Science Daily reports on an online article published in the Oct 8 Science that CO2 levels haven’t been this high in 15 million years. Yale Environment 360 picks up the thread. This recent finding was unearthed by examining ancient marine algae, not tree rings. (Yes, I know. The tree ring data were used to reconstruct temperatures, not CO2 levels.)
“The last time carbon dioxide levels were apparently as high as they are today — and were sustained at those levels — global temperatures were 5 to 10 degrees Fahrenheit higher than they are today, the sea level was approximately 75 to 120 feet higher than today, there was no permanent sea ice cap in the Arctic and very little ice on Antarctica and Greenland,” said the paper’s lead author, Aradhna Tripati, a UCLA assistant professor in the department of Earth and space sciences and the department of atmospheric and oceanic sciences.
“Carbon dioxide is a potent greenhouse gas, and geological observations that we now have for the last 20 million years lend strong support to the idea that carbon dioxide is an important agent for driving climate change throughout Earth’s history,” she said.
387 ppm. That’s quite a milestone.