NEW YORK, Oct. 25 (UPI) -- The Greenland ice sheet may keep melting because of a "self-amplifying" process even if temperatures don't hit record highs, a U.S. researcher says.
Marco Tedesco at The City College of New York said glaciers could undergo a self-amplifying cycle of melting and warming that would be difficult to halt.
"We are finding that even if you don't have record-breaking highs, as long as warm temperatures persist you can get record-breaking melting because of positive feedback mechanisms," Tedesco, who heads the school's Cryospheric Processes Laboratory, said in a CCNY release Tuesday.
Ice revealed as snow melts is darker and absorbs more heat than the overlying snow, he said, increasing the speed of melting in a runaway process.
A year that follows one with record high temperatures can have more dark ice just below the surface, ready to warm and melt as soon as temperatures begin to rise, Tedesco said, explaining why ice sheet melting can occur even though temperatures don't break records.
Only new falling snow can put on the brakes and halt the process by covering the darker ice in a reflective blanket, Tedesco said.
Studies show this year's snowfall couldn't compensate for melting in previous years. "The process never slowed down as much as it had in the past," he said. "The brakes engaged only every now and again."
