London, March 9 (ANI): A team of scientists has claimed to have solved the mystery about the so-called high level of carbon dioxide (CO2) present in the atmosphere during the big ice age 444 million years ago.
The Ordovician ice age happened 444 million years ago, and records have suggested that CO2 levels were relatively high then.
But, the puzzle is that if the CO2 levels were so high, then how did the ice age happen in the first place.
According to a report in New Scientist, research by Seth Young of Indiana University in Bloomington, has suggested that CO2 levels during the ice age were not that high after all.
As part of the research, Young did a detailed analysis of carbon-13 levels in rocks formed at the time.
The picture that emerged was very different.
Young found CO2 concentrations were in fact relatively low when the ice age began.
Lee Kump of Pennsylvania State University in University Park said that earlier studies missed the dip because they calculated levels at 10-million-year intervals and the ice age lasted only half a million years.
The dip, according to him, was triggered by a burst of volcanic activity that deposited new silicate rocks.
These draw CO2 out of the air as they erode.
As the ice spread, however, it gradually covered the silicate rocks, slowing the erosion and so allowing CO2 to build up in the atmosphere once more.
"This eventually would have warmed the atmosphere enough to end the ice age," said Kump. (ANI)