Mar 7, 2013
The Earth is warmer now than during 70 to 80 percent of the time stretching back to the last Ice Age, according to researchers from Oregon State and Harvard universities who studied data from more than 73 global sites.
The findings also show that temperature-change rates are accelerating, Shaun Marcott, a scientist at Oregon State in Corvallis and one of the paper’s authors, said yesterday in an interview. The study was published today by the journal Science.
The research is the longest global reconstruction of temperature records over the last 11,300 years and mirrors results covering the past 2,000 years. The study may provide additional context in refuting “arguments that what we’re experiencing today is part of some natural climate variability,” Marcott said.
Marcott and his co-authors sifted through stacks of research including tree-ring records and fossils from thousands of years ago, and analyzed temperature records compiled by other scientists. From 8,000 years ago to 200 years ago the Earth experienced a wide range of temperatures, they said.
“From 1900 to 2000, we go from the cold end of that spectrum to the warm end of that spectrum -- the rates of change we’re seeing are unprecedented,” Marcott said. “We should still be cooling, but we’re not.”
According to climate models evaluated by the Intergovernmental Panel on Climate Change, temperatures will exceed the warmest of the past 11,300 years in 2100, the researchers said. The study was funded by the National Science Foundation’s Paleoclimate Program.