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
My pet theory is that a meteor punched through the Earth’s crust, opening the SIberian Traps. I’d expect that the thermal energy from 2 million km² of exposed lava would tip the balance a bit more than an equal number of SUVs.
Are they BS us? They talk about temperature but the don’t mention Siberian Traps and devastating volcanic polution? Perhaps it is hidden in plain sight.
Where was the runaway warming?
Um are they suggesting that elevated CO2 was the cause or merely an effect of that warm period 250M years ago?
Was the devil CO2 wreaking havoc back then too?
Scientists have discovered why the ‘broken world’ following the worst extinction of all time lasted so long – it was simply too hot to survive.
No it wasn’t. Even if you buy the conclusions of this study, that is not what they say. What they say is that heat in the tropics led to reduced biodiversity in the tropics. They call this a “dead zone”, while discussing the shrubs and ferns and mollusks that lived there.
By that very same criterion – reduced biodiversity due to temperature – our current polar regions are “dead zones”. Much deader than the tropics these guys describe – there aren’t any shrubs in Antarctica. Conversely, the polar regions were allegedly where all of the life was 250 MYA, due to the “extreme heat” that made those areas livable.
How many millions of years is it going to take for the earth to “recover” from the current “dead zones”? Is there anything we could do to add some heat, to hasten that process? Hmmmmmm….
If the authors want to make a statement like that, they have to put it in context. The CO2 level at the end of the Permian was about 2000 ppm. Later, during the Jurassic, it was higher. Earlier, it was much higher. During the Cambrian, life was plentiful (ie. Cambrian explosion) with CO2 at around 7000 ppm.
On the face of it, the paper is risible.
early climate
timeline of life
“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.” Something is wrong with this statement. This study appears to link “global warming” to the unusually long recovery period, but not the mass extinction itself. Now, I’ll buy the theory that extreme temperatures kept life from re-starting. But what caused the extreme temperatures? What killed the plants? If the researchers are attributing all this to “carbon”, where did it come from? And what was the “carbon” level? My BS antenna are up.
Did CO2 case warming, or did warming cause CO2? The author’s says that CO2 caused the warming, but doesn’t provide any evidence beyond correlation to support their conclusion. This is faulty logic, because it is well established that correlation does not show causation.
As such, the conclusions are un-scientific. The paper assumes CO2 us the cause; it does not show CO2 is the cause. We already know from ice cores 10+ years ago that higher temps increase CO2, as it out-gasses out of solution in the oceans. The problem is that most climate scientists do not take this out-gassing into account in their work, because the ice core findings only came out after they put their textbooks down and started writing papers.
Pray tell why did the carbon cycle suddenly break down? No mention of the underlying cause, did the plants go on strike?
Co2 and temperature over geological timescales. Find the correclation if you can. 😉
http://www.biocab.org/Geological_Timescale.jpg
https://stevengoddard.wordpress.com/2010/12/13/geologic-record-shows-no-relationship-between-temperature-and-co2/
I’m trying to square this circle.
They point to higher temperatures as killing off plants and thus allowing CO2 to build up.
But at the same time they are pointing to higher levels of CO2 as causing the heat build up.
How can higher levels of CO2 be both the cause and the effect of the heat build up?
PS: Plants outside the “dead zone” didn’t die, and would have flourished in a warmer world with more CO2 in the atmosphere. Even if all the plants in the “dead zone” had died (and according to the authors, they didn’t), then the plants living in the rest of the world would have been ready, willing, and able to absorb the extra CO2. All other things being equal.
In a few hours, readers here have literally eviscerated this paper! How does this stuff get published?
Ironically, the idea that turns this paper into complete garbage is likely the very same idea that guaranteed it would be funded and published:
“This broken world scenario was caused by a breakdown in global carbon cycling.”
It appears that climate science is now completely run by the Joseph Goebbels Foundation.
50c plus would certainly be damned hot but let’s take a look at a warm period in the past and hot a tropical region of the Earth reacted.
Apparently the debate is now over.
collected data from 15,000 ancient conodonts (tiny teeth of extinct eel-like fishes) extracted from two tonnes of rocks from South China.
Why am I reminded of one tree at Yamal?
I’ll take this study as ONE data point. At this point, at this time, it was unusually hot. But we are a long way from cause and effect at world-wide scales.
No doubt that the Carboniferous to Permian to early Triassic is a time of intense climate change.
http://en.wikipedia.org/wiki/File:Phanerozoic_Climate_Change.png Something had to happen to create the world largest mass extinction event (which is why we have a Permo-Triassic division). We went from huge coal accumulations to glaciation to a hot spike (?in the middle? of the Permian) to extensive desertification (from tectonic configurations?) to a recovery of animal life in the Triassic. Behind all this is the question, what was sea-level atmospheric pressure back then?
But as Anthony pointed out, there is a lot of uncertainty about. The paleogeography of the NeoTethys is pretty sketchy. Did these two tons of rocks come from a restricted sea? Remember, the Gulf of Mexico in Jurassic time was a place where huge amounts of Louann Salt accumulated from evaporating sea water.
Just to be clear on a point… Oxygen isotope ratios are linked to the temperature of the animal in which the bone is growing, or more precisely the temperature of the water the animal uses to grow, and assumes that fossilization has not changed Oxygen ratios via replacement at depth. These are not a proxy for world-wide temperature, not in the same way that atmospheric levels of Carbon-14 can point to cosmic-ray intensity.
“No fish or marine reptiles were to be found in the tropics,…….”
I remain sceptical of this claim. Deeper in the ocean should have been cooler? No?
Total nonsense.
The great killing at the end of the Permian eliminated near 70% of all land vertebrates, but most notably over 90% of all marine species. Sediment studies from the late Permian through early Triassic show the oceans became acidic and anoxic resulting in the extinction of all the trilobites, fusulinids, blastoids, rugose and tabulate corals, and over 90% of the crinoids, ammonoids, and anthozoans.
Calcium sulfate gypsum beds of the late Permian are the best example of an acidic ocean, not to mention the anoxic cherts and carbonaceous claystones. And we’re to believe this all occurred in hot water.
According to the map the samples were taken from the “ancient conodonts (tiny teeth of extinct eel-like fishes)” which lived in the “dead zone”. They also say:
My sincere apologies if I missed something.
Just an engineer says:
Hate to have to point out the bleeding obvious, but there aren’t a lot of species living in Death Valley either!
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I hate to point out the obvious to you, but there are lots of species living in Death Valley–probably lower populations–but many lifeforms none the less:
Death Valley is home to more than 1000 species of plants
http://www.nps.gov/deva/naturescience/animals.htm
Wildlife and other animals in Death Valley National Park. … mammals, 36 reptiles , 5 amphibians, 6 fish, and nearly 400 bird species
http://digital-desert.com/death-valley/wildlife/
Some Pupfish species in the Death Valley area actually live in hot springs. The Pupfish of Salt Creek are so adapted to warm water
http://www.desertusa.com/mag98/june/stories/dvheat.html
Other wild animals in Death Valley include deer, mountain lion, bobcat, coyote …
http://www.ohranger.com/death-valley/flora-fauna
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Leo Morgan says:
The essence of skepticism is to not be too ready to believe a claim, while not being so intellectually dishonest as to deny evidence.
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Leo, I like your questions–makes me think, thanks
Also thanks to JJ–that was funny about the dead zones and “recovery.”
This paper stinks. It’s tantamount to putting ONE thermometer in south China and then using it to tell us what the global mean temperature is. And from fish that aren’t really there.
A massive release of methane due to the elevated temps has also been blamed for the Permian extinction. Link follows:
http://www.sciencedaily.com/releases/2003/08/030828071722.htm
VolcanoCafe had a discussion of the Icelandic hot spot and linked it to the one that caused the Siberian Traps. They go farther and suggest that it is putting out about the same volume per year as the Siberian Traps. Reason is that there are indications that the Siberian Traps took much longer to erupt than first thought. Link follows:
http://volcanocafe.wordpress.com/2012/07/16/the-icelandic-hotspot-hypervolcano-why-old-traps-wont-erupt-again/
Final thought: If the equatorial regions were much hotter, would that not also increase evaporation, cloud formation, and cloud coverage in the tropics and temperate regions? Cheers –
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.
There is no “global carbon cycling” – it has been dropping like a stone for the last 600 million years. We are now dangerously close (in geological terms) to the end of all life as we know it. CO2 (water and energy from the Sun) being the current base of the food chain.
So will the ‘Gravy Train’ now be heading for the Tropics to study ‘Tropical Collapse’?, nicer there than the Arctic.
Does this count as part of the sea?
Is it just possible that the studies sample came from China’s very own “Persian Gulf” of its day?
I guess they couldn’t think of any way for water in a shallow equatorial sea to be any more enriched in 018 than the open ocean.