ClimatePast experience shows that Earth can recover from global warming
When faced with high levels of atmospheric carbon dioxide and rising temperatures fifty-six million years ago, the Earth increased its ability to pull carbon from the air;this led to a recovery that was quicker than anticipated by many models of the carbon cycle — though still on the order of tens of thousands of years, a new study finds; researchers found that more than half of the added carbon dioxide was pulled from the atmosphere within 30,000 to 40,000 years, which is one-third of the time span previously thought
Tools of rapid atmospheric carbon reduction // Source: ecocho.in
As the debate continues about whether or not we are witnessing a warming of the atmosphere, and, if we do, to what extent human activity contributes to it, we note the findings of a new research: the Earth may be able to recover from rising carbon dioxide emissions faster than previously thought, according to evidence from a prehistoric event analyzed by a Purdue University-led team.
When faced with high levels of atmospheric carbon dioxide and rising temperatures fifty-six million years ago, the Earth increased its ability to pull carbon from the air. This led to a recovery that was quicker than anticipated by many models of the carbon cycle — though still on the order of tens of thousands of years, said Gabriel Bowen, the associate professor of earth and atmospheric sciences who led the study.
“We found that more than half of the added carbon dioxide was pulled from the atmosphere within 30,000 to 40,000 years, which is one-third of the time span previously thought,” said Bowen, who also is a member of the Purdue Climate Change Research Center. “We still don’t know exactly where this carbon went, but the evidence suggests it was a much more dynamic response than traditional models represent.”
A Purdue University release reports that Bowen worked with James Zachos, a professor of earth and planetary sciences at the University of California, Santa Cruz, to study the end of the Palaeocene-Eocene Thermal Maximum, an approximately 170,000-year-long period of global warming that has many features in common with the world’s current situation, he said.
“During this prehistoric event billions of tons of carbon was released into the ocean, atmosphere and biosphere, causing warming of about 5 degrees Celsius,” Bowen said. “This is a good analog for the carbon being released from fossil fuels today.”
Scientists have known of this prehistoric event for twenty years, but how the system recovered and returned to normal atmospheric levels has remained a mystery.
Bowen and Zachos examined samples of marine and terrestrial sediments deposited throughout the event. The team measured the levels of two different types of carbon atoms, the isotopes carbon-12 and carbon-13. The ratio of these isotopes changes as carbon dioxide is drawn from or added to the atmosphere during the growth or decay of organic matter.
Plants prefer carbon-12 during photosynthesis, and when they accelerate their uptake of carbon dioxide it shifts the carbon isotope ratio in the atmosphere. This shift is then
