November 1, 2013
Atmospheric Cooling Could Be Result Of Oceanic Heat Absorption
redOrbit Staff & Wire Reports - Your Universe Online
The apparent stabilization of atmospheric temperatures over the past decade -- often cited by climate change skeptics as evidence that global warming has slowed down or stopped -- is actually caused by a radical increase in the amount of heat being absorbed by the oceans, according to a new study.
Yair Rosenthal, a climate scientist at Rutgers University, and colleagues report that the ocean is now absorbing heat 15 times faster than it had over the previous 10,000 years. While that phenomenon could provide experts and government officials with additional time to deal with the climate change issue, it is a problem as well and will eventually have to be addressed.
“We may have underestimated the efficiency of the oceans as a storehouse for heat and energy,” Rosenthal, a professor of marine and coastal sciences in the Rutgers' School of Environmental and Biological Sciences, said in a statement Thursday. “It may buy us some time – how much time, I don't really know – to come to terms with climate change. But it's not going to stop climate change.”
Rosenthal and co-authors Braddock Linsley of Columbia University's Lamont-Doherty Earth Observatory and Delia W. Oppo of the Woods Hole Oceanographic Institution (WHOI), who have published their findings in the journal Science, created a reconstruction of Pacific Ocean temperatures during the past 10,000 years.
They discovered that the middle depths of the ocean have warmed 15 times faster over the past six decades than they did during the apparent natural warming cycles in the thousands of years prior.
“We're experimenting by putting all this heat in the ocean without quite knowing how it's going to come back out and affect climate,” said Linsley. “It's not so much the magnitude of the change, but the rate of change.”
In September, the UN’s Intergovernmental Panel on Climate Change (IPCC) released a report noting the recent slowdown in the rate of global warming, the researchers said. From the 1950s through much of the 1990s, worldwide temperatures increased approximately one-fifth of a degree Fahrenheit per decade. Following record highs in 1998, however, that warming rate was cut in half.
“The IPCC has attributed the pause to natural climate fluctuations caused by volcanic eruptions, changes in solar intensity, and the movement of heat through the ocean,” officials from Columbia University said in a statement. “The IPCC scientists agree that much of the heat that humans have put into the atmosphere since the 1970s through greenhouse gas emissions probably has been absorbed by the ocean.”
According to the study authors, the newly-published study puts that hypothesis into a long-term context, while suggesting that ocean waters may have been storing a greater percentage of human emissions than had been previously realized.
Based on the study’s long-term perspective, climate scientists believe that recent trends in global warming could just be random variations in which heat is transferred from the atmosphere to the ocean waters, and that the recent decrease could have little to no long-term impact on global climate change.