Narrator: This is Science Today. Variations in Antarctic sea ice may have played a vital role in the puzzling low levels of atmospheric carbon dioxide present during the last ice age. Ralph Keeling, a researcher at the University of California, San Diego's Scripps Institution of Oceanography, used a computer model to gain insight into past climate changes.
Keeling: What we worked on was an idea that by covering the region where the deep waters upwell with sea ice, which plausibly might have happened in a colder climate like the ice ages, you could significantly reduce the amount of carbon dioxide in the atmosphere. The gases don't go through a solid very efficiently.
Narrator: Atmospheric carbon dioxide levels depend on how efficiently carbon dioxide-rich water from the deep ocean returns to the surface. Recently, it was discovered that these deep waters primarily return to the surface around Antarctica.
Keeling: People of course are well aware that carbon dioxide has a potential for changing climate, but it's clear from the Ice Age records that the carbon dioxide concentration itself was influenced by climate. So, we have potential for positive feedbacks.
Narrator: For Science Today, I'm Larissa Branin.