New Study Shows Three Abrupt Pulses of CO2 During Last Deglaciation

A new multi-institutional study including Scripps Institution of Oceanography, UC San Diego, shows that the rise of atmospheric carbon dioxide that contributed to the end of the last ice age more than 10,000 years ago did not occur gradually, but was characterized by three “pulses” in which CO2 rose abruptly.

Scientists are not sure what caused these abrupt increases, during which levels of carbon dioxide, a greenhouse gas, rose about 10-15 parts per million (ppm) – or about five percent per episode – over a period of one to two centuries. It likely was a combination of factors, they say, including ocean circulation, changing wind patterns, and terrestrial processes. Scripps geoscientist Jeff Severinghaus said the three episodes, which took place 16,100 years ago, 14,700 years ago, and 11,700 years ago are strongly linked to abrupt climate change events that took place in the Northern Hemisphere.

“We used to think that naturally occurring changes in carbon dioxide took place relatively slowly over the 10,000 years it took to move out of the last ice age,” said Shaun Marcott, lead author on the article who conducted his study as a postdoctoral researcher at Oregon State University. “This abrupt, centennial-scale variability of CO2 appears to be a fundamental part of the global carbon cycle.”