A University of Oklahoma-led study recently found that explosive volcanic eruptions were at least 3-8 times more frequent during the peak of the Late Paleozoic Ice Age (~360 to 260 million years ago). Aerosols produced by explosive volcanism helped keep large ice sheets stable, even when CO2 levels increased, by blocking sunlight. But the volcanic emissions also may have started a cascade of effects on the climate system that resulted in additional CO2 removal from the atmosphere.