Volcanic eruption heated up the climate

Correlation between prehistoric eruption and increase in greenhouse gases and sea temperatures

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A massive volcanic eruption 55 million years ago not only pushed Greenland and Europe apart, but also changed the global climate. In the Science magazine, scientists report that the methane and carbon dioxide released during the eruption played a crucial role in this.

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Scientists from the Danish Roskilde University and the US universities of Oregon State, Rutgers and New Jersey have for the first time more accurately dated a layer of volcanic ash and lava underground in East Greenland and the Faro Islands from 55 million years ago, For this they measured the content of the noble gas argon contained in the volcanic minerals, whose concentration allows conclusions to be drawn on the time of formation of the minerals.

Correlation between volcanism and climate confirmed

The investigated lava forms in the North Atlantic region as a layered deposit of up to seven kilometers thick and is the relic of massive eruptions along the Mid-Atlantic Ridge. In a sense, it is the "seam" in the earth's crust that separates Europe and North America. With their new dating techniques, the researchers were able for the first time to precisely assign the ash and lava strata to the phase of sudden global warming.

"Scientists are aware of this great prehistoric warming phase, called the Paleocene-Eocene thermal maximum, for a long time, " explains Carl Swisher, professor of geology at Rutgers University. "Sea sediments show a sudden release of carbon dioxide accompanied by an increase in the acidity of the sea and the extinction of many deep-sea species. Now, for the first time, we geologists have a precise correlation and can correlate the sudden increase in volcanic activity with the increase in greenhouse gases. "Ad

Methane and CO2 heated up the climate

Apparently, the eruption on the Mid-Atlantic Ridge released so much methane and carbon dioxide that sea temperatures rose by five to six degrees Celsius in a short time. "The prehistoric volcanic activity has released more than 2, 000 gigatons of carbon in the form of methane and CO2 into the oceans and atmosphere, " said Michael Storey of Roskilde University. "This carbon was originally thought to be due to the decomposition of older underground organic deposits - similar to the layers we use today to extract oil or gas."

The new results not only improve the understanding of sudden climatic swings in the past, they also give researchers a deeper insight into the interactions between subsoil, sea and atmosphere - knowledge that could be crucial in the face of today's climate change.

(Rutgers, State University of New Jersey, April 27, 2007 - NPO)