Ice age temperatures and greenhouse gases

Ice age temperatures and greenhouse gases

. Ice core data indicate that changes in the atmospheric temperature over Antarctica closely parallel variations in the atmospheric concentrations of two greenhouse gases, carbon dioxide and methane, for the past 160,000 years. When the temperature rises, so does the amount of these two greenhouse gases, and vice versa. This strong correlation has been extended by a deeper Vostok ice core, to 3,623 meters in depth and the past 420,000 years. The carbon dioxide and methane increases could amplify orbital forcing of climate change. The ice core data does not include the past 200 years, shown as a dashed lines at the right. They show that the present-day levels of carbon dioxide and methane are unprecedented during the past four 100,000-year glacial-interglacial cycles.

Copyright 2010, Professor Kenneth R. Lang, Tufts University