The level of carbon dioxide in the atmosphere today is likely higher than it has been anytime in the past 3 million years. This rise in the level of carbon dioxide, a greenhouse gas, could bring temperatures not seen over that entire timespan, according to new research.
The study researchers used computer modeling to examine the changes in climate during the Quaternary period, which started around 2.59 million years ago and continues into today. Over that period, Earth has undergone a number of changes, but none so rapid as those seen today, said study author Matteo Willeit, a postdoctoral climate researcher at the Potsdam Institute for Climate Impact Research. [Photographic Proof of Climate Change: Time-Lapse Images of Retreating Glaciers]
“To get a climate warmer than the present, you basically have to go back to a different geological period,” Willeit told Live Science.
The Quaternary period began with a period of glaciation, when ice sheets stole down from Greenland to cover much of North America and northern Europe. At first, these glaciers advanced and retreated on a 41,000-year cycle, driven by changes in the Earth’s orbit around the sun, Willeit said.