPQzjA&bvm=bv.77880786,d.aWw
Mid-Pliocene shifts in ocean overturning circulation and the onset of Quaternary-style climates
M. Sarnthein1,2,*, G. Bartoli1,3, M. Prange4, A. Schmittner5, B. Schneider1, M.Weinelt1, N. Andersen6, and D. Garbe-Sch¨onberg1
1Institute for Geosciences, University of Kiel, 24098 Kiel, Germany
2Institute for Geology and Paleontology, University of Innsbruck, 6020, Innsbruck, Austria
3Geologisches Institut, ETH Zuerich, 8092 Zurich, Switzerland
4MARUM Center for Marine Environmental Sciences and Faculty of Geosciences,
University of Bremen, 28334 Bremen, Germany
5College of Ocean and Atmospheric Sciences, Oregon State University, Corvallis OR 97331-5503, USA
6Leibniz Laboratory, University of Kiel, 24098 Kiel, Germany
“Abstract. A major tipping point of Earth’s history
occurred during the mid-Pliocene: the onset of major
Northern-Hemisphere Glaciation (NHG) and of pronounced,
Quaternary-style cycles of glacial-to-interglacial climates,
that contrast with more uniform climates over most of the
preceding Cenozoic and continue until today (Zachos et al.,
2001). The severe deterioration of climate occurred in three
steps between 3.2 Ma (warm MIS K3) and 2.7 Ma (glacial
MIS G6/4) (Lisiecki and Raymo, 2005). Various models
(sensu Driscoll and Haug, 1998) and paleoceanographic
records (intercalibrated using orbital age control) suggest
clear linkages between the onset of NHG and the three steps
in the final closure of the Central American Seaways (CAS),
deduced from rising salinity differences between Caribbean
and the East Pacific. Each closing event led to an enhanced
North Atlantic meridional overturning circulation and this
strengthened the poleward transport of salt and heat (warmings
of +2–3C) (Bartoli et al., 2005). Also, the closing resulted
in a slight rise in the poleward atmospheric moisture
transport to northwestern Eurasia (Lunt et al., 2007), which
probably led to an enhanced precipitation and fluvial runoff,
lower sea surface salinity (SSS), and an increased seaice
cover in the Arctic Ocean, hence promoting albedo and
the build-up of continental ice sheets. Most important, new
evidence shows that the closing of the CAS led to greater
steric height of the North Pacific and thus doubled the low-saline Arctic Throughflow from the Bering Strait to the East
Greenland Current (EGC). Accordingly, Labrador Sea IODP
Site 1307 displays an abrupt but irreversible EGC cooling of
6C and freshening by 2 psu from 3.25/3.16–3.00Ma, right
after the first but still reversible attempt of closing the CAS.”
Why do I have to do basic research for you?
Well,
Here is my type of science:
1- warm currents flow poleward because of thermohyaline circulation. The motive force is the sinking of frigid water at the pole and this process is particularly pronounced at the N pole because of the Arctic basin. Thus warm Atlantic waters have circulated poleward to the Arctic for much, much longer than the few million years posited by your isthmus hypothesis.
2- the hypothesis that NH continental glaciation is due to the isthmus fails due to the fact that presently there is no continental glaciation. Put another way,your hypothesis does not explain interglacials. Big failure.
3- You put that the continental glaciation resulted from higher precipitation rates due to the circulation changes of the ocean currents because of the isthmus.
This fails because ice cores show that precipitation doubled at the start of the interglacial. This one fact is enough to refute you.
4- The most recent studies of the problem show through several lines of evidence that the isthmus is older than ten million years and possibly dates over twenty million. The evidence results from recent work (a widening of the canal) and so the studies incorporate the latest observations, which you fail to assimilate to your thinking, instead attacking not only the man but his institution.
– so, another pet theory falls by the wayside as science progresses.
mpainter:
1. You might at least bother to learn basic terminology “thermohyaline” means something that becomes transparent when heated.
2. “the hypothesis that NH continental glaciation is due to the isthmus fails due to the fact that presently there is no continental glaciation.”
Ever noticed that big island to the upper right of North America?
4. If the Isthmus is 10 million years old, what kept animals from using it for 7 million years?
tty:
Let’s put things in the right light.
I have nothing to prove.The isthmus hypothesis is the issue.
The ill-supported isthmian hypothesis fails because of these incontrovertible facts:
1. It fails to account for interglacials.
2. Thermohaline circulation is the inevitable thermodynamics of the globe. The isthmus hypothesus blithely ignores this and sends warm Atlantic waters into the Tropical Pacific.
3. The proposed mechanism of continental glaciation, i.e., that NH precipitation was increased by the isthmian closure and that this fell as snow, etc., is refuted by ice cores which show that precipitation increases during interglacial (in fact, doubling) and decreases during glacial periods. Big problem that gets ignored.
4. Your isthmian hypothesis is restricted to North Atlantic circulation effects but such effects were limited to one portion of the NH. The ice age was worldwide. The cooling was worldwide. The warming during interglacial is worldwide. The precipitation effects were worldwide, insofar as can be determined. Trying to stretch N Atlantic circulation effects to the whole globe fails.
Discussion: well there is Panama but where are the glaciers? You point to the polar ice sheet on Greenland as if that refutes the present interglacial. It does not. The isthmian hypothesis fails prima facie.
To explain the present ice age you must explain all observations. The isthmus theory does not account for interglacial, nor such events as the younger Dryas, nor the doubling of precipitation, nor the Worldwide aspects of the present age.
Thanks Bill for settling the flame war about the isthmus closure.
The establishment of the Atlantic ocean with the closure led to the Atlantic Meridional Overturning Circulation (AMOC). This contains a positive feedback – the “gulf stream” carries saltier water toward the Arctic, which when cooled in the Norwegian sea forms the super-dense North Atlaitic Deep Water (NADW) which drives the AMOC further, the most important downwelling site apart from Antarctica.
As we all know positive feedback in a system leads to nonlinear instability and a tendancy to switch chaotically from one state to another. Thus the oceanography of the Pleistocene has been characterized and driven by interaction between on the one hand, a stably sinusoidally oscillating SH with an unstable flip-switching (AMOC-driven) NH. The best example of this is the Bolling-Allerod – Younger Dryas episode at the onset of the Holocene. Refer to figure 2 in this paper:
http://onlinelibrary.wiley.com/doi/10.1029/97GL02658/pdf
and figure 5 in this one:
http://rockbox.rutgers.edu/~jdwright/GlobalChange/Weaveretal_Science_2007.pdf
What happened to the c02 knob?
It fell off & the machine kept working as before.
Love it!
Isn’t this exactly the message that William Gray is trying convey?
https://www.google.de/url?sa=t&source=web&rct=j&ei=Z_1KVIHiLsjEPJuxgagK&url=http://tropical.atmos.colostate.edu/Includes/Documents/Publications/gray2012.pdf&ved=0CCEQFjAA&usg=AFQjCNGriQVxpgSUuQKQzgdVYFsHoJM75g&sig2=t9DtM7Xst2JH8hGWF5iYbQ
http://wattsupwiththat.com/2013/12/10/on-the-futility-of-long-range-numerical-climate-prediction/
I wish that Dr. Gray lives long enough to see the CACA madness finally tossed into the trashcan of history. Too many real “climate scientists”, not computer modelers, with the standing to challenge the false orthodoxy are going to their rewards without this satisfaction, & their young colleagues are left to be made to toe the party line of the mediocrities who have inherited the mantel of these giants of science, like Reid Bryson, “Father of Climatology”. They aren’t perfect, but are or were honest scientists, not charlatans like the CACA Team.
Always wondering what drives a warm or cool PDO, the map lines up nicely with that in the North Pacific. cooler water emerging could contribute to a cool phase of the PDO. With a 1000 year round trip time for the THC, past climate conditions are partially influencing current ones as I’d guess slightly warmer or cooler water emerges from the deep.
That IMO is part of it. But also, IMO, decades-long periods of higher solar UV irradiance & less cloud formation due to GCR modulation by solar magnetic flux lead to more El Ninos than La Ninas, causing a build up of warmer water farther east in the tropical Pacific. This migrates north along the North American Pacific coast, contributing to the warm phase of the PDO. Periods of lower UV & magnetic flux lead to a cooling.
However, like most or all climatic phenomena, more than just this is going on.
This link has the AMO PDO R^2=0.85 graph:
http://wattsupwiththat.com/2010/09/30/amopdo-temperature-variation-one-graph-says-it-all/
The recent paper by Chen and Tung: http://judithcurry.com/2014/08/21/cause-of-hiatus-found-deep-in-the-atlantic-ocean/
seems to say some heat has submerged in the North Atlantic. With down and upwellings via the THC, it seems possible that what we’re seeing in the surface temperatures is the effects of that.
milodon:
I think the ENSO region and the North Pacific have to be related. Maybe the PDO indicates the predominance of either El Ninos or La Ninas.
The ENSO-PDO relationship is my impression as of now, as well. During ~30 year periods in which El Ninos predominate over La Ninas, warm water accumulates in the eastern Pacific, as per above. And the reverse. When the switch occurs, it can be dramatic, as was the case in 1977.
Bob Tisdale considers the PDO to be an “after-effect” of ENSO. Since ENSO is likely an (intermittent) nonlinear oscillator then like a BZ reactor it could follow a Lorenz “butterfly” attractor of which the warm and cold PDO phases (el Nino and La Nina dominated respectively) are the two butterfly wings.
http://fractalfoundation.org/OFCA/lorenz.jpg
http://www.gweep.net/~rocko/sufficiency/img9.gif
IMO the PDO is not so much as aftereffect of ENSO but part of a system of heat exchange around the Pacific in response to changes in forcings, primarily solar effects.
What causes more and less El Ninos? I’d wondered about Drake’s Passage as a switch that sent cold water to the equator, with no good idea what would turn it on and off. THC cooler water emergence in the North Pacific heading to the equator seems more likely.
Ragnar,
On the decadal to centennial scale, changes in solar activity cause differences in the average frequencies of El Ninos & La Ninas, IMO.
I don’t know what the opening of Drake’s Passage did to circulation in the SH. Presumably before it was fully open with deep channels, The present Antarctic Circumpolar Current (the most important current in the Southern Ocean, & the only current completely circling the globe) flows eastward around Antarctica. So, the ancestor of the ACC may have run into South America & the Antarctic Peninsula & turned north to form a paleo-Humboldt Current. Pure speculation on my part, but seems likely.
Hallelujah! Open acknowledgement that the carbon cycle is not as simple as the IPCC would have us believe!
Kevin T. should be looking for the missing CO2 in the same place as the missing heat.
It makes sense in that anything that conveys heat into the oceans by mass transport is likely also transporting CO2.
Transporting colder water would be transporting more CO2, but, yeah, it’s an insight, like so many great insights, forehead-slappingly simple in retrospect.
Huxley is supposed to have said when Darwin explained natural selection to him, “Why didn’t I think of that?”
I don´t think it´s an original insight. It seems to be re-stating what I learned in a chemical oceanography course in the 1970´s. To be honest, I can´t find anything controversial about this paper. Nor is it that original.
“The conveyor belt is also a vital component of the global ocean nutrient and carbon dioxide cycles. Warm surface waters are depleted of nutrients and carbon dioxide, but they are enriched again as they travel through the conveyor belt as deep or bottom layers. The base of the world’s food chain depends on the cool, nutrient-rich waters that support the growth of algae and seaweed.”
http://oceanservice.noaa.gov/education/kits/currents/06conveyor2.html
If it’s vital to the food chain, it’s moving some water. I don’t know if Noaa’s generalization is correct about, depleted of CO2′? Since decayed plants sink as far as I know, the higher CO2 levels might be in the deep cool waters.
So once again skeptics are correct: CO2 is not the singular control knob of climate.
To paraphrase Dr. Ball, “If climate were a car, the sun would be the engine, water vapor the transmission, carbon dioxide one hubcap & man-made CO2 a lugnut on that cap”.
A lugnut? More like a spec of dirt caught in the tread.
Dr. Ball is being generous toward those who have attacked him so baselessly.
CO2 is a feedback mechanism. What I find interesting is to see how quality scientists have become so obsessed with the CO2 issue they start writing distorted papers. And what´s even more interesting is to see how they get through peer review and get cited and everything.
Maybe I should explain where I get my insight about these papers´low quality: I spent a lot of my career working with very high caliber geologists, who would look at paleogeography and paleoclimatology in great detail. This means I had access to great minds, and I spent years staring at their work, having discussions, and learning from them. A lot of what they did wasn´t published, but they did compile 95 % of the published material (we also had our own translators who delivered english version of Russian and othe languages as needed).
This allows me to read a paper about paleoclimatology which happens to include maps and ideas about ocean circulation patterns I happen to know are ABSOLUTELY wrong. And the thing is a lot what´s wrong is caused by simple sloppiness and carelessness. If they dug deeper the data is out there. The reason they are sloppy is because they are so obsessed with the CO2 issue they forget to cross the t´s and dot the i´s in other areas. They grab whatever fits their preconceived ideas, write a few lines, make their mistakes, and then march on.
Some scientists no matter who, forgotten to do their homework. Had they done they would have found that the impact from the Oceans on past climate changes have been known more than 100 years….
Oceans also have a fairly straightforward relationship with the current climate as well…
?w=1040&h=790
one simple graph explains a great deal
Had a good teacher in physic, chemistry and mathematic who worked together with teacher in Geography explaining parts of that back in 63-65….
Tim Ball
October 24, 2014 at 2:52 pm
Duh!!!!!! This is unbelievably shallow (pun intended). As they say, tell me something I don’t know. It is apparent they have done very limited literature research. Who is funding this nonsense?
A quick guess would be “The taxpayer”
I have this mental image of the pacific ocean hemisphere absorbing heat and the north-american/eurasian hemisphere reflecting heat, and ocean currents transferring heat in between. The closure of the isthmus of panama 3 million years ago means the direct route between the Pacific and the North Atlantic was closed and a longer less stable route round the coast of Africa meant that cosmic orbital oscillations, which had been present before without significant effects, could then induce the periodic ice ages because of the lessened stability.
However this simple scenario (which I accept is probably hopelessly simplistic if not absolutely incorrect) is not accepted even as much of an hypothesis until now because paleo-climatology essentially blamed the onset of the periodic ice ages on changing composition of the atmosphere, but are now looking towards ocean currents?
I really don’t mind a few of my tax dollars going towards studying this because it is fascinating. However I would prefer if the research was not carried out by activists attempting to prove some political point.
So they have discovered what Bill Gray has said for years.. and got paid for it.. They should send their checks to Dr Gray
“Past Climate Change Was Caused by the Ocean, Not Just the Atmosphere, New Rutgers Study Finds”
—————————————-
The above does not make much sense.
Climate change is a kind of atmospheric change….so in some respect both are one and the same in regard to the above context, as variations.
A correct expression of the meaning of above would be in the line of some thing like:
“Past Climate Change and atmospheric long term change Was Caused by the Oceans, Not just the Greenhouse Effect or the RF variation.”
But then again I don’t know of any claim in the scientific consideration of the Past Climate Change as Caused by Greenhouse effect or RF variation. Past Climate change and Past Atmospheric change are not considered as due to RF change to a degree that even the RF change does not constitute as a significant atmospheric change of any considered power to cause such a variation in climate or atmosphere as per climate change.
hope this makes some sense..:-)
cheers
You lost me.
5th paragraph really says it all about the researchers and really, the article inasmuch as they still believe that CO2 is the culprit of global warming (stop saying climate change you deceiving researchers, climate is always changing–it is you who changed your vernacular to better suit the cooling climate and busting models) when the rise in CO2 has little to nothing to do with our climate as any simple graph will show so that even a 3rd grader can see.
“Scientists believe that the different pattern of deep ocean circulation was responsible for the elevated temperatures 3 million years ago when the carbon dioxide level in the atmosphere was arguably what it is now and the temperature was 4 degree Fahrenheit higher.”
In other words, this is a ‘get out clause’ for those highly inconvenient eras in the geological record when atmospheric CO2 concentrations appeared not to govern global temperatures. The ocean circulation was ‘different’ back then. When it changed to the present day pattern via the build up of ice in the Antarctic, the NH froze and global temps declined even more. Hence we get the obligatory caveat/doffed hat to AGW seemingly necessary in virtually all climate science papers published nowadays:
“However, scientists can’t predict precisely what effect the carbon dioxide currently being pulled into the ocean from the atmosphere will have on climate. Still, they argue that since more carbon dioxide has been released in the past 200 years than any recent period in geological history, interactions between carbon dioxide, temperature changes and precipitation, and ocean circulation will result in profound changes.”
Hi Jaime.
Comparing the climate of 3 million years ago with the current climate is quasy meaningless even while we take in consideration the whole Holocene and the climate equilibrium through the warming and the cooling trend of Holocene, because the data representing the estimated climate of 3 million years ago will be representing only a climatic equilibrium of a period then, much much longer than Holocene with a much much reduced aquracy. Is like comparing apples to oranges…..
And is not only meaningless, but as far as I can tell is even beyond silly to compare the climate of the last 400 years with the estimated climate of 3 million years ago, as for the last 400 years the climate is not one in equilibrium….and long term data can not be really compared with short term data.
In long term data, whatever happends from now on, the LIA and the 20th century warming will be seen as 2 little blips at most…… and in a millenia from now both will be of no any significance as per comparing with other climatic data.
The biggest mistake of M. Mann with the hockeystick is that he attached it to long term data which were representing a clear steady cooling trend while for almost whole that time the climate was estimated as in equilibrium.
That was comparing centuries of a climate not in equilibrium with millenias of climate seen and considered in equilibrium. Far worse while considering his main intention and motive of showing the drastic (anomaly) warming of the last century.
From millenias to millions of years the gap becomes an abyss to jump in the case of such comparisions.
cheers
whiten,
I agree it’s probably not very informative to compare ancient climates with today’s but then we are all guilty of doing that to some extent. Sceptics point out that the geological record shows little evidence of a causative relation between CO2 concentration and global temperatures. This latest study invokes the appearance of the ‘modern’ pattern of thermohaline circulation to explain glaciation in the Northern Hemisphere and is tempted into suggesting that CO2 concentration was ‘comparable’ then with what it is today, therefore the large global temperature difference prior to the establishment of the new pattern of THC must require some sort of explanation. There would be much less need to try and put ancient climates into perspective with regard to our own if there was not this obsession with CO2 as a supposed main driver of climate.
@ Jaime Jessop
October 25, 2014 at 12:26 pm
Jamie.
What I was trying a say is that comparisions inbetween such different scales of data do not really help, only make and create more confusion, I did not say that ignoring and not analysing the past is what should be done, but while at it a lot of care should be taken not to mix what must not be mixed.
Besides I have got this feeling that while data closer to present and the present itself create some problem in the understanding of climate, there is a tendency to jump as far as possible in the past to try and make things a bit more easy…….and such jumps generally seem to be of a very arbitrary manner.
The current CO2 emissions can not be compared with any previous period in the past because there is no any similar period we know of in the past with the same exceleration of CO2 emissions in atmosphere.
This does not mean there is no any at all, simply it means that we know not of any such periods….and till we do know and find such periods in the past there could not be made any rational comparision in that regard, no matter how much we may want to.
You say:
“There would be much less need to try and put ancient climates into perspective with regard to our own if there was not this obsession with CO2 as a supposed main driver of climate.”
Now when it comes to something as you put it above, my own understanding is that while taking in account the time period from beginning of LIA till now, and considering the way atmosphere and climate have behaved in accordance with CO2 emissions, the conclusion I get to is: “Either the Greenhouse effect has become a climate changer (causing AGW) or it is the main driver of the climate (atmosphere) as it seems to have been always.”
In this context the CO2 emissions are only a feedback mechanism to the greenhouse effect.
That is my take, my understanding, does not necesarely mean that definitely it must be so.
Cheers
whiten,
You say,
“The current CO2 emissions can not be compared with any previous period in the past because there is no any similar period we know of in the past with the same acceleration of CO2 emissions in [the] atmosphere.”
This is not so. I quote:
” A new stomatal proxy-based record of CO2 concentrations ([CO2]), based on Betula nana
(dwarf birch) leaves from the Hässeldala Port sedimentary sequence in south-eastern Sweden, is presented. The record is of high chronological resolution and spans most of Greenland Interstadial 1 (GI-1a to 1c, Allerød pollenzone), Greenland Stadial 1 (GS-1, Younger Dryas pollen zone) and the very beginning of the Holocene(Preboreal pollen zone). The record clearly demonstrates that i) [CO2] were significantly higher than usually reported for the Last Termination and ii) the overall pattern of CO2 evolution through the studied time period is fairly dynamic, with significant abrupt fluctuations in [CO2] when the climate moved from interstadial to stadial state and vice versa . . . . The scenario presented here is in contrast to [CO2] records reconstructed from air bubbles trapped in ice, which indicate lower concentrations and a gradual, linear increase of [CO2] through time.”
http://www.academia.edu/2949675/Stomatal_proxy_record_of_CO2_concentrations_from_the_last_termination_suggests_an_important_role_for_CO2_at_climate_change_transitions
The authors then go on to suggest (inevitably) that this suggests a larger role for CO2 forcing against ocean circulation than is currently presumed during the rapid temperature changes around the end of the last Ice Age and the beginning of the Holocene. But just as easily one could presume that then – as now – short term fluctuations in temperature and atmospheric CO2 levels are effectively contemporaneous and one cannot be ascribed with any certainty to be the cause of the other
.
@ Jaime Jessop
October 26, 2014 at 7:59 am
Jaime
Thanks for the reply.
Very good point. Thanks for the information offered.
Good to know that there is periods in the past climate (Paleo) similar to the present showing that this kind of acceleration of CO2 emissions of the modern era are not quite unprecedented in nature.
I stand corrected in the point of comparision in that regard made in my previous reply to you.
Thanks again
cheers
Hello whiten,
Thanks!
Jaime
Duh. How else could the countless D/O and Heinrich events occur other than oceanic changes? They occur too fast for any other explanation. The those events turn ice-age-like temps to near interglacial temps and later, vice versa, in mere yrs.
Yet another reason why governments should stay out of the way. They fund what they choose.
It was the Antarctic ice, they argue, that cut off heat exchange at the ocean’s surface and forced it into deep water.
So they say which is more nonsense as is more often then not the case with these articles..
What is more likely is the atmospheric circulation patterns changed into a more meridional pattern(due in large part to solar variability) in the N.H. which allowed for more extensive snow coverage and sea ice coverage /ice coverage in the N.H. Once in place it then had the ability to influence the thermohaline circulation in that this ice dynamic was then extensive enough in the NH. so that at times of melting /warming of the climate (probably due in large part to solar variability) the amounts of fresh water put into the North Atlantic would be enough to slow down the thermohaline circulation and reverse the warming trend to a cooling trend and vice versa.
With the initial state of the climate brought close to glacial- inter- glacial thresholds due to this ice dynamic it was then much easier for the thermohaline circulation to change and thus influence the climate.
The bigger question is why when the state of the climate was near glacial/inter-glacial thresholds did it drift away from that state itno a warmer climate some 10000 years ago?
My candidates are earth magnetic field strength changes, solar variability with associated primary and secondary effects(cosmic rays for example which I talk about below) and Milkankovitch Cycles.
I think galactic cosmic rays decreased at around this time(around 10000 years ago) due to a strengthening of solar/geomagnetic fields which decreased clouds and allowed for warming. That is my best estimate of why.
You are the one talking nonsense. Why do you recoil from mention of the ocean like a dog recoiling from the bathtub? And return to all that irrelevant infantile rubbish about the atmosphere? The atmosphere has nothing to do with climate, only weather. Wake up!
This is what is always being over looked .
Earth’s Impending Magnetic Flip” – Scientific American
Posted on September 30, 2014 by BobFelix
“A geomagnetic reversal may happen sooner than expected,” says this article in Scientific American.
“The European Space Agency’s satellite array dubbed “Swarm” revealed that Earth’s magnetic field is weakening 10 times faster than previously thought, decreasing in strength about 5 percent a decade rather than 5 percent a century,” the article continues. “A weakening magnetic field may indicate an impending reversal.”
So far, I agree. But then the article veers way off course.
“Earth’s magnetic north and south poles have flip-flopped many times in our planet’s history—most recently, around 780,000 years ago,” the article asserts.
I completely disagree with that statement.
Why? Because it ignores magnetic excursions.
A magnetic excursion refers to those times in the past when the earth’s magnetic field temporarily headed south. Sometimes it began fluctuating and then settled down. Sometimes it moved part way south and then moved back north again. Sometimes it moved all the way south and then back north.
To my way of thinking, just because the field quickly moved back north doesn’t mean that a reversal didn’t take place. If I fall down and then immediately jump back up, that doesn’t remove that fact that I did indeed fall down.
There have been many magnetic reversals/excursions during the last 780,000 years. To name a few are the Gothenburg, the Mono Lake, the Lake Mungo, the Laschamp, the Blake, Biwa I, Biwa II, Biwa III, Emperor, Big Lost and Delta. And many more magnetic reversals/excursions have probably occurred thee past 780,000 years that scientists have not yet identified.
“The flipping takes an average of 5,000 years,” the article continues. “It can happen as quickly as 1,000 years or as slowly as 20,000 years.”
Again, I disagree. Some studies reveal that magnetic reversals can occur far faster than that. I describe one such speedy reversal in Not by Fire but by Ice.
“In a study of lava flows at Steens Mountain, south central Oregon (which erupted during a reversal, by the way), Michel Prévot, Edward Mankinen, Robert Coe, and C. Sherman Grommé found that magnetic intensity had fallen to less than 10% of today’s in less than one year.
Perhaps in less than two months.
During a follow-up study in 1989, Coe and Prévot found that the field had reversed at the rate of three degrees per day.
Perhaps in only three weeks.
Not content with their earlier findings, Coe and his colleagues took another look. The earth’s magnetic field had reversed at “the astonishingly rapid rate,” their new study found, of six to eight degrees per day. Not only did it reverse, it fluctuated. Rapid fluctuations occurred many times during the reversal, said Coe. “Enhanced external [magnetic] field activity . . . from the Sun might somehow cause the jumps.” (Coe, Prévot, and Camps, 1995) (Not by Fire but by Ice, Chapter 16)
And finally, the article asserts that “It is hard to know how a geomagnetic reversal would impact our modern-day civilization, but it is unlikely to spell disaster. Although the field provides essential protection from the sun’s powerful radiation, fossil records reveal no mass extinctions or increased radiation damage during past reversals. ”
This is so far off base that it would be laughable if it were not so serious.
Let’s look at the record.
The Gothenburg magnetic reversal of 11,500 years ago correlates with a huge mass extinction, when the mammoth, the mastodon, the sabre toothed cat, the short-fact bear, to name just a few unfortunate mammals, went extinct.
The Mono Lake magnetic reversal of 23,000 years ago correlates with a mass extinction.
The Lake Mungo magnetic reversal of 33,500 years ago correlates with a mass extinction. (Some studies even suggest that that is when the Neanderthal went extinct.)
Not only do magnetic reversals/excursions correlate with extinctions, many reversals occurred in sync with catastrophic glaciation. Here’s a chart showing those correlations.
:
I guess the magnetic reversal 11500 years ago happened to match the emergence of well armed homo sapiens? I´d say it´s more likely we exterminated them in a fashion similar to what we did in Australia, New Zealand, Madagascar, and other places.
I just wonder what is new about this? The proposed effect of plate tectonics and the positions of the continents on current flows and global temperature has been known about for a very long time. It is part of “common knowledge” and repeated everywhere. Here is just one example: http://geology.utah.gov/surveynotes/gladasked/gladice_ages.htm. According to this page:
“Today’s ice age most likely began when the land bridge between North and South America (Isthmus of Panama) formed and ended the exchange of tropical water between the Atlantic and Pacific Oceans, significantly altering ocean currents.” It also talks of rapid climate change being not unusual, in one direction or the other, sometimes over just a few decades.
The authors claim “a deeper understanding”, but you’re right. It has long been well established that the closure of the Central American Seaway led to Northern Hemisphere glaciation. Many in the CACA Team nevertheless have confused cause with effect & tried to blame falling CO2 levels.
Sturgis Hooper :
You did not make it clear whether you embraced the isthmian theory of the ice age. I can assure you that my thinking there is crystal clear: its garbage.
Several of my posts above explain why, if you are interested in knowing why I reject that theory prima facie. Oh, Sturgis, if you like insults, I can go that route, too.
mpainter October 26, 2014 at 6:04 pm
Did I not make it clear that I embrace the hypothesis embraced by every student of the issue? Well, I do. You are the only entity I have encountered which does not accept the preponderance of evidence in support of the “Isthmian Theory”. That is because all the evidence in the world supports it & no shred of evidence is against it.
None of your posts explain anything. They are all laughable dreck. Feel free to insult. Any insults by you would perforce have to be purely personal, since you have no actual scientific support for your ludicrous drivel, as the total lack of backing by readers here for your hilarious insanity should have clued you in.
Sturgis:
Insult away, but I (and others) note that you offer not one shred of support for the lame hypothesis (not theory) that the isthmian closure initiated the Pleistocene. As the advocate of a such, it is incumbent on you to present support. But your frothing insults is all you have to offer.
Now, if this makes any impression on you and you wish to show some reasonableness, go read my previous comments wherein I listed my reasons for rejecting the isthmian hypothesis prima facie. Consider them and refute them, if you dare to try. But let me say that I will not waste my time on any links, no thanks. Present the arguments yourself, like a good little scientist.
mpainter
October 27, 2014 at 7:27 am
You have provided no evidence whatsoever to support your fact-free conjecture. If you imagine that you have some, please show it. I know you can’t because you don’t.
It’s not “many” who are convinced that the Central American Seaway wasn’t fully closed until the Pleistocene. It’s everyone. Please quote a single oceanographer, geologist or biologist who thinks differently. You won’t because you can’t. The evidence is beyond overwhelming. There is even strong evidence that twice during the Pleistocene it was open again.
There is still debate however about what the CAS looked like at 12, 10, eight, six and four million years ago, whether it was a peninsula or chain of islands, how deep and wide it was, etc. This ongoing scientific investigation you have, out of your profound ignorance of the relevant disciplines, managed to misconstrue with a nonexistent debate over when it was closed.
Scientifically literate commenters here have presented paper after paper showing your religious belief false. You have not presented a single shattered shard of evidence in support of your patently ridiculous faith. Because you can’t.
No surprise that you have studiously avoided reading any of the abundant evidence supporting closure at the Pliocene/Pleistocene boundary. All you have is totally unsupported assertions, all show false by actual evidence.
The extent to which closure affected oceanic currents and its effect on climate is another debate, not as well settled as the fact of the timing of the Isthmus, but still compelling.
Stutgishooper:
The posited closure of the posited seaway by which posit is posited the redirection of a posited proto-Gulf Stream toward the Arctic where it caused continental glaciation by a posited increase in snow is waving both arms and wiggling your ears simultaneously. While you do this, you hurl gibes and insults at me for not swallowing this fantasmagoria.Well, no thanks, I know better. Wish I could help you, but I’ve had enough of the ill manners.
So, no surprise, you have nothing whatsoever to support your sick delusion, contrary to every bit of actual evidence from every actual scientific discipline.
Hence, we can conclude, as all scientifically literate readers already knew, that you are a raving crackpot lunatic monomaniac.
Thanks for clearing that up. As if it were ever in doubt.
When and if you respond, please reply to tty’s question, as I asked you to before. Why did the American interchange of species not occur ten million years ago, instead of 2.7 million, under your evidence-free imaginary conjecture?
Thanks.
Catherine Ronconi:
The evidence is stratigraphic and this is incomplete. When the stratigraphy of the Isthmus becomes better known, the issue will be resolved finally. It will show that the isthmus was emerging in the Eocene and that a shelf with an island chain was established by Miocene times.
“Your evidence-free imaginary conjecture”
You see fit to sneer. I gave the evidence but you lack the basis for evaluating it, it seems.
Yet, I will share my insights with you.
The evidence comes from the Cucaracha Formation. This was exposed in that portion of the Panama Canal known as the Culebra Cut. In recent years, in fact this year also, studies have reported fossil wood from there that dates back to the early Miocene (over 20 mya). The wood type makes it clear that this was a significant sub-aerial area and not just a shoaling island/cay.
The evidence comes from the thinnest and lowest portion of the Isthmus as naturally it was selected for the canal. Other places in the Isthmus have elevations of a thousand feet it higher (Culebra Cut disects a 100′ topographic high, the highest on the canal route, but the lowest high on the whole Isthmus for any route bisecting the Isthmus)
So we see that the lowest portion of the Isthmus was an expanse of land by Miocene times. It may be inferred that the Isthmus was mostly in place by that age, probably with extensive communication between the oceans across shelves/shoals. You need to realize that the Isthmus is built atop an ocean bed originally thousands of feet in depth and that a sub-aerial land would be the uppermost expression of a much much larger feature. The shelf aspect of the Isthmus may have persisted as subsidence alternated with accretion of sediments and other processes. Most likely it was the persistent shelf condition that acted as a barrier; however, if you are interested in this, you might want to investigate other shelves extant during the Tertiary as at the Isthmus of Tehuantepec and also through Nicaragua, which also were barriers to faunal migration (in fact, the whole of the Yucatán was a carbonate shelf from the K up to now.
But all of that is irrelevant to my main point: that the isthmian hypothesis of the initiation of the Pleistocene is insupportable and not deserving if serious consideration, the fact that many have made this lame hypothesis a favorite pet notwithstanding. For the reasons why, see my previous comments. And Catherine, if you wish to learn from people, it’s best not to sneer at them.
The stratigraphy conclusively shows what every other line of evidence shows, ie that the Seaway wasn’t closed until about 2.7 Mya.
I clearly have nothing at all to learn from you on this topic, and neither does anyone else. You are a raving crackpot, guilty of the fuzziest of “thinking”, of which you accused your obviously scientific betters.
You have done nothing but humiliate yourself publicly here, as should be apparent even to you, since you have convinced no one. No surprise, since you have not even a peg leg upon which to stand.
First order forcings are not required to realize a climate change. Only a confluence of minor processes has the potential to create weather and even catastrophic climate change (e.g. “ice age”). Well, it’s chaotic. The system is incompletely or insufficiently characterized and unwieldy.
mpainter: If the isthmian hypothesis of Pleistocene is insupportable (in your opinion), then what is cause of the start of the Pleistocene and the ice ages. Even Jaramillo acknowledges that there were east/west flowing currents in the isthmus before the isthmus finally closed about 2.7 mya. The presence of fossil trees of early Miocene age in the general region of the Panama Canal, in and of itself doesn’t prove that there was not a seaway open at that. There is ample evidence that there were north-northeast flowing currents out of the Gulf of Mexico before the isthmus closed. This last is to return to you claim that thermodynamics argues for north-south current flows You are conflating two different things. One, the presence or absence of a seaway before the isthmus closed and Two, the proximal cause of the Pleistocene ice ages. Argue one point or the other, but don’t try to argue them both at the same time.
Greymouser:
The supposed sea passage at Panama is irrelevant to the issue of the origins of the present ice age (the Pleistocene). I have given the reasons why I regard the isthmian hypothesis as not deserving serious consideration in previous comments.
Concerning an explanation of the Pleistocene (ice age), this must explain all observations: not just the glaciation, but also the interglacial. It must explain the extraordinary rise in temperature, estimated variously from 8 to 12 degrees C, this rise occurring within a few decades and accompanied by a doubling of precipitation, these facts being revealed in ice cores and confirmed through multiple lines of evidence and all of these effects worldwide.
It also must explain the return of cold conditions and glaciation, not in a sudden fashion but as a step-down over a millennia or two. It must explain the long duration of cold, dry condition punctuated by warm, wet conditions.
An alternative theory is the Milankovic cycle, and that has problems, too. I do not embrace it.
In short, there is no elaborated theory that adequately explains the ice age, IMO.
This should be no surprise, because our climate science is hard put to explain even slight climate fluctuations in our own times (in fact we can’t).
My own feeling is that the abrupt climb in temperatures that we see (not only at the beginning of interglacial but also at the beginning of those brief warming episodes known as interstadials) can only be explained in terms of insolation. Don’t ask me how.
Everyone studying the issue disagrees with you for the simple reason that all the evidence from every source shows that final closure occurred less than three million years ago. All of it.
You have previously cited (mistakenly) the Smithsonian tropical research unit. Here’s what a Harvard researcher there has to say: “No vicariant event is better dated than the isthmus”.
http://www.annualreviews.org/doi/abs/10.1146/annurev.ecolsys.38.091206.095815
The Great American Schism: Divergence of Marine Organisms After the Rise of the Central American Isthmus
Annual Review of Ecology, Evolution, and Systematics
Vol. 39: 63-91 (Volume publication date December 2008)
DOI: 10.1146/annurev.ecolsys.38.091206.095815
H.A. Lessios
Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Republic of Panama;
“After a 12-million-year (My) process, the Central American Isthmus was completed 2.8 My ago. Its emergence affected current flow, salinity, temperature, and primary productivity of the Pacific and the Atlantic and launched marine organisms of the two oceans into independent evolutionary trajectories. Those that did not go extinct have diverged. As no vicariant event is better dated than the isthmus, molecular divergence between species pairs on its two coasts is of interest. A total of 38 regions of DNA have been sequenced in 9 clades of echinoids, 38 of crustaceans, 42 of fishes, and 26 of molluscs with amphi-isthmian subclades. Of these, 34 are likely to have been separated at the final stages of Isthmus completion, 73 split earlier and 8 maintained post-closure genetic contact. Reproductive isolation has developed between several isolates, but is complete in only the sea urchin Diadema. Adaptive divergence can be seen in life history parameters. Lower primary productivity in the Caribbean has led to the evolution of higher levels of maternal provisioning in marine invertebrates.”
I find your answer a non-answer. You were the one to pooh-pooh the existence of the CAS You say …”This study is another one if those which blithely move ocean currents around to get whatever they wish. It does not work that way. dO18 records show that the ice age was a gradual decline in temp. , worldwide, starting way back in the early Pliocene.This paper has the ice age confined to the NH. Not so. More invention palmed off as science.” The planet has been in a gradual cooling phase since the start of the Cenozoic (~65mya) .and is now the coldest it’s been since the late Ordovician
So let me see if I understand you correctly. You don’t Know what causes ice ages or their various stages. Your only answer is that insolation has something to do with it. You completely ignore that global tectonics and continental position(s) affect ocean current flow/direction/temperature. You don’t consider any other source of warming or cooling. I seriously doubt you will ever find an explanation as to what causes ice ages and all the interglacials at any point in your or my lifetime.
Greymouser:
“I find your answer a non-answer”
<<<<<<<<<<>>>>>>>
You asked me for my opinions, and so I obliged. Did you imagine that I alone knew the answer? Because I promise you no one else does.
Now you seem to want to poor mouth the opinion you asked for.
If you are going to poor mouth something you should at least get your facts straight:
You claim: “The planet has been in a gradual cooling phase since the start if the Cenozoic.”
How wrong you are. Cenozoic temperatures have varied up and down with at least one ice age previous to the Pleistocene.
You show ignorance of the d18O temperature reconstructions. These show Cenozoic paleotemp. rising to the mid Eocene, declining thence to the Oligocene and then plunging to an ice age and climbing upward at the start of the Miocene, then a decline to Pleistocene lows.
You see disappointed that I did not spin out some tale of ocean currents, plate tectonics, and whirling galaxies. Well, I can only say that I base my science on observations.
I can read a d18O graph as well as the next person who is conversant with the literature. I note that from the beginning of the Paleocene to the middle of the Eocene temps climbed. but since that time the overall overall trend has been cooling; to the extent that we are now nearly as cold as it was at the time of the Ordovician ice age. You cannot ignore global tectonics and ocean currents and just blithely say that the isthmian hypothesis has no validity. Science doesn’t work that way.
I am curious though… If “The supposed sea passage at Panama is irrelevant to the issue of the origins of the present ice age (the Pleistocene)”. Why did you even bring up the subject in the first place? It appears to me that your real intent was present your opinion that isthmian hypothesis for the start of the Pleistocene ice ages was not valid.
Greymouser:
Any explanation of the ice age that does not explain the interglacials is no explanation.
The isthmian hypothesis was not raised by me, but by another. It is refuted by the latest data that shows that the isthmus was present by the begining of the Miocene. It is foolish to ignore such data, but there are many would-be scientists that do.
Redirecting ocean currents in unconstrained fashion is not my idea of scientific rigor. Plate tectonics? What about it?
You have yet to advance any support for the isthmian hypothesis. The only support I have seen is arm waving about ocean currents, which is no support, not by my standards.
And in fact, the posited closure of a posited seaway redirecting a posited current which led to a posited increase of NH snowfall is waving both arms simultaneously.
There are no “data” “refuting” the observed fact of closure of the Central American Seaway c. 2.7 million years ago.
You have not been able to produce a single shred of evidence in support of this delusion.
You show ignorance of elementary geological terminology.
The Paleocene and Eocene Epochs were warm, indeed hot at the PETM. Temperatures then started falling, Earth didn’t enter an Ice House until the Oligocene, when Antarctica became fully separated from South America and Australia. Ice sheets then formed on the polar continent, During the Miocene, the ice sheets waxed and waned, but never went away.
Just as the Oligocene glaciations were initiating by oceanic current changes following the opening of Drake Passage, so too were Northern Hemisphere ice sheets formed in the Pleistocene, thanks in large part to current rearrangement by the closure of the Central American Seaway.
Please see references:
http://en.wikipedia.org/wiki/Greenhouse_and_icehouse_Earth
Professor Don Easterbrook has explained the role of the oceans in changing climate. Here is what he has stated in the past:
“The bottom line of this is that global warming ended in 1998. We’ve had no global warming above the temperatures of 1998 since then—despite the fact that the U.N. group Intergovernmental Panel on Climate Change, predicted that there was going to be a one degree rise of temperature by 2010, it actually got cooler. Not by a lot, but a little bit.
We have been in a cooling trend now that’s related to ocean temperatures offshore that have happened. The Pacific changes modes from warm to cool to warm, there’s nothing in between. It’s like an off/on switch. It switched from cool to warm in 1977, and we had twenty years of global warming.
There is no doubt that we have had global warming—that’s not the issue. Everybody agrees there has been. The question is what’s causing it.
If there is one thing constant about climate it is that it’s not constant. It’s always changing. It has always changed. We are coming out of what has been called a ‘Little Ice Age’, which happened about 500 years ago.
For 10,000 years before that, the climate was actually warmer than it is right now, then we plunged into that Little Ice Age. We’ve been coming out of a hole ever since. The last 400 years we’ve been thawing out of the Little Ice Age, if you like. So yeah, it’s been getting warmer about one degree a century. It’s been going on. There’s nothing new about it.
So the warming we saw, which lasted only from 1978 to 1998, is something that is predictable and expectable. When the ocean changed temperatures, global cooling is almost a slam-dunk. You can expect to find about twenty-five to thirty years yet ahead of us before it starts to warm up again. It might even be more than that.” (Josh Holloway article titled Q&A: Western Professor Doubts Global Warming18 (The Western Front—13 January 2012))
Greymouser:
Some more considerations:
The Isthmus of Tehuantepec
The Isthmus of Nicaragua (at Lake Managua)
The evidence that the lowest portion (and the center) of the Panamanian Isthmus was extant (land) at the begining of the Miocene is conclusive yet it seems to carry little weight with you. You should look elsewhere for your barrier.
During glacial periods, sea level falls.
This fall was your closure of the migration barrier. To say the closure came first (and initiated the Pleistocene) has it backwards.
Again, speculation about ocean currents fails to convince. Thermohaline circulation is the ineluctable thermodynamics of the oceans and this is not started or stopped by tropical “closures”.
So far, nothing from anyone to support posited change in NH thermohaline circulation (which is governed by cooling and _sinking_of water in the Arctic .) which led to posited increase in snowfall.
mpainter: You state that the isthmus was present by the start of the Miocene.. I maintain it was not completely closed until 2.7 mya. I have seen no evidence of faunal migration through the isthmus before 3 mya. There is no doubt that the closure of the CAS had profound influences on climate, ocean circulation patterns and faunal migrations.
The Great American Biotic Interchange (GABI) started about 2.6-2.4 mya (GABI 1) also appears to be concurrent with the first of the major Northern Hemisphere Glaciations. The northward migrating fauna in GABI 1 were xenarthrans (aka anteaters, sloths and armadillos) and also rodent-like animals like porcupines. I see nothing in the literature I’ve accessed that suggests that mammalian fauna were in large abundance before 1 mya.
Whether the closure of the CAS was a proximal cause of the Pleistocene Ice Ages is still up to debate.There is no doubt in my mind that it led to the strengthening of the Gulf Stream, A stronger Gulf Stream carried saltier warmer water to Europe and lead to increased snow fall in the northern reaches of Russia and the run off from the rivers that flow into the Arctic Ocean.
As I see it, inter-glacial and glacial periods can be explained using a number of factors, 1) changes in the tilt of the Earth’s axis (from 22°2′ 33″ to 24°30′ 16″ [currently 23.4°]), 2) perturbations in Earth’s orbit (aka Milankovitch cycles), 3) changes in total solar insolation, and/or 4) changes in greenhouse gases. My guess is that all of these are largely responsible for our current ice age and inter-glacial periods.
A few mammalian species island hopped between the continents before the GABI, just as they did from North and South America to the Greater and Lesser Antilles.
Catherine:I don’t doubt that a few species island hopped before the GABI. However, mpainter is claiming that the CAS was closed because of a few fossil trees dated at approx 20 mya. We have already established that the particular specie he is talking about can migrate long distances with out being in contact with the land either by airborne seed spores or sea-borne floaters.
Yes, but mpainter has ignored that reality, after first trying to d-ny it, as in the case of every other category of evidence. He continues to imagine an alternative reality without a single shred of supporting fact.
It’s apparent that he hasn’t even bothered to read the studies he cite, which specifically conclude that the CA Seaway was 400 km wide at the time he supposes it closed.
Hard to get more delusional than this. As noted, he has misread studies trying to reconstruct the evolution of the Seaway, based upon such evidence as fossil plants, with scientific support for his totally unfounded delusion.
It’s interesting that some of the mammalian groups that did make it between the continents before the GABI were those which reached Caribbean islands in the Miocene or Pliocene as well.
How ocean currents and other changes led to the Pleistocene glaciations.
Already posted, but only in response to the discussion on the closure of the Central American Seaway. The whole article goes farther, talking about currents in the Pacific, too.
http://www.whoi.edu/oceanus/feature/how-the-isthmus-of-panama-put-ice-in-the-arctic
“The onset of Northern Hemisphere glaciation also affected the Subarctic Pacific. It led to the formation about 2.7 million years ago of a freshwater lid at the surface of the ocean, called a halocline. This Arctic halocline would have created a barrier to upwelling, which blocked deep carbon-dioxide-rich deep waters from rising to the surface. The “leak” of heat-trapping carbon dioxide into the atmosphere was stemmed, further cooling the planet.
“Many other ocean-atmosphere feedback mechanisms, resulting from the opening and closing of oceanic gateways, remain imperfectly understood. And scientists are also exploring the ramifications of other oceanic gateways.
“Mark Cane and Peter Molnar, for instance, have suggested that the uplifting and movement of the Indonesian Islands between 5 and 3 million years ago would have fundamentally re-directed less warm South Pacific water and more cooler North Pacific water through the Indonesian Seaway. The consequence might have been that the Pacific changed from more permanent El Niño-like conditions (which move heat from the tropics to high latitudes) to a more La Niña-like state (which would have curtailed the heat transfer and cooled the Northern Hemisphere).
The lessons from these vast geologic and geographic changes is both elegantly simple and excruciatingly complex. The opening and closing of seaways has a profound influence on the distribution of fresh water, nutrients, and energy in the global ocean. The coupling of these changing oceans with a changing atmosphere inevitably means a changing climate.”