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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Re: Ian Mc Vindicated (12:20:12)
Stop crying in your beer. Your tone reads more like the human hating claptrap on RC.
Michael
One of the reasons why I like the internet is that when someone comes out with an article like this, the response is immediate and informed. There is no way to respond to the Telegraph article.
Oh I forgot one thing. Dinosaurs were almost certainly not “cold-blooded”, at least the theropods (carnivorous dinosaurs) were definitely warm-blooded, and other groups probably were too. Incidentally they did live in areas near the poles where temperatures were definitely below freezing in winter (e. g. southern Australia, northern Alaska), and where poikilothermic (“cold-blooded”) forms like crocodiles and squamates (“lizards) apparently could not survive.
“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.
Lucky there wasnt a runaway tipping point then.
hehe
There was a compendium issue of palaeontology in the Anatomical Record in 2009 which included a fascinating paper by Edith Schachner showing that dinosaurs had lungs with a one-way through air circulation like birds, in contrast to the tidal air circulation that we have. The bird / dinosaur one-way system, which employs air sacs in bones, is TEN TIMES more efficient than ours. Bird lungs dont move out and in like ours with breathing. They have a rigid shape, and are smaller than ours relative to body size. But their much greater efficiency allows them to accomplish the aerobic feat of flying long distances, impossible for mammals.
That dinosaurs also had these bird-like lungs (birds are of course dinosaurs, the surviving or crown group) means that they literally would have RUN RINGS AROUND any mammalian ancestors that they encountered. The more agile ones like the struthiomimids and raptors would probably have run indefinitely without tiring. Thus our thecodont ancestors had to sit out 150 million odd years as nocturnal rats waiting for the dinosaurs to go away.
Our ancestors had to sit through three or four mass extinctions in fact before our moment came. The biggest was the Permian-Triassic, a heat event. Flood basalt eruptions in Siberia realised the wildest AGW dream-nightmare of catastrophe, with prolonged massive volcanism and atmospheric discharge resulting in warming leading to catastropic ocean anoxia, almost total extinction in the sea and 80-90% on land. However two groups that survived, Therapsids and Thecodonts, developed into the dinosaurs and (eventually) mammals respectively. The dinosaurs were well heat adapted, especially with their efficient lungs. So the mammalian precursors lost out but did not die out.
The next catatrophe was also a heat event, the Triassic – Jurassic, basically the start of the separation of America from Europe-Africa, and the opening up of the mid-Atlantic ridge. Again big-time volcanism, acute warming. Again the dinosaurs did well. (But we held on.)
However During the cretaceous, a general cooling started. Also there were cold snaps (as the dinosaurian BBC would have called them) such as the one described in this article from Plymouth. This began to stress the dinosaurs who preferred it hot. This may be one reason why some dinosaurs tended to larger size in the Cretaceous like T Rex. (Although sauropods were big in the Jurassic). So some good news for the rat-like mammals-in-waiting.
Then came the end-Cretaceous disaster, the Chikxulub meteor impact. Finally a cold event extinction. The dinosaurs perished except the dinosaurian ancestors of the birds. Mammals with their fur and thermoregulation survived, and, following brief competition with some monster-chicken like bird predators, emerged finally as the dominant land animals.
Climate continued to cool in the Tertiary further playing to mammals’ advantages. Eventually the current glacial period developed (landmass surrounding a north polar sea).
But if AGW is correct and CO2 release reverses 200 million years of cooling, then maybe the tide will turn again? Perhaps the birds will evolve back into dinosaurs?
A major physiological advantage of dinosaurs over say humans relates to playing the organ. A human organist has a balance problem, he uses feet for the pedal bass notes and hands for the keyboard,and leans forward with no counter-weight. A dinosaur, realising development toward bifocal eyes, opposing thumbs and intelligence etc.. (e.g. Struthiomimus, Compsognathus etc.) would not have this problem. The leg and arm claws, though fewer in number (3-4 rather than 5) would still play the pedals and keyboard effectively, and the tail would counter-balance the whole organist. Thus the complete realisation of Bach’s musical creativity awaits this significant climate warming and consequent re-adjustment of life-forms.
The opening paragraph of this article seems at odds with the body of it. The opening begins “The prevailing theory (on Dino extinction) is said to be a comet/meteor strike.” But the remainder talks about a cooling event that occurred 70 million years earlier that the Dino extinction.
REPLY: I’m just pointing it out so people would get the two epochs confused, didn’t work, no good deed goes unpunished. -A
The KT iridium layer was long ago shown to have its source in terrestrial volcanism not extraterrestial meteors. The meteorite extinction theory is just one of several examples of junk science made popular by what passes for science journalism. The same journalist who have been pushing AGW cut their teeth promoting the ME theory.
What’s the estimated measurement uncertainty on that 137 million years? It strikes me as being fairly close to the 142-million-year-old date of a big Australian impact crater, known as Gosses Bluff. Did that impact cause significant global cooling?
http://en.wikipedia.org/wiki/Gosses_Bluff
Could anyone explain to me the reasoning behind CO2 feedback effects? We’re living with around 350-400ppm CO2 right now. CO2 levels 50m years ago are estimated to have been anywhere between 500-2000ppm. Surely if the rapid rise in global temperatures we see now as a result of CO2 ‘forcing’ applied then – on the same timescale we allegedly see today – earth would have suffered ‘catastrophic warming’ and become a fireball within a geological blip. The only answer I’ve heard to this question from AGW proponents is that the sun was ‘dimmer’ 50m years ago, with no explanation as to why it was dimmer, how much dimmer it was or how solar output 50m years ago can be measured. Regardless, solar output was obviously high enough to propel the earth to temperatures exceeding those of today so why didn’t high levels of CO2 in the atmosphere force them onwards and upwards? Has the earth been delicately balanced on a knife edge of energy equilibrium throughout geological history, where every energy variable just happens to have been countered by another to conveniently ensure the survival of life? Or could it be the fact that we have an atmosphere at all is down to the predominance of negative feedback effects of CO2 / water vapour / oceans, regulating global temperatures in both directions?
Apologies for any mistakes or incorrect assumptions here – I’m no expert, just interested to hear people’s thoughts.
Bob(Sceptical Redcoat) (12:05:23) :
I don’t know why, but I’ve always suspected that transitions from warm to cold (including ice ages) occur quickly, in the order of one or two centuries at most. In contrast, the reverse happens over periods of thousands of years.
Other way around: warming is fast, descent into cold is slow.
Bruce Cobb (12:59:10) :
Dumber than a box of hammers, two boxes of bent nails and 2 bashed thumbs.
Les Johnson (12:11:43) : “The Telegraph has a much different take on this. They actually state that high CO2 levels caused melting ice, which caused the cooling.”
Ah yes, the old “heating causes cooling” argument. Favored by doomsday fans of The Day After Tomorrow, and doomsday capitalists such as Al Gore.
@Bruce Cobb (12:59:10) :
You mean dumber than rocks?
Ian Mc Vindicated (12:20:12) : “This whole idea of AGW global warming is so proposterous I am surprised it is getting nothing more than a chuckle. ”
The core religious conviction of the CAGW believer is solipsism.
While I make no claims as to the veracity of their map (thank you Google), according to this paper Svalbard was sitting at about 65 deg north at 120Ma which does indeed put it in the geological ballpark of the Arctic Circle during the time frame in question (scroll down to map on second page):
http://www.nhm.uio.no/forskning-samlinger/studier/geologi/svalex/ressurs_CD/Misc/Hurum_et_al_NJG_2006_dino-footprints.pdf
Seems that if Svalbard wasn’t quite at the Arctic Circle then it would be short something on the order of magnitude of hundreds of miles, not thousands.
Here is a nifty reconstructed globe for those that like 3D (Svalgard can be spotted off the north coast of Greenland):
http://www.scotese.com/1202d.htm
As for the Gulf Stream question – the north Atlantic hadn’t unzipped at 137Ma so the current didn’t exist as we know it today.
~Geologist Deb
OT:
Merkel frustrated…
http://www.spiegel.de/international/germany/0,1518,691194,00.html
A number of years back I was working a few meters above the KT in West of Edmonton, AB. I over drilled and cored a few holes to penetrate it. Passing that core along to the Paleontologists. If I remember correctly they told me the climate as represented by the pollen grains indicated much stress. That would be in ±1 m just below the KT. That stress was a changing climate but I don’t think they attempted to tie it any global event. Lots of volcanic ash associated with these rocks as well.
There is very little evidence correlating CO2 to temperature over geologic time though there are frequent assertions of CO2 driven climate forcing in the Phanerozoic. These generally appear to depend upon choosing sample periods when the apparent trend are in the same direction. Cherry picking as it were.
The end of the Cretaceous not only corresponds with the iridium horizon but also with a shift from a “greenhouse” to “icehouse” state though the shift is usually placed later in the Paleogene (about 50 mya). The distinction between the two types of climate regimen is presence or absence of evidence for polar ice caps and ice rafting of glacially transported rock into marine basins. Earlier in the Mesozoic the climate was also warm without any evidence for increase. A mid-Mesozoic “ice house” event spanning the late Jurassic and early Cretaceous interrupts this in the late Jurassic-early Cretaceous. This event lacks known evidence of continental glacial activity (no tills or other markers) but does yielded evidence of ice rafted rock as far south (and north) as 60 degrees latitude. All it takes is an examination with MK I eyeball to notice that there is no correlation with CO2 levels. In fact, while it has oscillated pretty wildly, CO2 seems to have tended to steadily decline in concentration since the middle Mesozoic. The present era marks the apparent lowest concentration in geological history.
Shaviv and Veizer 2003 provides a nice composite graph of the available geological data that is useful regardless of how one regards their solar/cosmic ray hypothesis. I had to produce my own graph of the same data and theirs is nicer.
http://www.juniata.edu/projects/oceans/GL111/celestialdriverofclimate.pdf
http://iceagenow.com/Cold_killed_the_dinosaurs-Reader_trashes_researchers_claim.htm
Well one thing we know from a week or so ago is that meteorites take no more than 35 seconds or so to go from space to earth; and deposit their Iridium, so we can make hard fountain pen nibs.
From that moment on; would it take a few weeks or maybe as long as a year for all the dunnosirs to starve to death. So why did the mammals survive.
I’ve read credible scientific articles that the demise of the dinosaurs was going on for something like a million years before that 35 second blast and this is the very first time I have read that NO non flying dynos survived after the earth got sealed in iridium.
So anecdotally, it seems to me that the meteor event was a lucky happenstance that just came along at the right time to take the blame.
Not that I’m saying that I don’t believe the Alvarez thesis; its just it took those ugly monsters to damn long to croak, if you ask me.
The cold spell I can believe as more fitting the time it took to fade to dunnosir black.
There must have been several massive volcano eruptions and meteor strikes over the long period the dinosaurs ruled the Earth. All would have had caused sudden climate cooling events which could threaten their survival.
Perhaps I’m missing something, but what’s new here?
RockyRoad (12:42:45) :
“Climate change to the earth is analagous to navel gazing to a human–simply no big deal; it comes with the territory.”
I had to re-read this. First time I thought it said naval grazing. I’m not eating belly button lint.
well, yes, of course. The sun was 30% dimmer back then than at present. Also, with more ocean surface area, evaporation was greater so cloud cover and thus planetary albedo was higher.
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 effect’, the evidence can be found in the layer of Iridium, that demarks the KT Boundary, the point in time when the big lizards snuffed it.
The change in the Earths albedo, due to more clouds caused by LHC AGW, 140 million years ago, also caused big rocks to fall from the sky, these in turn caused an ice age event. Which wiped out most life (see hockey stick graph)
Scientists recommend we shut down the 21st century, in order to spontaneously resurrect the dinosaurs, which will have huge economic spin offs for Kentucy Fried Chicken – Mega Family Dinner Buckets, solving world hunger over night.
Al Gore has called for a national day of mourning, for the billions of life forms killed by future mankind in the extremely distant past, “Thats the difficulty people have, grasping that we changed the planet before we existed, but the proof is in a convertable.”
Dinosaurs being essentially avian, with feathers and down, could handle more weather than the traditional swamp monster image. Think of the ptarmigan. I certainly wouldn’t rule out migration, and species today are quite capable of moving their ranges over a period of hundreds or thousands of years, if not far quicker.