Cataclysmic volcanic eruptions in Greenland and the British Isles brought on a destructive bout of global warming 55 million years ago, an international study revealed Thursday.
The eruptions also separated Greenland from Europe by giving birth to the North Atlantic Ocean, said the study in the April 26 issue of Science.
The findings are important 55 million years after the fact, because the volcanic activity released large amounts of methane and carbon dioxide and warmer temperatures followed -- just as scientists warn is happening today.
And the release of these so-called greenhouse gases had the effect scientists today fear, of raising surface water temperatures five degrees C (nine degrees F) in the tropics and more than six degrees (11 degrees F) in the Arctic, said the study of marine fossils and geology of the period.
"There has been evidence in the marine record of this period of global warming and evidence in the geological record of the eruptions at roughly the same time but until now there has been no direct link between the two," said Robert Duncan, professor at Oregon State University and an author of the study.
Deep-water ocean life was snuffed out by large amounts of plankton near the surface, blocking light and oxygen filtering down to the level of fish, which became extinct, they said.
Since the Industrial Revolution, scientists say, humans have been releasing ever greater amounts of carbon and methane into the atmosphere, exaggerating the greenhouse effect, which allows light to enter Earth's atmosphere but does not allow the heat to escape, much as the glass in a greenhouse.
Scientists look at rising Earth temperatures, melting polar ice and changing weather patterns as evidence of global climate change.