Washington: A drop in carbon dioxide (CO2) levels seems to have triggered Antarctic ice sheet formation.
Scientists from Yale and Purdue Universities stumbled on the discovery
while examining molecules from ancient algae found in deep-sea core
Matthew Huber, professor of earth and atmospheric sciences at Purdue,
said roughly a 40 percent decrease in CO2 occurred prior to and during
the rapid formation of a mile-thick ice sheet over the Antarctic
approximately 34 million years ago.
"We went from a warm world without ice to a cooler world with an ice
sheet overnight, in geologic terms, because of fluctuations in carbon
dioxide levels," he added, the Science journal reported.
For 100 million years prior to the cooling, which occurred at the end of
the Eocene epoch, earth was warm and wet. Mammals and even reptiles and
amphibians inhabited the North and South poles, which then had
Then, over a span of about 100,000 years, temperatures fell
dramatically, many species of animals became extinct, ice covered
Antarctica and sea levels fell as the Oligocene epoch began, according
to a Yale and Purdue statement.
Mark Pagani, the Yale geochemist who led the study, said polar ice
sheets and sea ice exert a strong control on modern climate, influencing
the global circulation of warm and cold air masses, precipitation
patterns and wind strengths, and regulating global and regional
"The onset of Antarctic ice is the mother of all climate 'tipping
points,'" he said. "Recognising the primary role carbon dioxide change
played in altering global climate is a fundamentally important