No. The Miocene is not an example of the “last time it was as warm as it’s going to get later this century”… Argh!

Guest ridicule by David Middleton

From ARS Technica, one of the most incoherent things I’ve ever read…

WAIT, THERE IS HOPE! —

What happened last time it was as warm as it’s going to get later this century?

Kids today will be grandparents when most climate projections end—does the past have more hints?

HOWARD LEE – 6/18/2018

The year 2100 stands like a line of checkered flags at the climate change finish line, as if all our goals expire then. But like the warning etched on a car mirror: it’s closer than it appears. Kids born today will be grandparents when most climate projections end.

And yet, the climate won’t stop changing in 2100. Even if we succeed in limiting warming this century to 2ºC, we’ll have CO2 at around 500 parts per million. That’s a level not seen on this planet since the Middle Miocene, 16 million years ago, when our ancestors were apes. Temperatures then were about 5 to 8ºC warmer not 2º, and sea levels were some 40 meters (130 feet) or more higher, not the 1.5 feet (half a meter) anticipated at the end of this century by the 2013 IPCC report.

Why is there a yawning gap between end-century projections and what happened in Earth’s past? Are past climates telling us we’re missing something?

[…]

Can the Miocene tell our future?

The Mid-Miocene Climate Optimum (MMCO) was an ancient global warming episode when CO2 levels surged from less than 400ppm to around 500ppm.

[…]

ARS Technica

The shocking thing is that Howard Lee has a degree in geology.  The fact that he makes his living as an “Earth Science writer” and not as a geologist might just be relevant.

Can the Miocene tell our future?  I’ll let Bubba’s mom answer that question:

The fact that atmospheric CO2 levels may have surged from 400 to 500 ppm during the Middle Miocene Climatic Optimum is completely and totally fracking irrelevant in the Quaternary Period.

While the configuration of the continents was superficially similar to the modern world, there were substantial differences.

Middle Miocene paleogeography (Scotese, Paelomap)

Estimates of MMCO atmospheric CO2 levels range from less than 200 to about 500 ppm…

Neogene CO2

Neogene-Quaternary atmospheric CO2 levels.

Modern atmospheric CO2 levels are already within the MMCO range, but temperatures are MUCH, MUCH cooler than they were during the Miocene.

Neogene T

High Latitude SST (°C) From Benthic Foram δ18O (Zachos, et al., 2001) and HadSST3 ( Hadley Centre / UEA CRU via www.woodfortrees.org) plotted at same scale, tied at 1950 AD.

Oceanic and atmospheric circulation patterns were totally different in the Miocene.  Atmospheric CO2 levels are not the reason the Miocene was warmer than the Pliocene and Quaternary.

Tectonics and paleoclimate

The Miocene saw a change in global circulation patterns due to slight position changes of the continents and globally warmer climates. Conditions on each continent changed somewhat because of these positional changes, however it was an overall increase in aridity through mountain-building that favored the expansion of grasslands. Because the positions of continents in the Miocene world were similar to where they lie today, it is easiest to describe the plate movements and resulting changes in the paleoclimate by discussing individual continents.

In North America, the Sierra Nevada and Cascade Mountain ranges formed, causing a non-seasonal and drier mid-continent climate. The increasing occurrences of drought and an overall decrease in absolute rainfall promoted drier climates. Additionally, grasslands began to spread, and this led to an evolutionary radiation of open-habitat herbivores and carnivores. The first of the major periods of immigration via the Bering land connection between Siberia and Alaska occurred in the middle of the Miocene, and by the end of the Miocene the Panama isthmus had begun to form between Central and South America.

Plate tectonics also contributed to the rise of the Andes Mountains in South America, which led to the formation of a rain shadow effect in the southeastern part of the continent. The movement of the plates also facilitated trends favoring non-desert and highland environments.

In Australia, the climate saw an overall increase in aridity as the continent continued to drift northwards, though it went through many wet and dry periods. The number of rainforests began to decrease and were replaced by dry forests and woodlands. The vegetation began to shift from closed broad-leaved forests to more open, drier forests as well as grasslands and deserts.

Eurasia also experienced increasing aridification during the Miocene. Extensive steppe vegetation began to appear, and the grasses became abundant. In southern Asia, grasslands expanded, generating a greater diversity of habitats. However, southern Asia was not the only area to experience an increase in habitat variability. Southern Europe also saw an increase in grasslands, but maintained its moist forests. Although most of Eurasia experienced increasing aridity, some places did not. The climate in some Eurasian regions, such as Syria and Iran, remained wet and cool.

During the Miocene, Eurasia underwent some significant tectonic rearrangements. The Tethys Sea connection between the Mediterranean and Indian Ocean was severed in the mid-Miocene causing an increase in aridity in southern Europe (see next paragraph for more on this). The Paratethys barrier, which isolated western Europe from the exchange of flora and fauna, was periodically disrupted, allowing for the migration of animals. Additionally, faunal routes with Africa were well established and occasional land bridges were created.

Africa also encountered some tectonic movement, including rifting in East Africa and the union of the African-Arabian plate with Eurasia. Associated with this rifting, a major uplift in East Africa created a rain shadow effect between the wet Central-West Africa and dry East Africa. The union of the continents of Africa and Eurasia caused interruption and contraction of the Tethys Sea, thereby depleting the primary source of atmospheric moisture in that area. Thus rainfall was significantly reduced, as were the moderating effects of sea temperature on the neighboring land climates. However, this union enabled more vigorous exchanges of flora and fauna between Africa and Eurasia.

Antarctica became isolated from the other continents in the Miocene, leading to the formation of a circumpolar ocean circulation. Global ocean and atmospheric circulation were also affected by the formation of this circumpolar circulation pattern, as it restricted north-south circulation flows. This reduced the mixing of warm, tropical ocean water and cold, polar water causing the buildup of the Antarctic polar ice cap. This enhanced global cooling and accelerated the development of global seasonality and aridity.

UCMP Berkeley

Notice anything missing from the UCMP Berkeley discussion of the Miocene paleoclimate?  I’ll give you a hint: It starts with a “C” and ends with a “2.”

We’ve already experienced nearly 1 ºC of warming since pre-industrial time.  Another 0.5 to 1.0 ºC between now and the end of the century doesn’t even put us into Eemian climate territory, much less the Miocene.

Back to the ARS Technica nonsense…

130 feet of sea level rise

Between a third and three-quarters of Antarctic ice melted. Land liberated by retreating ice sprouted tundra and forests of beech and conifers, which can’t have happened unless Antarctic summers were warmer than 10ºC (50ºF—much warmer than the -5ºC/23ºF it is today). It’s not clear what Greenland was up to, but there may have been a small ice sheet in Northern Greenland that melted substantially.

Consequently, sea levels rose by a whopping 40 meters or so (~130 feet). To put that in perspective, Mid-Miocene-like sea levels today would draw a new US Atlantic coast roughly along Interstate 95 through Philadelphia, Baltimore, Richmond and Fayetteville, North Carolina, inundating the New York-New Jersey-Connecticut metro area, Boston, most of Florida, and the coastal Gulf of Mexico. Similar things would happen across densely populated lowland areas around the globe, home to a quarter of the world’s people.

Forty meters is just a bit more than the latest projections for modern sea level rise of 1-3 feet by 2100, and 4.5 to 5.25 feet (1.4-1.6 meters—home to about 5 percent of the world’s population) by 2300, assuming we stabilize warming to around 2ºC. The difference is, once again, partly explained by time. According to the 2017 US National Climate Assessment, 2ºC of warming would commit us to a loss of three-fifths of Greenland’s ice and one third of Antarctic ice, resulting in 25m (80ft) of sea level rise—but occurring over 10,000 years.

Even so, the Miocene hints that modern sea level rise could be larger and more rapid.

[…]

ARS Technica

2 ºC of warming would commit us to a loss of three-fifths of Greenland’s ice and one third of Antarctic ice, resulting in 25m (80ft) of sea level rise—but occurring over 10,000 years.

You can’t get there from here!

The East Antarctic ice sheet, 86% of Antarctica’s ice, hasn’t substantially melted in 8 million years.

Pages from pp1386a-2-web-23

Table 3 from USGS Professional Paper 1386-A-2.. 65 out of 80 potential meters of ice-related potential sea-level rise resides in the East Antarctic Ice Sheet. The Statue of Liberty has been saved!

Zachosetal2001_Cenozoic d18O_4

The East Antarctic Ice Sheet is stable below and probably a little above the dashed red line. Zachos temperature calculation on the right vertical axis is only for an ice-free ocean. The left vertical axis uses a conversion suitable for the Quaternary… The absolute temperatures are probably a little lower than they should be; however, the relative changes should be reasonably accurate.

The Greenland Ice Sheet didn’t even shrink by 3/5’s during the Eemian, when the Arctic was more than 5 ºC warmer than it is today.

The Greenland Ice Sheet only shrank by 1/3 relative to today during the much warmer Eemian interglacial.  X-axis is in calendar years AD(BC). A Geological Perspective of the Greenland Ice Sheet.

“Even so, the Miocene hints that modern sea level rise could be larger and more rapid.”

To paraphrase the judge in the Donny Berger case in That’s My Boy… “That  is just fracking mental.”  Warning F-bomb alert: she didn’t say “fracking.”

SL4_zps22bee1aa

Projected sea level rise through 2100 AD.

It really takes a special kind of stupid to think that a rise in atmospheric CO2 during of the Middle Miocene Climatic Optimum from 400 to 500 ppm has any relevance to modern climate change.

References

There’s a bunch of them.  I’ll get…

RoundTuit

Detailed references will be added when I get “a round tuit”… Get it? A round tuit!

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andy

Should the band of Antarctic stability extend back to about 10 or 12 million years ago ? The temperatures did not seem to change much between 8-12 million. In the High Latitude SST graph

tty

The big shift was about 14 million years age. Since then Antarctica has been completely frozen.

We have top out in the warming which has yet to exceed the Minoan ,Roman warm periods and is close to the Medieval warm period but so far away from the Holocene Climatic Optimum much less the Miocene warmth.

This is more fantasy from AGW , which by the way is on the way out.

Felix

Humans still are apes, African great apes, to be more exact.

The Miocene before and after its Climate Optimum was also warmer than now. Higher CO2 was an effect of this warmth, not an important cause.

Hoser

No, we are not apes. Apes have 48 chromosomes. We have 46.

paqyfelyc

Actually humans have 46 +/-1 chromosomes, just because two apes chromosomes merged (but they are still here)
Przewalski’s horse has 66 chromosomes, the common horse 64 , the ass 62 , the mule 63, the zebra 46, the onager usually 56 (or 55). All are interfertile and could be described as sub-species instead of species

We are not apes, but the number of chromosomes is not proof enough.

Felix

Of course we are apes. Also catarrhines, simians, haplorhines, primates, euarchontoglires, placentals, mammals, synapsids, amniotes, tetrapods, sarcopterygians, osteichthyes, euteleostomes. vertebrates and chordates, to name but a few of the clades to which we belong.

Sam C Cogar

Homo sapiens sapiens are an extant species of the Family of Great Apes.

Chromosome numbers do not determine species relationships, only reproductive relationships.

Felix

Yes, we are apes. Our large chromosome #2 resulted from the fusion of two smaller, standard great ape chromosomes.

But phylogeny and taxonomy don’t rely on chromosome number, in any case. Our ancestors were African great apes, hence, so are we.

We share with the other apes all the derived traits characteristic of apes, such as larger brain and body size, more erect posture, molar pattern, shoulder blades on our backs, no tail, flexible hip and arm joints, etc. With other African great apes, we even share some blood groups. Dunno about orangutans.

Sam C Cogar

Felix saidith:

We share with the other apes all the derived traits characteristic of apes,

Members of the family of great apes are also known as “hominids”, to wit:

hominid – any primate of the family Hominidae, which includes modern man (Homo sapiens) and the extinct precursors of man

And I have always wondered, …. which came first, …. the light skinned hominid or the dark skinned hominid?

Felix

Family Hominidae now includes the other great apes as well as humans. Superfamily Hominoidea adds the lesser apes, like gibbons, incredible acrobats. The African great apes are grouped in Subfamily Homininae.

https://en.wikipedia.org/wiki/Hominidae

Linnaeus recognized the similarities between humans and chimps, and would have put us in the same genus, but didn’t because he knew doing so would bring religious wrath down upon him.

The lesser apes have various numbers of chromosomes, but are still all apes. The genera in Family Hylobatidae and their chromosome numbers are: Hoolock (38), Hylobates (44), Symphalangus (50) and Nomascus (52).

IMO Genus Homo was originally dark-skinned, since being relatively hairless in East and South Africa selected in favor of melanin-enrichment.

Felix

Lar gibbons (Hylobates lar) at Salzburg Zoo.

comment image

The London Zoo has a large, outdoor “ape-iary” in which lesser apes can display their acrobatic skills. Or did in 1973.

It appears to be new and improved:

Sam C Cogar

Felix, what do you suppose is the “color of the skin (epidermis)” underneath the body hair of those two (2) above pictured “Lar gibbons”?

Curious minds would like to know.

Felix

Their faces are dark. Chimps have both dark and light skin.

Sam C Cogar

Felix – June 20, 2018 12:26 pm

IMO Genus Homo was originally dark-skinned, since being relatively hairless in East and South Africa selected in favor of melanin-enrichment.

Bur, Felix, that doesn’t compute, …….does it? To wit:

originally dark-skinned …… relatively hairless ….. selected for melanin-enrichment

Wouldn’t “decent with modification” more likely have progresses such as ….

originally light-skinned…… selected for relatively hairless ….. which triggered selection for melanin-enrichment

IMLO, Genus Homo was originally light-skinned, hirsute and walked quadrapedally when they took up residency on the shore of a inland “salty” sea or tidal zone ….. because of the vast quantities of easily accessible “high protein” foods that could be readily harvested from the water ……. via their quadrapeda wading in the shallow waters, …… which they eventually evolved to wade/walk bipedally in deeper water to increase their “food harvesting” ability, ……. which resulted in their evolution “selecting” for relatively hairlessness because of the “body drying factor” and the “drag” caused by their hair covered body when trying to move quickly thru the water, …… and because of their ingesting of large quantities of salt via the “salty” waters they were harvesting their food from, ….. they evolved “salt emitting” sweat glands to rid the body of that excess salt, …… thus preventing their demise.

Salt – too little or too much, will kill you dead.

Felix

Genus Homo was never aquatic. Our australopithecine ancestors lived on the savanna, as did our more recent ancestors in genus Homo.

Our skin before we lost our hair was probably like that of chimps.

The bipecal australopithecines should probably be in genus Homo, with chimps as well, but they most likely had long body hair, like chimps. Nakedness probably evolved in H. habilis and H. erectus-grade humans.

Sam C Cogar

Felix – June 21, 2018 1:54 pm

Genus Homo was never aquatic.

And “DUH”, Genus Homo was never ungulates.

Felix, your above statement was so scientifically brilliant, intellectual and knowledge based that it almost made me puke on my keyboard when I read it.

Are you so cluelessly miseducated that you don’t realize that billions of people (humans) have survived by harvesting 80% to 95% of their food via an “aquatic source”, …. rivers, lakes, seas, oceans and/or rice paddies.

It is literally impossible to intelligentally discuss science with a “mimic”.

Felix

Lake Turkana, Kenya, is salty, but potable. I don’t know how much fresher it might have been in the Pliocene or early Pleistocene. It used to drain into the Nile, but I also don’t know when the switch in watershed occurred.

The other major Rift Valley lakes are fresh.

Australopithecines and early Homo may well have eaten lacustrine food sources, but there is no evidence that they lived in the water. We know that anatomically modern humans in South Africa some 120 Ka lived by the shore and used marine resources. A stone fishing hook or harpoon from Africa has been dated to 70 Ka.

Our sweat system did not evolve because our ancestors were aquatic mammals. Like other African animals, we came to water holes, lakes and rivers to drink, and found things to eat there as well.

Sam C Cogar

So sayith Felix the “mimic” – June 21, 2018 2:44 pm

but there is no evidence that they (pre-humans) lived in the water.

Felix, are you also going to tell me that there is no evidence that humans evolved from alligators?

We know that anatomically modern humans in South Africa some 120 Ka lived by the shore and used marine resources.

Shur nuff, Felix, so why are you “stuck-on-silly” via your [Snip] act of inferring that I stated or claimed that our pre-human ancestors evolved and lived in the water as an aquatic creature? [Snip]

Our sweat system did not evolve because our ancestors were aquatic mammals.

Felix, why in hell would an aquatic (water residing) animal have a need for evolving “sweat glands”, …… to cool their body, ……… HUH?

But anyway, Felix, [Snip] ponder the following commentary, and then tell me what you disagree with and why, ……. [Snip] to wit:
………….

The evolution of bipedal locomotion, loss of protective body hair and the growth/formation of “sweat glands” over their entire epidermal skin area are just three (3) of the physical attributes that our early human ancestors (the only living sub-species in the Family of Great Apes) acquired during the past two (2) million years, ….. for them to best survive in the environment that they chose to live and reproduce in.

So, the question is, what was their selected environment like that best suited a bipedal stance or movement, ….. did not require the protection of a heavy coating of body hair, ,,,,, but absolutely, positively required that their entire body surface (epidermis) contain sweat glands that secrete copious amounts of salt (NaCl) containing water (H2O).

Surely that environment was not a hot, semi-arid African savannah, …. simply because salt (NaCl) and water (H2O) are the two (2) most important, precious resources necessary for pre-human or human survival, ….. and thus it would be highly detrimental to one’s survival if they indiscriminately rid their body of said without an immediate means of replacing said losses. Too little, or too much water (H2O) or salt (NaCl) is a cause of certain death to humans.

As far as anyone knows, ….. the evolving of “sweat glands” in the epidermis covering of the human body may have specifically evolved for ridding the body of excess salt (that was/is ingested as a result of their primary food source) …… because the retention of too much salt will kill you “deader than a door nail”, There has been more than one (1) human that has died from drinking “salty” water. And a “heat stroke” is the result of “sweating out” too much of the body’s salt content.

If one is only focusing on or only considering “human furlessness”, …. then I agree, one will not readily see anything particularly aquatic about it. And the same goes for human bipedalism, you won’t see anything particularly aquatic about it either. But you can’t be “focusing on” human furlessness or bipedalism if you are going to apply a kind of “reverse evolution” to determine the environmental “driver” of said attributes. Thus said, one has to focus on the “environmental driver(s)” responsible for the evolved attributes, …… and not the attributes themselves.

Thus, it is of my learned opinion that human “furlessness” is a direct result of human “bipedalism”. In other words, human bipedalism was the “environmental driver” responsible for human furlessness.

And I say that because, if our early human ancestors had never evolved the ability of bipedal walking over the course of 300K or a million years, ….. then there would not have been any logical reason (environmental driver) for their body to evolve furlessness. Human bipedalism and furlessness go “hand-in-hand”, no need of one without the other.

And, the next obvious question that I am sure you will want me to provide an answer to/for is: “And just what is the “environmental driver” responsible for human bipedalism?”

And the simple answer to the aforesaid question is, ….. our early human ancestors, which eventually evolved to be a sub-species of the Family of Great Apes, established a close association with an aquatic environment by taking up residence on or near the shoreline of a river, lake, tidal zone or inland sea simply because said body of water (H2O) provided them an easily accessible, abundant supply of high-protein foods that did not require the expenditure of great amounts of time and energy, …… or the use of tools, …. for harvesting said food or for eating of said foods. Life is good …… for any animal species that doesn’t have to spend all their waking hours searching for food and evading predators.

And bipedal walking evolved as a result of ….. harvesting their food from the shallow waters. It is quite easy to learn to walk bipedally by walking (wading) in water because the water provides buoyancy to easily hold oneself in an upright position. And thus, our early ancestors that were the best bipedal waders/walkers in the water ……. were also the bestest provider of aquatic foods ….. and the bestest food provider got to do the mostest procreating with the females.

Loss of body hair/fur by early humans resulted in the loss of a protective covering of the epidermis, which meant that it would have been highly improbable for early humans to walk or run amongst or through the brush, weeds, thorns, briars, etc., of the hot/dry African savannahs while looking for tubers or fruits, …… or either trying to catch a prey animal or trying to evade a predator animal ……. without their “bare” skin being cut, scraped, gouged and/or lacerated …. which would have surely resulted in their demise. Loss of body hair/fur also meant a loss of protection from blood-sucking and biting insects that commonly inhabit brushy fields, grasslands, savannahs and hot/humid locales.

Loss of the majority of body hair/fur by early humans meant that they could more easily walk or wade bipedally in the water when harvesting aquatic foods. Heavy or thick body hair/fur would cause a severe “drag” on quick movements required to capture aquatic prey animals, especially in deep water.

Humans retained their body hair under their arms and between the legs in their groin area simply because said patches of hair serves the purpose of a “dry lubricant”.

And humans retained their body hair on their head most likely because of their bipedal stance. It protected their head and brain from the solar irradiance …… as well as providing a “glare reducing” aid or shield when bipedally walking in the water harvesting their food.

“YUP”, the harvesting of their aquatic grown foods whose remains provided them with a variety of “natural tools” (bivalve shells, spines, claws, fish bones, etc.) that didn’t need any “inventing” by those early humans, …… who just had to figure out how best to use them for other purposes. And they had plenty of “free time” to do their “figuring” ….. because they were not spending all their awake hours searching for food and evading predators.

It is utterly asinine and idiotic for anyone to claim that our early pre-human ancestors expended 200/300+ thousands of years on the African savannahs, at first evolving to walk bipedally, then to run bipedally, in order to chase down, kill and butcher Savannah living animals in order to acquire a sufficient source of high-protein foods, …… that they required for evolving a large brain and greater intelligence, ……. that was prerequisite to them being capable of “inventing” the tools ….. that was absolutely, positively necessary for the killing and/or butchering of the aforesaid animal protein.

Cheers, …… S C Cogar

[Let’s avoid making personal accusations to motive or intent. -mod]

Sam C Cogar

I apologize …… for oftentimes getting frustrated at persons for not paying attention simply because they are so engrossed in their “daydreaming” of entities and/or events that could not possibly have been a reality associated with the natural evolution of plants and animals on planet earth.

Like a “daydreaming” student in a classroom, one has to “get-their-attention” before they can be taught anything of vale.

GregK

Shrews were also our ancestors but we aren’t shrews.
https://www.livescience.com/26929-mama-first-ancestor-placental-mammals.html

Felix

While that mammal looks a little like a shrew, it isn’t one. We and shrews share common ancestors, but that doesn’t make us shrews or them humans.

Placental mammals (Eutheria) probably evolved among Mesozoic insectivores, but modern shrews didn’t emerge until the Middle Eocene. Hominids and shrews are both eutherians (placental mammals), but not particularly closely related. We are closer to “tree shrews”, which aren’t shrews. They’re in the same superorder as primates, Euarchontoglires.

Felix

Two cladograms derived from different scientific interpretations of evolutionary relationships of mammals based on morphological (left) and genetic (right) characters of species. Trends in Ecology and Evolution. 19: 430-438.

comment image

Duster

Both the horse and the ass belong to genus Euidae. Note the difference in chromosome counts. Human are great apes. Humans and chimps belong to the same family, sub-family and “tribe” – a subclssification I had never run into before. Humans and Chimps are separated only at the Genus level. Chromosome counts are not all there is to the issue.

Felix

Were the same standards to apply to African great apes which obtain elsewhere in animal kingdom classification, chimps and bonobos (Pan) and humans (Homo) would be in the same genus.

wws

Don’t you dare say that! ABC will cancel your show if you do!!!!

Felix

This might also have contributed to MMCO CO2 levels:

https://en.wikipedia.org/wiki/Columbia_River_Basalt_Group

Felix

There were also two supervolcanic eruptions of the (now) Yellowstone Hotspot around or during the MMCO:

comment image

Good addition Felix. Those “spots” with age dates are the super-volcano/caldera locations, bot the hotspot moved continuously. That trend is also a gold trend, along with associated features both south and north of the trend, like the famous Sleeper gold mine in Nevada. Yes, even Yellowstone National Park where “fishermen” have been found panning gold below the lower falls.

Felix

The hot spot doesn’t move. The North American plate moves over it, traveling southwest, which makes it look as if the hot spot is going northeast.

crosspatch

The portion of the North American plate that is now moving over the hot spot is much thicker than the crust that was over that spot in previous eruptions. The crust thickens very quickly with very little distance as you go east from the current caldera. With every passing century the crust over the hot spot is thicker. This might be enough to shut it down from further eruptions though it could generate quakes and faults in the main continental crust. Something like that might be going on around New Madrid.

Felix

We can only hope you’re right.

oops! I posted a reply tp crosspatch in the wrong reply location. I’m fairly sure that felix doesn’t relish the thought of more explosive volcanism in the heartland.

Felix is right that the hotspot is fixed and the North American plate moves over it. crosspatch is right about thicker plate moving over the hotspot, however I don’t think this is good news. The converted oceanic crust further west produced more mafic melts than the current Yellowstone site, and even more felsic melts would be expected further east. More felsic generally equals more explosive, and this tendency is detectable along the melt trace.

Felix

OK. I retract my hope. Maybe erupting less often, but more explosively.

So, either way, we’re doomed. But probably not immediately.

Unless the Russians perfect the geological warfare of which they’ve dreamed.

Felix

http://www.businessinsider.com/russian-analyst-says-to-nuke-yellowstone-2015-4

Russian ‘Doctor of Military Sciences’ says Moscow should just nuke Yellowstone if tensions boil over

Or the San Andreas fault.

Roger Bournival

The year 2100 stands like a line of checkered flags at the climate change finish line, as if all our goals expire then.

If memory serves, every major prediction by Gore (Artic ice) and the other warmists from the Original Earth Day in 1970 onwards that a date certain before 2018 would bring upon us great calamity if we didn’t do this or that to ‘save the planet’ has come up snake eyes. I stopped reading that Ars Technica article right then and there.

wws

Yup. After those predictive failures, they at least realized they needed to move the date of “THE END OF EVERYTHING!!!” to just a little bit past the lifespan of anyone who could read their predictions. Best way to make sure they can never be proven wrong during the author’s lifetime.

commieBob

The Mid-Miocene Climate Optimum (MMCO) …

It’s called optimum for a reason.

op·ti·mum/ˈäptəməm/

adjective

most conducive to a favorable outcome; best.

noun

the most favorable conditions or level for growth, reproduction, or success.

Clearly it is currently not warm enough.

Felix

Same goes for the Holocene Climate Optimum, which was at least two K warmer than now globally and a lot more in the Arctic.

tty

Perhaps not two degrees globally, there is little land data from the tropics, but certainly at least two degrees in the temperate zones.

Felix

You’re the expert. But even if the tropics were the same as now, high latitudes would have been more than two degrees warmer. Tropics obviously cover more area than the poles.

This shows less than two degrees, but also assumes that present global average T is (or was in 1995) 15 degrees C:

http://www.lwhancock.com/images/HoloceneOptimumTemperature.jpg

TDBraun

I don’t like it when an author here calls the author he is criticizing “stupid” and belittles him personally, as this author does. It is bad form and wins no converts. Just say the article is nonsense and explain why and leave the superior attitude out.

Alley

“Guest ridicule by David Middleton” This is from Middleton, someone who seems to have a beef with the educated staff at Ars. Middleton not only insults like a child, he doesn’t understand adjustments. Even Curry shakes her head at such absurd non-science.

commieBob

… educated staff …

Education produces as much stupidity as it cures. Nassim Taleb describes the situation eloquently as intellectual yet idiot.

MarkW

When you decide to make it up, you go all out.
BTW, I love it when you declare that to be intelligent, we have to agree with you.

PS: If you were half as intelligent as your mom says you are, it should be trivial for you to point out all the places were David is wrong. The fact that you don’t bother says a lot.

TDBraun, I think stupid is correct re definition: stupid: to have or show conduct associated with a slow mental process. Go David, Go! Geologists should throw f-bombs at this level of stupid.

Stephen W

All they need to say is..
IF CO2 is the main control knob of the climate.. THEN returning CO2 levels to levels of a previous warmer period with similar geographic conditions will make today’s temperatures the same as that previous period.

Since todays temperatures aren’t as warm, then they would then have to reject the hypothesis that CO2 is the main control knob.

It’s pretty simple science, I don’t know why so many people struggle with it.

DW Rice

Stephen W

“Since todays temperatures aren’t as warm, then they would then have to reject the hypothesis that CO2 is the main control knob.”
__________________________

The counter argument is that today’s temperatures don’t yet show the full picture. The story goes that so called ‘equilibrium climate sensitivity (ECS)’, or the ‘new near steady state’ caused by increased CO2 levels, won’t be realised fully for decades or longer, due to the slow overturning of heat in the global oceans.

For instance, if doubling CO2 in the atmosphere causes ECS warming of, say, 3 deg. C, then if CO2 concentrations peaked at 500 ppm, average surface temperature would equalise out at around 2.5C above pre-industrial; but that wouldn’t be expected to happen for decades at least. If ECS is at the low end of the latest IPCC range, 1.5 deg. C, then 500 ppm CO2 would equalise out at around 1.3 C above pre-industrial.

Regardless of what ECS actually is, the point is that ‘today’s temperatures’ aren’t regarded as a reliable indicator of eventual ECS, so can’t be compared directly to temperatures that reached equilibrium during previous periods when CO2 levels were continuously as high as they are today.

MarkW

Stephen, the come back to that is to point out that CO2 levels have been rising for almost 70 years, but temperatures have barely moved during that period.

D. J. Hawkins

Also, based on Keeling’s data, there is a seasonal fluctuation in atmospheric CO2 that is not reflected in the temperature record. Additionally, on a year-over-year basis CO2 has shown a monotonic increase since 1950, while temperatures have gone down, up, and flat, providing counter evidence to the coupling of surface temperatures and atmospheric CO2 content.

Weylan McAnally

Perhaps we should conclude that CO2 has zero impact on Earth’s surface temperatures? Maybe the Sun’s activity, atmospheric mass and gravity control baseline surface temperatures while ocean cycles determine short/mid term climate trends. Is this incorrect?

Felix

And, for the first 32 years of the postwar rise in CO2, Earth cooled dramatically. Then, after the PDO flip of 1977, it warmed slightly until the 1998 super El Nino. Then its temperature stayed flat until the 1916 super El Nino, the effect from which the planet is now rapidly cooling.

The interwar period was actually warmer than the late 20th century warming, but the corrupt, book-cooking “data” gatekeepers have cooled it down, while warming the postwar cooling.

MarkW

If 500ppm is going to warm the planet by 8C, then the oceans should have been boiling back when CO2 levels were above 6000ppm.

joelobryan

“resulting in 25m (80ft) of sea level rise—but occurring over 10,000 years.”

I suppose the Geology Genius Howard Lee has forgotten that we are still in the Pleistocene. Our current cozy interglacial Holocene will likely be a distant forgotten memory in 10,0000 years as the Laurentian Ice Shield creeps down out of Arctic Canada and nothing but full on nuclear or fusion power will be all that can save whatever exists of humanity in that time.

tty

8 meter sea-level from WAIS is completely unrealistic. It probably does not factor in that much of the WAIS is below sea-level and thus must first “fill out the hole it makes on melting”.
3 meters is more realistic:

https://www.researchgate.net/publication/24428838_Reassessment_of_the_Potential_Sea-
Level_Rise_from_a_Collapse_of_the_West_Antarctic_Ice_Sheet

And 5 degrees of arctic warming in the Eemian is on the low side. There are few arctic sites with less warming, but many with more. In Eastern Siberia it was regularly more than 10 degrees warmer than now (but no CH4 release, please note). For the Greenland and Antarctic Icecaps these temperatures are relevant:

Greenland (from S to N):
Pakitsoq: 4 degrees
Renland: 5 degrees
GISP2: 6 degrees
GRIP: 5 degrees
NGRIP: 5 degrees
NEEM: 8 degrees

Antarctica (from N to S):
EDML: 4.5 degrees
EPICA Dome C: 5.5 degrees
Dome Fuji: 6 degrees
Taylor Dome: 8.5 degrees
Vostok: 4 degrees

Bruce Cobb

“And yet, the climate won’t stop changing in 2100”
The sheer brilliance is truly awe-inspiring.

Bill Illis

The Miocene was only 3C or 4C warmer than today. As I noted recently, all those temperature scales on paleotemperature history on the internet now are wrong. And CO2 was mostly in the 250 ppm during the whole period so it wasn’t CO2 that made it warmer.

What did make it warmer for a time is that the Antarctic Circumpolar Current got disrupted and shut-down. This allowed Antarctica to warm up and it lost probably 50% of its glaciers. Less ice albedo, warmer Earth.

The dozens of little cratons between South America and Antarctica got jostled around due to continental drift and this stopped the Circumpolar Current from flowing properly through the Drake Passage. Antarctica was no longer isolated in an extreme polar climate.

comment image

And then the period just before Antarctica froze over 34.5 million years ago to when it lost half its glaciers and then the end of the Miocene when Antarctica froze over again.

comment image

From:

https://www.sciencedirect.com/science/article/pii/S0012821X09000065

Felix

Thanks to you both. A highly plausible explanation.

CO2 need not apply.

Tom Halla

It is still probably not yet as warm as the Medieval Warm Period, let alone the Roman or Minoan, so the dread effects would be unlikely.

tty

During the MWP it was possible to grow Grapes in Norway and Barley in Greenland, and that hasn’t happened yet.

NorwegianSceptic

Not sure about Norway, but definitively in Denmark:
https://www.tandfonline.com/doi/abs/10.1080/21662282.2017.1293397

(I have tried for a few years with two vines in my garden, but the yield has not been much to brag about…..).

tty

There are a lot of archaeological finds of grape pips from Norway during the MWP. So unless the Vikings imported massive amounts of raisins…

Tom Halla

“It is still probably not yet as warm as the Medieval Warm Period, let alone the Roman or “Minoan, so the dread effects would be unlikely.”

But,
But,

Surely we are all doomed!!?

Auto – with acknowledgements to ‘Dad’s Army’.

Felix

If it ever gets as balmy as during the Minoan WP, maybe this fashion will come back into vogue:

comment image

Except with the head still attached.

tty

And remember, during this very warm interval (when there were monkeys and parrots in Germany and Sequoia forests in Arctic Canada for example), Antarctica was still mostly glaciated, with a very sparse tundra vegetation and fauna on the ice-free coastal strip, much poorer than e. g. Greenland (except perhaps the northernmost parts) today:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2495011/

https://www.researchgate.net/publication/234038998_Tundra_environments_in_the_Neogene_Sirius_Group_Antarctica_Evidence_from_the_geological_record_and_coupled_atmosphere-vegetation_models

joelobryan

I’ll further make the point I made yesterday on another thread.

Once you go back before the current Quaternary Period (which we don’t really understand what triggered the start of cooling and glacial cycles, maybe it was Panama closing off, but that is still mostly a guess), other possible explanations cannot be eliminated.

Molar gas ratios can be determined from various isotope ratio proxies. But those say nothing about absolute pressure.

So the big uncertainty before the Quaternary is what was the Seal Level Atmospheric Pressure (and by extension atmospheric mass)?

Using wet adiabatic pressure vs temperature charts, it would only take about a 10% increase in SLAP (from today’s 1013 millibar to 1114 millibar= 111.4 kPa) to get a tropics 5 ℃ temperature rise and an almost 9 ℃ surface temp rise in the drier polar climate.

Felix provided this graph which is quite relevant to questions about Earth’s climate temperature 5 Mya to 23 Mya.
comment image

If that graph is accurate, the warmer Middle Miocene (14-15 Mya) climate is completely explained by a higher SLAP of 120 kPa (20% higher than today).

But we simply do not have accurate enough proxies to understand what the atmospheric pressure (atmospheric mass) was 15 million years ago.

tty

The amount of nitrogen has probably not changed much, but the oxygen has varied quite a bit.

Felix

The active volcanism of the Columbia Basin basalt flows must have released a lot of gases to the atmosphere, but even with other eruptions during the MMCO, probably not enough to raise SLAP by that much.

Felix

I suppose that the graph is based upon temperature reconstructions, with assumptions as to the effect of T on pressure.

joelobryan

Then it simply becomes circular, much like today’s climate model tuning to the past and then claiming skill in the recreating past temps.

Felix

If my conjecture be correct, then, yeah.

But I don’t know if I’m right or not, not having read the derivation.

Safariman

Cause for alarm? Atmosphere escaping…unaddressed by all!

Weylan McAnally

If the atmosphere was escaping into space, wouldn’t we see a consistent cooling as the mass of the atmosphere declined (assuming gravity remained constant).

Alasdair

Yes: The sea level atmospheric pressure (SLAP) is vital here as it determines the temperature at which water starts to evaporate and thereafter control the global temperatures. This being done by means of the atmospheric Rankine Cycle enabled by the simple fact that gaseous water is lighter than dry air and hence rises carrying with it the large latent heat up for eventual dissipation to space.
I will repeat what I have said before: So long as the kettle in my kitchen boils at 100C I have no worries about CAGW.

Javier

It is just hopeless. Nearly everybody in climate academia equates CO2 level to temperature both in the distant past and in the future. And since models have been built with that assumption, they confirm it, so everybody rests assured that they got it right. They are not even aware that it is an assumption anymore.

The fact that CO2 has increased enormously to levels not seen in millions of years, while temperature has barely bulged should give them pause, but no. They are as sure it is coming as the first Christians about the second coming of Jesus.

It is the most pathetic dark period of science since leeches were abandoned as the main medical cure-it-all.

Felix

Leeches have more medical applications than GIGO consensus “climate science” has validity.

The GCM assumptions are a horrifically costly instance of the logical fallacy of begging the question.

bwegher

One paper in an ocean of scientific investigation of global climate.
Note that the Miocene includes a major shift in global climate just after the MMCO, called the Middle Miocene Climate Transition (MMCT), which is another “permanent” shift in climate toward a colder Earth.

For those interested in the MMCT, one place to start is the work of Shevenell.
http://www.pnas.org/content/pnas/113/13/3419.full.pdf
and
https://pdfs.semanticscholar.org/96de/bbb36eb1a18be76410e962d9c3738fd1fb7b.pdf

The more you learn the more you understand that CO2 change is a biological response to temperature change.
Earth’s atmosphere has been evolving due to planetary biology for over a billion years. The entire atmosphere of today is a product of biological influence, and hemostatic feedbacks. The only exception is Argon, due to radiological decay of primoridial Potassium-40

Felix

The O2 content of the air is surely biological in origin, thanks to the evolution of cyanobacteria some 3.5 Ga, leading to the Oxygen Catastrophe of ~2.45 Ga, after iron in the ocean had combined with free oxygen to form rust.

There is now a biological N cycle, but nitrogen gas first entered the atmosphere from volcanism. Geothermal heat released N2 from solid N compounds. Ammonia (NH3) was also probably present in the early atmosphere.

bwegher

There is some debate over the evolution of the biogeochemical nitrogen cycle.
Section 3.3 of his review paper shows the basics. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5412885/

The following link shows the current view of the basic biological portion of the nitrogen cycle. Bacteria control atmospheric N2 with both anerobic and aerobic pathways.
https://www.sciencedirect.com/science/article/pii/S0960982215015183

The simple diagram shows the fluxes and reservoirs of global Nitrogen.
The global atmospheric Nitrogen pool is entirely of biological origin with a 10 million year turnover time. Biology has completely erased Earth’s primordial atmosphere.
Only Argon is of abiotic origin.
https://www.ess.uci.edu/~reeburgh/fig3.html

Hoser

The assertion of the dominance of biological processes on CO2 is supported by the model [ew!] of CO2 fluctuation measured by the NASA OCO2 mission. It’s funny to hear NASA narrator dodge the obvious conclusions.
https://youtu.be/x1SgmFa0r04

bwegher

That video is a model of the NASA prediction of what OCO2 was expected to show.
About as accurate as a Disney animation of Snow White is to a real human.

The OCO2 mission was intended to have the capability to resolve anthropogenic CO2 sources from natural CO2 fluxes. Read the papers describing the reasoning underlying the engineering design of the OCO.

The actual output of the OCO2 mission is huge in that the satellite performed its mission well, and showed the real world was exactly as the sceptics understand the carbon cycle.
The actual data and subsequent analysis from OCO2 show that the human CO2 fluxes are NOT resolvable from natural CO2 surface sources. The real OCO2 output bears no resemblance to that NASA video.

OCO2 shows absolute proof that human CO2 does NOT contribute substantially to the global biogeochemical carbon cycle. Human addition of CO2 to the atmosphere is insignificant, about 20 ppm at the present time.

CO2 does NOT “accumulate” in the atmosphere on any time scale. The entire mission is a total embarrassment to NASA. That’s why no one ever hears anything about the mission anymore.

If the OCO2 showed what NASA expected, the real data would have been hyped by everyone involved and every climate warmist would be screeching OCO2 to the end of time.

The OCO2 story is being completely ignored because it actually disproves the entire CO2 media freak show.

I urge everyone interested in the “global warming” meme to look closely at the real results of the OCO2 mission

Clyde Spencer

It appears that this animation was produced about a month before the first official OCO-2 map was presented at the December 2014 AGU meeting. If that is the case, then this animation appears to be what NASA expected to find, not what they found.

Hivemind
Crosspatch

I recently discovered a television show called Drunk History. Maybe we should have one called Drunk Science.

ЯΞ√ΩLUT↑☼N

That’s a level not seen on this planet since the Middle Miocene, 16 million years ago, when our ancestors were apes. Temperatures then were about 5 to 8ºC warmer not 2º, and sea levels were some 40 meters… blah blah blah..

Even if true, these conditions didn’t last AND there was no runaway greenhouse, ever. The apes flourished under these conditions and I can prove it all by typing this right here and now.. 🙂

Jeff Alberts

“Why is there a yawning gap between end-century projections and what happened in Earth’s past? Are past climates telling us we’re missing something?”

Yes. They’re telling you that CO2 is an effect, not a cause. Duh.

I agree with the theme of this post, but have some issues with UCMP Berkeley.

The major uplift of the Sierra Nevada is Pleistocene, not Miocene. The granites themselves are mostly Mesozoic, and were eroded to flat planes that can be seen on the summit plane of Mt. Whitney and several other major peaks. There was a lot of Miocene volcanism in the Cascades, and even the California Coast Ranges. Pliocene volcanics buried most of the Sierra north of about Sonora Pass.

I seriously doubt the Bearing Strait was a migration route for any animals not very good swimmers or filers, certainly not apes of any stripe, until sea levels dropped in the Pleistocene.

Felix

I’ve wondered about Miocene sea level, since, while the epoch was warmer than the Pliocene and especially the Pleistocene, animals did clearly move from Asia to North America.

Mastodons, for example, appear to have arrived in NA around the Miocene-Pliocene transition, but possibly earlier. Maybe they swam across the Bering Strait.

MarkW

Modern elephants are good swimmers.

Felix

Yup.

Technically, mastodons aren’t elephants, ie members os Elephantidae, the elephant family, but close enough for aquatic purposes.

comment image?code=cell-site

The Mammutidae are the mastodons.

Pleistocene North America had a plethora of proboscideans. Besides the woolly and Columbian mammoths (to include island dwarfs, plus the possibly separate species Imperial), our continent was blessed with the mastodon and even gomphotheres in its southern reaches.

michel

You may be tempted to post a rebuttal of Lee’s nonsense at Ars. Do not bother. The clique of hysterical warming fanatics will first downvote your post until its automatically hidden from view, and then their science editor, John Timmer, will first attack you personally in the forum, then ban you from further posting.

Timmer, presumably with the support of Conde Nast, operates a policy that climate stories and comments shall contain nothing that might cast any doubt on the most alarmist view of climate issues. Nor may there be any skepticism about wind and solar, which are going to reduce emissions and save the planet.

You can see from this story another typical phenomenon – one that affects the whole of the climatist persuasion, but is particularly marked at Ars.

After the most dire predictions of disaster, a few requirements for a remedy are trotted out. In the case of the present article they include not simply going to zero emissions, but starting to reduce actual concentrations of CO2 in the atmosphere by 2030.

Every five years of delay on doing this is said to result in an additional one meter rise in sea level in future:

Although Greenland and West Antarctic ice is already melting at an accelerating rate, East Antarctica is—for now—relatively stable (except the Totten Glacier). So, if we can keep warming well below 2ºC, DeConto and Pollard’s models suggest East Antarctica will contribute little to future sea level rise.

But this will require us to reduce greenhouse gas concentrations, going beyond achieving “Net Zero” emissions….But this assumes negative emissions technologies can be deployed massively by the 2030s, a scenario with “limited realistic potential.” Every five-year delay could commit our descendants to an extra 1 meter (3 feet) of sea level rise by 2300..

Now, you might think that someone so desperately alarmed with such catastrophic threats to civilization from global emissions would start to wonder who is doing it and what they have to do to stop it?

Wrong. Notice the characteristic ‘we’ as invoked in this piece. ‘We’ have to go to negative emissions. Yes, and which of us has to do that, and when?

There is no mention whatever of who in the world is raising their emissions, and who is lowering them, and who has to do what.

This is because, absent from both Paris and Kyoto, the US is lowering its emissions. But the US is obviously the enemy of civilization on earth due to the short term focus of the finance sector, the evil of the Republican Party, right wing fundamentalism, the efforts of the tobacco denialist lobby and the Koch brothers.

China on the other hand, who leads the world in human rights and the installation of wind and solar, seems to be emitting more than anyone else, burning and mining more coal than the rest of the world put together. But China is good, whereas the US is double plus ungood.

In addition, seriously to lower emissions in the US would involve tackling the transport problem. You cannot do this without closing down the auto industry. But this is something no-one will advocate, because although their views require it, its a total turnoff.

So we cannot talk about who has to start reducing their emissions, or at least stop growing them. So we cannot talk about any sort of action. We cannot talk about what has to be done to reduce at all.

All we are left with is vague hysterical fear of the future, and lots of misuse of imaginatively presented data about past epochs. Read the comments and you will see that the commenters whose views are permitted simply echo this. The thing you will notice also is that the IPCC has become irrelevant to them. To accept the IPCC view of climate is now to be a denier. Because its not alarming enough!

Like all Ars climate coverage, its fearful hysteria. Unlike most climate forums this one doesn’t yet show the egomaniac Timmer in full flight. But it probably will before it closes.

Alley

Smart crowd at Ars.

MarkW

So intelligence is defined by abject adherence to rote learning and a complete intolerance towards any view other than the ones dictated from your masters.

At least it’s consistent with your behavior here.

Steve O

For the moment, let’s say that all the doomsday scenarios are true.

The fact is, if the ocean levels are going to rise by 40 meters, then such an outcome is inevitable and they’re going to rise by 40 meters no matter what actions we take. Labor and steel spent building windmills can’t also be expended moving cities inland. Expending all our resources in a futile attempt to manage the global climate cycle will leave us less able to adapt to the reality of it.

If what they say is true, then climate alarmists are threatening the existence of mankind with their stubborn addiction to oil, I mean to CO2 reduction.

Jeff

It has been a while since I’ve visited Ars Technica. The commenters have become even more dystopian. What a terrible lie they have adopted as their world view.

It takes time for the temperatures to get to the high level during within the MMCO range. In a thousand years it may be there. And then it will be way to late to do something about it.

william Johnston

Wooden TUITs used to be fairly common. Available in bars and other predominately male venues. Just like
the Toy Yoda given out as prizes. Some folks mis-heard the name. OOPS.

Mickey Reno

Who knew that we humans had graduated from ape-hood?

Felix

Howard Lee’s biology is no better than his geology.

Gary Pearse

Do these guys not realize that the average elevations in Greenland and Antarctica are over 2100 and 2500 m respectively. For these locations do I have to say this is above the snowline? Do I have to say that with no insolation for half a year at atime, sea ice up to 2 m thick forms and that before we can get the beginning of other than superficial and temporary melting on land, we would see icefree arctic and and Antarctic seas. This would be a reliable early warning system, so we can relax and push thoughts of calamity off far enough into the future that we have ample time to adapt as necessary. I hope this helps y’all to get a better skeep.

Ive provided a lot of help to my biology freinds trying to alleviate their neurotic worries about extinctions, crop failures, death of forests, fishes, shell fish, plankton etc. because the declining level of scholarly education and the activist political corruption of biological sciences has made me, as an old mining engineer/ geologist, somewhat more expert than they in their discipline.

Let me then help my icy friends, too, to remember a little about enthalpy, optical angles of incidence, lengths of polar days and nights, albedo and so on. The decline in their knowledge and activist corruption has even opened up a gaping void in their discipline for “feminine glaciology” to come to their rescue -a good indication of the state of their science.

Felix

In observations from the dedicated satellites, from 1979 to 2014, Antarctic sea ice grew. The decline in Arctic sea ice appears to have ended in 2012.

Right now, Arctic sea ice extent is higher than in four of the past eight years. Antarctic sea ice is in the two SD range:

http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

Maybe the sea ice early warning system is trying alert us to coming cold.