By Louise Gray, Environment Correspondent
A conference organised by the Geological Society in London this week will bring together scientists from around the world to look at how the world coped with climate change in the past. By studying rock sediments from millions of years ago geologists have been able to model how increases in greenhouse gases led to temperature change and extinction of species.
Professor Jim Zachos, of the University of California, said that 55 million years ago volcanic activity caused around 4,500 gigatons of greenhouse gases to be released into the atmosphere over thousands of years. This caused the planet to warm by 6C (10.8F), forcing whole ecosystems, including early mammals, to adapt, migrate or die out in certain areas. Prof Zachos said that if the world continues to pump out greenhouse gases at the current rate, around 5,000 gigatons of greenhouse gases will be released into the atmosphere over a few hundred years.
He said this will cause a more rapid temperature rise that at any other time in history and could cause “mass extinction of species”. “The impacts will be pretty severe compared to 55 million years ago in terms of evolution of this planet,” he said. The Geological Society warned that it could take the Earth 100,000 years to recover.
A statement read: “The geological evidence from the 55 million year event and from earlier warming episodes suggests that such an addition [a massive increase in greenhouse gases caused by the activities of mankind] is likely to raise average global temperatures by at least 5 to 6C, and possibly more, and that recovery of the Earth’s climate in the absence of mitigation measures could take 100,000 years or more. Numerical models of the climate system support such an interpretation. In the light of the evidence presented here it is reasonable to conclude that emitting further large amounts of carbon dioxide into the atmosphere over time is likely to be unwise, uncomfortable though that fact may be.”