The Great Warming Extinction was Even More Deadly Than Believed
October 19, 2012
Life about 250 million years ago was hard to come by. In fact, it was nearly non-existent. Scientists, studying why this period, known as the end-Permian event, lasted so long and have found a key ingredient: heat.
Paul Wignall, a paleontologist at England’s Leeds University, and study coauthor, said during the 200,000-year-long Permian extinction the Earth began cooking, with life struggling to thrive, especially at the equator.
The end-Permian event was also met with a large die-off of plants. And with no plants around to consume carbon dioxide (a gas that warms the planet) the earth became “like a runaway greenhouse—it [started] to get out of control,” said Wignall.
While some life survived the Permian extinction–such as snails and clams–the intense heat soon even killed these creatures, leaving the planet a virtual “dead zone” for 5 million years, he said. While dead zones are typically seen after extinction events, they usually only last on a scale of tens of thousands of years. So it was perplexing to find the dead zone from the Permian extinction event lasted on a scale of millions, rather than thousands, of years.
Lead author Yadong Sun, along with Wignall and research partners from China University of Geosciences and University of Erlangen-Nurnburg in Germany, found that the lengthy die-off was due to a temperature rise in the tropics to around 104°F at sea-surface and up to 140°F on land.
“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,” said Sun, who holds a PhD in geology at Leeds.
This was also the first study to show water temperatures close to the ocean’s surface can reach temperatures of more than 100°F–a temperature at which point marine life cannot thrive and photosynthesis stops. Until now, climate models have only been able to show sea-surface temperatures reaching a maximum of 86°F.
Couple of things. As the story mentions, climate models have been unable to simulate the intensity of heat that the pale-evidence now indicates. So, when deniers say that climate models are imperfect, they are in some instances correct – but that fact should not give us comfort. This study, and contemporary observations such as changes in arctic ice, show that climate models in many instances have underestimated greenhouse impacts.
Another major kill factor was that, as the ocean warmed and stopped producing oxygen, certain types of organisms began to be favored, organisms that produced deadly hydrogen sulfide and poisoned the atmosphere in a truly deadly one-two punch.
The video below features Richard Alley discussing this and other issues.