Saturday August 12, 2017

Massive ice sheets weirdly warmed us up

Weathering of Earth by glaciers may have warmed Earth over eons by aiding the release of carbon dioxide into the atmosphere. A new study shows the cumulative effect may have created negative feedback that prevented runaway glaciation.

Weathering of Earth by glaciers may have warmed Earth over eons by aiding the release of carbon dioxide into the atmosphere. A new study shows the cumulative effect may have created negative feedback that prevented runaway glaciation. (Paul Quackenbush)

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Under ordinary circumstances the Earth cycles between ice ages and warm periods about every hundred thousand years. We're currently in one of the warm periods now.  

Mark Torres

Dr. Mark Torres (Courtesy Mark Torres)

A new study, lead by Mark Torres, makes the surprising suggestion that the glaciers that grow during cold periods actually tend to drive warming.

During ice ages, glaciers wear down and dissolve rock.  This speeds up chemical reactions with the dissoved minerals in the rock that release carbon stored in rocks and in the ocean into the the atmosphere in the form of carbon dioxide. That CO2 then leads to warming.

Then as the glaciers melt, the carbon release stops, and the climate cools again and a new ice age begins.  

Glacer image

(Ben Shannon)

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