While world is aware of a plethora of causes which receded the last Ice Age such as solar radiation, ocean currents and others, a new study has focused on mere carbon dioxide that it said had resulted mainly in eroding the glaciers.
The study based on measuring isotopes in boulders uncovered during the global meltdown 11,000 years ago, said the resultant rise of carbon dioxide, which was naturally occurring during those day, was the primary driving factor in the simultaneous global retreat of glaciers.
Glaciers, which are very sensitive to temperature, suddenly became sensitive and depleted in a global scale ending the Ice Age point out the need to have a broad, global reason for the world’s thermostat’s increasing rate, said Boston College researcher Jeremy Shakun. “The only factor that explains glaciers melting all around the world in unison during the end of the Ice Age is the rise in greenhouse gases,” he explained.
As is visible even today, he said, “In any given decade you can always find some areas where glaciers are holding steady or even advancing, but the big picture across the world and over the long run is clear – carbon dioxide is making the ice melt.”
Shakun and his team attribute it to the dramatic increase in manmade greenhouse gases behind the possible eradication of many of the world’s glaciers by the end of this century. “This has relevance to today since we’ve already raised CO2 by more than it increased at the end of the Ice Age, and we’re on track to go up much higher this century … which adds credence to the view that most of the world’s glaciers will be largely gone within the next few centuries, with negative consequences such as rising sea level and depleted water resources,” said Shakun.
The team reexamined samples taken from boulders that were left by the retreating glaciers, and even experts from Oregon State University, University of Wisconsin-Madison, Purdue University and the National Center for Atmospheric Research in Boulder, Colorado joined the research project.
Each boulder has been exposed to cosmic radiation after melting and the exposure has produced the isotope Beryllium-10 in the boulder, which was measured by scientists to determine when glaciers melted and the process called “surface exposure dating” for more than two decades helped the team to accurately determine the boulder ages.
The new exposure ages connected to the timing of the rise of carbon dioxide concentration in the atmosphere, a development recorded in air bubbles taken from ice cores pointed them to the inevitable glacial melting across the globe at the end of the Ice Age.
“Our study really removes any doubt as to the leading cause of the decline of the glaciers by 11,000 years ago – it was the rising levels of carbon dioxide in the Earth’s atmosphere,” said Shakun.
Carbon dioxide rose from 180 parts per million to 280 ppm at the end of the last Ice Age, which spanned nearly 7,000 years. But now, following more than a century of industrialization, carbon dioxide levels have risen to approximately 400 ppm, which far more than the fate of the last Ice Age that melted. If 400 ppm continues, it si sure to melt more glaciers, they warn.
“This tells us we are orchestrating something akin to the end of an Ice Age, but much faster. As the amount of carbon dioxide continues to increase, glaciers around the world will retreat,” said Shakun.
The report has been published in the journal Nature Communications.