New study suggests that Earths climate has evolved to become more sensitive to greenhouse gases
By Summit Voice
SUMMIT COUNTY — The modern era’s link between atmospheric carbon dioxide levels and temperatures is nearly undisputed as both have climbed in tandem during recent decades.
But new studies of fossilized plankton suggests there was a time in the Earth’s history, about 12 million to 5 million years ago, when the climate warmed without a corresponding increase in atmospheric CO2, perhaps because of vastly different circulation patterns in the world’s oceans.
The scientists, led by Jonathan LaRiviere and Christina Ravelo of the University of California at Santa Cruz, reconstructed an open-ocean Pacific temperature record during the late Miocene epoch, finding that temperatures across a broad swath of the North Pacific were 9-14 degrees Fahrenheit warmer than today, while atmospheric carbon dioxide concentrations remained low–near values prior to the Industrial Revolution. (more…)