The prevailing theory (on Dino extinction) is said to be a comet/meteor strike, evidenced in the KT Iridium layer, found worldwide. This study though suggests that even though CO2 was high during the Cretaceous, it could still turn cold abruptly. Obviously a stronger forcing of some kind operated then.
Image above: more info
From a Plymouth University Press Release
Scientists identify freezing times for Cretaceous dinosaurs
Summary
Further detail
The drop is estimated to have occurred some 137 million years ago during a time when dinosaurs roamed the Earth, and would have seen the islands fall from an average of 13 degrees centigrade (ocean temperature) to as low as four degrees.
The findings, which were published in the journal Geology and featured as a highlight in Nature Geoscience, will further contribute to the debate over climate change as they appear to contradict the common model which links high levels of Carbon Dioxide (CO2) – as recorded in the Cretaceous era – with reduced polar ice caps.
Despite being located in the Arctic Circle, Svalbard was home to numerous species of dinosaur and was typically characterised by warm, shallow seas and swamps.
But the research team, led by Dr Gregory Price of the University of Plymouth, found evidence in fossils and carbonate materials preserved in marine rocks in the region of a transient shift to cooler glacial conditions around 137 million years ago.
Dr Price said: “At certain times in the geological past, the world has been dominated by greenhouse conditions with elevated CO2 levels and warm Polar Regions, and hence, these are seen as analogues of future global climate.
“But this research suggests that for short periods of time the Earth plunged back to colder temperatures, which not only poses interesting questions in terms of how the dinosaurs might have coped, but also over the nature of climate change itself.”
Dr Price, along with Dr Elizabeth Nunn, of Johannes Gutenburg Universitat in Mainz, Germany, first visited Svalbard in 2005 to collect fossils and samples, in an area famed for a number of paleontological discoveries, including giant marine reptiles such as pliosaurs and icthyosaurs.
The samples were analysed back in Plymouth and prompted return trips to the area to gather more evidence.
“The flourishing of the dinosaurs and a range of other data indicates that the Cretaceous period was considerably warmer and boasted a high degree of CO2 in the atmosphere,” said Dr Price.
“But over a period of a few hundred or a few thousand years, ocean temperatures fell from an average of 13 degrees centigrade to between eight and four degrees.
“Although a short episode of cool polar conditions is potentially at odds with a high CO2 world, our data demonstrates the variability of climate over long timescales.”
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I find this stuff fascinating… i take it from the article they haven’t inferred a mechanism yet? Id be interested in tectonic activity at the time… and since when did our current climate compare to the cretaceous period! Sounds like a lil journalistic freedom with the facts…im gonna stay away from the telegraph article! It sounds like it may give me an embolism!
Something ive always wondered about the 65mya comet strike, was if that was the cause of the massive volcanism in Indonesia… it was a big rock, and a lot o energy went somewhere(it should transmit and focus on approx opposite side o globe)
One question, if it was that warm there and no ice, where was all the water? Would’nt everything be flooded if there was no ice? Or is there more water on earth now than before?
Whatever occurred to force extinctions 137 million years-before-present (YBP), plate tectonic dispositions show Svaalbard nowhere the Arctic Circle at the time. As for the Chixculub cometary/meteorite impact in Yucatan at the Cretaceous/Tertiary (K/T) Boundary some 65 million YBP, what possible connection has earth’s inflamed oxygen-rich atmosphere then with a relatively mild, short-term, global cooling episode 72 million years before?
This ludicrous article is chronologically incoherent, geologically so far off-base that one genuinely wonders what these so-called science reporters had for lunch. Such mindless, even ridiculous, assertions are of a piece with Climate Cultists’ endless drivel basing 1,000 years of global temperatures on a magical sample of precisely three low-Arctic trees.
Here is what the world is thought to look like then:
http://www.scotese.com/climate.htm
Select “Early Cretaceous Climate”. Lots of other things on this site.
Also, the KT boundary is much like the current AGW debate. The Chicxulub crater predated the Maastrichtian-Danian contact (aka the KT boundary) by 300,000 years. To see more, search for papers by Geta Keller (http://geoweb.princeton.edu/people/keller/Mass_Extinction/massex.html).
Much as it is with the, so called, AGW debate there are those who see geological events with a peculiar slant. Think: NASA offers grants! Even more interesting the Deccan Traps are seldom, if at all, mentioned (http://www.mantleplumes.org/Deccan.html).
On a unrelated thread, look at how quiet the Sun has become! I’m thinking … Maunder Minimum just after the solar cycle peak activity … if so … next is eleven years of quiet!
The K-T is a line in the sand (now rock). Its big (sort’a), extensive, and easy to see. It also has a way of making a long and very complicated story into one that is short and sweet. Its the complicated part of the story that means it will be an item of interest for many, many years to come.
Interesting, but not sure how there is anything contradictory here, or especially revealing. It was warm, CO2 was high, and then a major global event (i.e. large comet or asteroid strike) caused a major climate change for a period of time. I don’t see must of interest of either the AGW supporter or AGW skeptics grist mill here. Barely worth my eyesight actually…
I remember some Attenborough TV series years ago, in which he explained that the ambient temperature in which a reptile’s egg was incubated determined the sex of the hatchling.
I think it was a one degree increase in temperature changed the crocodile chick from female to male (or vice versa).
At the time I thought that such a drastic increase in same sex reptiles by such a small climatic variation could have led to the extinction of the dinosaurs.
Sounds as plausible as the above theory to me, a rank amateur.
Dinosaurs were not reptiles. Birds are their descendants, not crocodiles.
If you look at this graph (link below) you can see there was cooling about when they’re talking about. They say 137 million years ago, the graph peaks it at 144, close I’d say. But look at the CO2. While it does go up before the temp drop, it keeps going down while the temp goes backup, while it flattens out and when the temp drops again. I’m no authority but it seems logical the CO2 had nothing to do with it.
Not a great graph but looks like the CO2 level then was about 21-2200 Ppm.
Explains my “duh” look when I read the article in the Telegraph stating that the greenhouse effect then was like now.
The Telegraph article about gave me a brain seizure trying to figure out why they were talking 137 and 65 million years ago. Evidently they were talking out the wrong orifice.
I’m so glad for places like this where I can attempt to resolve all the BS flying around. Thanks to all.
http://www.global-samizdat.org/Global-Samizdat/GS8-GlobalLie1/ImageFiles/GlobalTempAndAtmospheric.gif
The paper by Nir Shaviv and Jan Veizer ‘Celestrial Driver of Phanerozoic Climate’ in GSA Today, Vol 13, No 7 , p. 4 (July 2003) convincingly shows that variations of paleo-climate as seen by 18-O/16-O isotope ratios parallel variations of cosmic ray intensities, as seen by 10-Be isotope variations in geological deposits.
They also report a dominant period of approx. 130 Million years for the appearance of grand ice ages, and see fingerprints of 4 cold periods (grand ice ages) over the last 500 million years (see their fig 2). We are now in the most recent cold period. According to the authors, the variations are caused by spirals arms of the galaxy, which are traversed by the solar system. 130 million years is the time it takes to reach the next spiral arm.
So in the paper presented here, they may have seen the beginning of the next to last grand ice age period. Carbonate deposits in minerals depend on the amount of CO2 dissolved in sea water, which in turn depends on the global temperature. And global temperature may be driven by other effects but greenhouse gases.
Jan Veizer has presented this and other work on the 2nd Int. Conf. on Climate Change 2009, in New York. Maybe you can get a comment of Jan Veizer on the present work. During his tenure at Ruhr University Bochum, Germany, Veizer has been one of the leading geologists in Germany, as expressed by the prestigious Leibniz price awarded to him end of the nineties. The Leibniz price is a 2.5 million Euro award for the purpose of doing more research independent of any research grant applications.
On much shorter time scales, cosmic ray intensities are also varied by the active sun. How those cosmic ray intensity variations modify the terrestrial solar irradiation, not the one on top of the atmosphere, but on the ground via changes in the atmosphere, is shown in another paper, which I have sent to you recently. Maybe you can also get a comment by Jan Veizer or Nir Shaviv on this paper.
How cloud coverage may by varied by cosmic rays, has been discussed by Svensmark.
Of course what this suggests is that there are forcings (maybe internal to the system) which operate on a century to millennial cyclicity. So, our tiny observational window of 130 years +/- doesn’t come close to properly sampling such cycles & by definition there is no way we can tell if the increase in temps over the modern period is driven by CO2 or simply natural forcings. I can’t emphaisze enough how important that is – all we really have is a general correlation of CO2 & temps in the modern period, but on the basis of observation alone, knowing there are natural cycles of considerably longer length, it is SCIENTIFICALLY INVALID to conclude the the change in temps in the modern era is from CO2.
If you are thinking as a scientist, this paper is as much a dagger in the heart of AGW as any thing you could imaging.
Of course, most of us geoscientist types have been saying this all along – based on careers of making observations similar to this paper. This is a primary reason that you will see that most geoscientists are AGW skeptics.
If this story is correct then it presumably supports the argument for higher values for climate sensitivity, rather than lower ones, which is precisely why anthropogenic influences hold the potential for substantial global climate change.
There were several cooling events between 195 Mya and 135 Mya with the largest cool period/mini-ice age ocurring at 160 Mya.
http://img196.imageshack.us/img196/8615/allpaleotemp.png
http://img155.imageshack.us/img155/44/detailedphanerozoictemp.png
These cooling events seem to be associated with the continental drift of Siberia/East Asia across the North Pole.
http://www.ig.utexas.edu/research/projects/plates/images/150Ma.jpg
But between the Triassic-Jurassic extintion event about 200 Mya (associated with the beginning of the cooler periods), there were very, very few extinctions until the Cretaceous-Tertiary extinction event at 65 Mya.
http://en.wikipedia.org/wiki/Extinction_event
The climate actually warmed considerably after the last cool period of 135 Mya so that the Cretaceous Warm period at about 100 Mya was one of the warmest in history.
So, this study just confirms there was a cooler period about 137 Mya. Svalbard was just north of Greenland at about 60N at the time and Europe and Greenland/North America were still locked together.
I have not yet read the comments but i have a question.
Q) Do the IPCC models incorporate melting polar icecaps resulting in cooling prior to a resumption in ‘warming’ later?
Fitzy (15:01:04) :
SetSatire=True
No Scientist Magazine – April 26 2010.
AGW effects have been shown to “Leak” through high energy experiments, causing past geological warming events, such as those that killed the Dinosaurs.
The Large Hadron Collider (LHC), may have chanelled global warming into the past, via some ‘Dark Energy’>>
Now hold on. If it leaked into the past it went somewhere else. The earth wasn’t in the same place then as it is now. So any AGW we leaked into the past would’ve missed. The obvious explanation is that some other race on some other planet vented THEIR heat into THEIR past and killed OUR dinosaurs. This is awful. They could do it again at any moment! We need to start preparing. Research. Training. Develope defenses and a counter attack. We need to find the aliens that murdered our dinosaurs and make sure we get them before they get us. It all makes sense now. They may have already started their attack, there’s four times as many polar bears as there were 20 years ago and they are going extinct! PROOF OF ALIEN ATTACK! We must protect our polar bears, ourselves, and avenge the dinosaurs! The UFO’s are real, they are scouts checking to see if we are extinct yet.
Gotta go, wife says time for meds and something about wrapping my head in tinfoil.
Lots of interesting discussion here. The K-T boundary was terrestrial in origin, and it was not. Svalbard was in the arctic, and it was not.
What this proves to me is how ridiculous it is to ever state that “the science is settled”, except maybe in some aspects of physics and chemistry. The discussion on this topic shows just how diverse the theories are, even for events which have some good, directly measurable evidence (isotope levels, etc.). The whole AGW debate has pushed me to reconsider many assumptions I’ve made based on the bulk of scientific evidence. Heck, look at how many things we just KNEW were true in the 1970’s that are now false due to better measurements or data (thinking astronomy, in particular).
I now see science more as a continuum, and theories slide along the line between total bunk and absolute fact, based on the current state of evidence.
It used to amaze me how much we know about dinosaurs, considering we’ve never seen one. As far as I know, the only evidence we have are fossils, which are rock that formed where bones used to be. So, we have a proxy for the skeletal remains for critters that lived a minimum of 65 million years ago. How do we know if they were warm-blooded or cold-blooded? How do we know they didn’t have lungs like a modern reptile? No soft tissue exists so there is no way to really know…we can only infer from the limited evidence we have. I’m much more jaded now about what we think we know and often pass off as fact. In reality smart people make guesses, publish them, and they become the prevailing “fact” until someone else publishes a different idea that sounds better. Sometimes there are conflicting ideas that both match the available data.
From what I remember, this is the way science is supposed to work. I think the breakdown, which is certainly not unique to AGW, happened when theory began to be sold as fact for the purpose of collecting government grant money. Sometimes it is hard to tell whether you are reading science or a marketing pitch.
Roy Spencer will be interviewed tonight (Mon.) on Coast-to-Coast from 10pm to 2am Pacific time.
[Reply: Do you have a link? ~dbs]
John Silver (13:24:29) : “No one knows the number theories there are to explain the extinction of the dinosaurs. Every “scientist” have at least one. It has been like this for as long as I can remember.”
I’m partial to the oxygen reduction theory. If terrestrial atmospheric O² went from 30% to 20%, it would be easier for smaller animals to survive: roughly speaking, airway area is proportional to animal height squared; air requirement is proportional to animal height to the third power. Smaller is better.
New Brunswick Barry (12:56:33) : “…I thought the latest speculation was that the dinosaurs were warm-blooded, not cold-blooded.”
See Professor Waxman on the subject. Bottom right.
http://www.pulse.org.za/pulse/farside.html
And birth is the leading cause of death.
Anyone give any credence to this theory?
“The Deccan Traps, a “volcanic flood,” buried huge portions of India underlava about one mile deep over an area half the size of Australia.But that wasn’t all. According to paleontologist Dewey McLean, a good portion of the Deccan Traps was submarine.
Wouldn’t it make sense that thousands of cubic miles – cubic miles! – of lava measuring 2,150 degrees hot, ten times the boiling point. pouring into the seas might have heated them just a tad?
That’s exactly what happened. Ocean temperatures at the dinosaur extinction rose by 14F to 22F. As the lava poured into the seas, te oceans must have boiled, literally boiled, sending untold amounts of moisture into skies. The increased evaporation would have sent excess moisture rose into the skies, skies which had already cooled because of the ash from the above water eruptions. This lead to massive increases in snowfall, and to an ice age.
Warmer oceans and colder skies, a deadly combination . . . which is what I propose in Not by Fire but by Ice.”
jorgekafkazar (19:40:20) : it is actually thought that oxygen levels rose after the KT. They were probably relatively low throughout the Mesozoic (from 35% peak in the Carboniferous-Permian to about 10% in the Triassic), apparently staying below 20%. Dinosaurs likely adapted to this by having a more extensive and efficient respiratory system, as evidenced by that in birds today. Oxygen increased after the KT and probably allowed mammals to compete more successfully.
Love the elegance of Neal Adams’ dinosaur extinction theory. Simply put, the dinosaurs were land egg layers that migrated pole to pole. Once the land migration pathway was severed, the dinosaurs died. Not the other species like crocs. They didn’t migrate.
My (non scientist) 2 cents.
Aiui, the Earth’s tilt changes on a 41,000 year cycle, so the Arctic Circle has
grown and shrunk some 2,000 times in the last 82 million years.
(My theory being that the world has less ice when it’s upright.)
Inconceivable!
The the AGW Scientists repeat their made up half truths the more they believe them themselves.
Inconceivable!