From the University of Leeds , 250 million year old certainty where there was none before, now megasized.
Tropical collapse caused by lethal heat
Extreme temperatures blamed for ‘Dead Zone’
Scientists have discovered why the ‘broken world’ following the worst extinction of all time lasted so long – it was simply too hot to survive.
The end-Permian mass extinction, which occurred around 250 million years ago in the pre-dinosaur era, wiped out nearly all the world’s species. Typically, a mass extinction is followed by a ‘dead zone’ during which new species are not seen for tens of thousands of years. In this case, the dead zone, during the Early Triassic period which followed, lasted for a perplexingly long period: five million years.
A study jointly led by the University of Leeds and China University of Geosciences (Wuhan), in collaboration with the University of Erlangen-Nurnburg (Germany), shows the cause of this lengthy devastation was a temperature rise to lethal levels in the tropics: around 50-60°C on land, and 40°C at the sea-surface.
Lead author Yadong Sun, who is based in Leeds while completing a joint PhD in geology, says: “Global warming has long been linked to the end-Permian mass extinction, but this study is the first to show extreme temperatures kept life from re-starting in Equatorial latitudes for millions of years.”
It is also the first study to show water temperatures close to the ocean’s surface can reach 40°C – a near-lethal value at which marine life dies and photosynthesis stops. Until now, climate modellers have assumed sea-surface temperatures cannot surpass 30°C. The findings may help us understand future climate change patterns.
The dead zone would have been a strange world – very wet in the tropics but with almost nothing growing. No forests grew, only shrubs and ferns. No fish or marine reptiles were to be found in the tropics, only shellfish, and virtually no land animals existed because their high metabolic rate made it impossible to deal with the extreme temperatures. Only the polar regions provided a refuge from the baking heat.
Before the end-Permian mass extinction the Earth had teemed with plants and animals including primitive reptiles and amphibians, and a wide variety of sea creatures including coral and sea lillies.
This broken world scenario was caused by a breakdown in global carbon cycling. In normal circumstances, plants help regulate temperature by absorbing Co2 and burying it as dead plant matter. Without plants, levels of Co2 can rise unchecked, which causes temperatures to increase.
The study, published today [19 October 2012] in the journal Science, is the most detailed temperature record of this study period (252-247 million years ago) to date.
Sun and his colleagues collected data from 15,000 ancient conodonts (tiny teeth of extinct eel-like fishes) extracted from two tonnes of rocks from South China. Conodonts form a skeleton using oxygen. The isotopes of oxygen in skeletons are temperature controlled, so by studying the ratio of oxygen isotopes in the conodonts he was able to detect temperature levels hundreds of millions of years ago.
Professor Paul Wignall from the School of Earth and Environment at the University of Leeds, one of the study’s co-authors, said: “Nobody has ever dared say that past climates attained these levels of heat. Hopefully future global warming won’t get anywhere near temperatures of 250 million years ago, but if it does we have shown that it may take millions of years to recover.”
The study is the latest collaboration in a 20-year research partnership between the University of Leeds and China University of Geosciences in Wuhan. It was funded by the Chinese Science Foundation.
For more information:
‘Lethally hot temperatures during the early Triassic greenhouse’ by Yadong Sun (University of Leeds and China University of Geosciences), Michael Joachimski (University Erlangen-Nurnberg, Germany), Paul B. Wignall (University of Leeds), Chunbo Yan (China University of Geosciences), Yanlong Chen (University of Graz, Austria), Haishui Jiang (China University of Geosciences, Lina Wang (China University of Geosciences) and Xulong Lai (China University of Geosciences) is published in Science on 19 October 2012. For a copy please view the web page http://www.eurekalert.org/jrnls/sci/ or contact the Science press team, phone +1 202-326-6440 or email scipak@aaas.org
For interviews please contact Esther Harward, University of Leeds press office, phone +44 113 343 4196 or email e.harward@leeds.ac.uk
lol
Of course, you could also claim that when the world is warmer there are more species to go extinct due to other causes. The last time I checked, there have been precisely zero recorded mass-extinctions on cold planets like Jupiter…..
So, are they saying that the Sun went through a very active millions of years?
Geocarb IV, I believe, has the planet topping out at 22 deg C, typical of a warm body operating by thermodynamic principles in response to a heat source, the Sun. How does their physics handle a much hotter body obeying the Stefan-Boltzmann law? Something is wrong or missing here, but CO2, or any gas, can back radiate this kind of power. The upper troposphere would have to be at 1000s of deg C to even have the energy supply to heat the surface to this temperature, let alone the time. Days were shorter then, too.
As CO2 cannot do what they say (remembering that Venus is so hot, not because of 95% CO2, but due to 90 atmospheres of gravitational work being done on the atmosphere) and these reported temperatures go against thermodynamics, methinks they need to go back and start over.
As calcium carbonate is less soluble in warm water than cold, there would have been rampant deposition going on as calcium leached to the waters and the seas and concretions would result. CO2 would probably not have been all that high, indicated in other works as rising from a very low state, which probably correlated with the actual extinction, at about 2000 ppm and then decreasing to about 1200 ppm CO2.
They pay no attention to the very unusual 30 million years of cold and CO2 at a dangerously low 250 ppm, starting 20 million years BEFORE the cold spell and persisting throughout the cold spell, that preceded this ramping up of temperature and CO2. It’s pretty clear that we have little idea of what was happening in this period.
Nope, it had to be CO2 and not 30 million years of record LOW temperatures. “Please, sir, can we have more funding?”
So they ignore all the places where its very hot and there is life such as near hydrothermal vents and Death Valley and where does this massive CO2 get produced from very little few animals.
Given the position of the land masses as shown it looks like the hot water just swirled around in the big bathtub-like area in the middle and the heated water couldn’t flow up to the poles. In our current configuration, the ‘bathtub’ of the Carribean is open at the top and bottom instead of closed in like the basin seen in the illustration.
What broke the heat wave; a crack in the wall of the landmass? That’s my guess.
So they’re trying to blame the temperature on the CO2? What if the continental configuration of the Pangaea continent was responsible for the temperatures – and the CO2 would be a consequence, not a cause?
According to the wikipedia, CO2 levels were not extraodinarily high.
http://en.wikipedia.org/wiki/File:Phanerozoic_Carbon_Dioxide.png
“Sun and his colleagues collected data from 15,000 ancient conodonts (tiny teeth of extinct eel-like fishes) extracted from two tonnes of rocks from South China. Conodonts form a skeleton using oxygen. The isotopes of oxygen in skeletons are temperature controlled, so by studying the ratio of oxygen isotopes in the conodonts he was able to detect temperature levels hundreds of millions of years ago.”
First they say everything died but they had no problems finding conodonts? How did the fish survive to form teeth to record the temperature when everything died?
I’ve commented on this before. During the hottest periods of Pangea (265 Mya, not 251 Mya during the Permian extinction), temperatures rose to +10.0C and it probably got too hot for complex life in the Paleo-Thethys sea on the eastern side of Pangea.
Now part of this is because it was a relatively shallow, enclosed sea on the western side of the then very large Pacific at the time. The trade winds would have blown the warm equatorial waters across the Pacific into the Paleo-Thethys and just like the ENSO operates today, there would have been periodic ENSO-like spikes in the ocean there (something like the Pacific Warm Pool is today).
So, shallow, enclosed sea, western-side of the Pacific – temperatures would have sometimes got to +14.0C compared to today’s maximums in this area of 32.0C. ie, Very hot ocean. There is evidence of large sea life die-offs during this time but it is as much related to geography as it is to anything else.
The Permian Extinction, happened later when temperatures fell by up to 8.0C and it was caused by the Siberian Traps volcanoes. A new study published recently shows this point.
http://phys.org/news/2012-10-geochemical-analysis-chinese-permian-triassic-mass.html
http://geology.gsapubs.org/content/40/11/963.abstract
No, oxygen isotopes in skeletons are NOT temperature controlled. The isotopes in precipitation are DEW POINT controlled. And that essentially voids all temperature conclusions from d18O and d2H.
Please read this.
https://dl.dropbox.com/u/22026080/non-calor-sed-umor.pdf
Andre
Hate to have to point out the bleeding obvious, but there aren’t a lot of species living in Death Valley either!
Oxygen isotope ratio’s relation to water temperature is presumably being extrapolated here since we don’t have anywhere on Earth to collect the calibration data for 50 -60 C sea water.
Also authors don’t seem to know a shark when they see one to judge from that labels under the icons in the figure.
“This broken world scenario was caused by a breakdown in global carbon cycling. ”
Oh, so they have solved one of the most persistent problems Earth’s history, what caused the mass extinctions. CARBON. We should have guessed really.
Still, scary stuff, uh?
you mean there was, like, natural global warming?
http://blogs.24.com/henryp/2012/10/02/best-sine-wave-fit-for-the-drop-in-global-maximum-temperatures/
amazing
The essence of skepticism is to not be too ready to believe a claim, while not being so intellectually dishonest as to deny evidence.
In order for me to find this plausible, they would need to answer many questions.
We are assured that levels of CO2 and heat much lower than that reported will prevent the formation of shellfish shells and corals. If the reported shellfish did have shells, is there an explanation for this apparent contradiction?
Does geochemical evidence confirm that there are not other causes of the isotope readings they report? Was there a ‘nearby’ supernova, and if so would that explain their results? Were their samples taken from a region with high natural radioactivity, and might that influence their results? Does other geochemical evidence support the ‘ultra-high CO2’ theory?
Do plant fossils from outside the ‘dead zone’ exhibit adaptation to high CO2?
I’d like to see replication of their results using other instruments.
They are not questions that impact on their measurements, but I’d be interested to know their judgment on the following issues: What do they consider to be the ‘tipping point’ for this temperature flip? How quickly do they think the temperature changed? Why do they think natural selection did not cope with the change? What were the arrangements of the continents and Ocean currents 250 million years ago? What was the physical basis of the earlier assumption that ‘sea-surface temperatures cannot surpass 30°C’ that they report, and why do they believe that did not apply?
Do they speculate as to how the high temperature regime ended?
“but this study is the first to show extreme temperatures kept life from re-starting in Equatorial latitudes for millions of years.”
and
“Without plants, levels of Co2 can rise unchecked, which causes temperatures to increase”
and then:
“No forests grew, only shrubs and ferns. No fish or marine reptiles were to be found in the tropics, only shellfish”
Don’t shrubs and ferns absorb CO2? Don’t shellfish count as life?
Then again, they could be wrong, with bold statements about carbon dioxide causing global warming! So, in fact, no real improvement of casues & attribution as far as I can see! Ho hum. Do I detect a puter model somehwee buried in the debris???
Hmmm:
Sun and his colleagues collected data from 15,000 ancient conodonts (tiny teeth of extinct eel-like fishes) extracted from two tonnes of rocks from South China. Conodonts form a skeleton using oxygen.
Fishes?
Then how could they grow to leave their teethe when in the same breath:
It is also the first study to show water temperatures close to the ocean’s surface can reach 40°C – a near-lethal value at which marine life dies and photosynthesis stops.
Some sort of oxymoron, but as I have no access to the paper I will wait for those who have.
Strange thing is, historical records of CO2 concentrations which show a sharp increase 250 millions years ago do not suggest any sharp decrease 5 millions years later. Apparently Earth somehow managed to recover without CO2 concentrations reduced.
http://en.wikipedia.org/wiki/File:Phanerozoic_Carbon_Dioxide.png
Or perhaps there were more factors involved than CO2….?
So is this paywalled? Without reading the paper, is this a Mannian trick? Find a proxi that seems to say hot but only use the teeth from a certain region and a certain animal and then only the ones that come with a hockey schtick? We can’t know unless the paper is available for public review. Was it paid for by us? Or was it privately funded with private cash from private citizens? Loved the plug for interviews at the end of the press release.
It concerns me that Ph.D.’s were awarded. How many rode into the Ivory Tower on this paper?
Let me see, they know the land temperatures because the teeth of sea creatures… Right.
There are places in the Atacama desert today that doesn’t even have bacteria.
How does this zone differs from the desert zone of today, Sahara, Arabian Desert and so on?
The findings of this publication are very interesting, however we should be more concerned now about how treat the whole issue of Climate change. in some of the African countries critical temperatures have been, Chad recording a maximum of 47.6 °C in 2010, Algeria recording the highest temperature ever recorded since 1931 in Africa with 51.0 °C in 2011. We are not very far from reaching lethal temperature, the question is how long until we cross that line. I really think that this is a great work of Science and it can go a long way in helping us understand Climate change and take appropriate actions to minimize the impact.
“Until now, climate modellers have assumed sea-surface temperatures cannot surpass 30°C.”
Why on earth would anyone think that?
http://en.wikipedia.org/wiki/Fran_Crippen
And don’t universities teach students to justify their assumptions any more?
Mike.
Anyone who is in the know on this issue accepts that it was aliens – just watch the movie “Battle: Los Angeles” to see how thorough they can be regarding destruction of the environment /sarc
“Nobody has ever dared say that past climates attained these levels of heat.”
I attribute that absence to there being no empirical evidence to support the “dare,” but seemingly, any “climate scientist” can create a computer simulation today and assert “x” as being real with impunity. But if it’s dares that make “science” today, then I’m asserting it was aliens that influenced the heat – humanity or its progenitors were not around to add the anthropogenic signal; therefore, it must have been a xenopogenic influence. I have no empirical evidence to support the assertion, but nobody has ever dared say that past climates attained these levels of heat due to alien influence.
Btw. in the Persian Gulf sea surface temperatures of up to 36 degrees have been measured, and land temperatures in the area have exceeded 50 degrees, so it’s not all that different.
How are the isotopes of oxygen in skeletons “temperature controlled”? Not doubting; just asking.
/Mr Lynn