Atlantic Ocean circulation linked to rapid past climate change

Researchers at the University of Bristol have analyzed the chemistry of ocean sediments to investigate whether rapid climate change was linked to Atlantic Ocean circulation in the past. The study is providing new insight into the interactions between climate change, melting ice, and ocean circulation.

“Large, rapid changes in climate, carbon dioxide, and ice sheet volume occurred as the planet emerged from the most recent ice age some 20,000 years ago,” said study lead author Dr. Hong Chin Ng.

“Changes in the circulation of the Atlantic Ocean are believed to have played an important role in driving these climate events – but direct evidence has been hard to find.”

“In this study, we analyzed radioactive elements in ocean sediments to provide a much better-constrained picture of the strength of ocean circulation in the past, and therefore its relationship with the timing of ice sheet and climate changes during the last major deglaciation.”

The investigation was focused on sediment cores from across the Atlantic Ocean. The study revealed that shifts in ocean circulation patterns had corresponded with rapid climate change events when the ice sheets were retreating.

“This is the first time that spatially coherent, widespread observations (from the tropics to high latitudes) have been brought to together on a common age scale,” said Dr. Ng.

“We found that the ocean slowed down its circulation in two steps, linked to two episodes of ice melting – one from Eurasia and one from North America.”

The study findings highlight the influence of melting ice on the slowdown of ocean circulation. According to the researchers,  this is important because ice in the northern latitudes is currently melting at an accelerated rate due to climate change.

The data obtained from this research could be used to investigate whether climate models accurately respond to the dynamics of melting ice and ocean circulation during periods of rapid climate change.

The study is published in the journal Nature Communications.

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By Chrissy Sexton, Earth.com Staff Writer

Image Credit: Dr Hong Chin Ng, University of Bristol