Antarctic icebergs reduce effects of global warming in Southern Hemisphere

Aug. 13 (UPI) — Antarctic icebergs can temper or delay the impacts of global warming in the Southern Hemisphere, according to a new study.

The big picture is simple: as the concentration of greenhouse gases in the atmosphere grows, the planet gets warmer. Reality is more complicated. Hundreds of feedback mechanisms and thousands of variables can influence how quickly the planet warms.

Earth’s poles are home to many feedback mechanisms. As global warming has spurred rising ocean temperatures, several of Antarctica’s largest coastal glaciers have been rapidly thinning.

Most studies have focused on modeling the instability of Antarctica’s ice shelves and glaciers, with hopes of offering more accurate sea level rise predictions. For the latest study, scientists wanted to understand how Antarctica’s melting ice — and more specifically, its calving icebergs — influence the effects of climate change.

Scientists ran models designed to simulate the changing climate of a warming Southern Hemisphere. Researchers made sure the model accounted for the climatic effects of cool freshwater inputs — the effects of calving icebergs melting into the oceans. Previous studies suggest Antarctic calving rates are likely to increase in the decades ahead.

Researchers ran dozens of simulations, some with the iceberg effect turned on and others with it turned off. The results, published this week in the journal Nature Climate Change, showed an influx of icebergs has a cooling effect, reducing or delaying the effects of global warming on the Southern Hemisphere.

“Our results demonstrate that the effect of Antarctic melting and icebergs needs to be included in computer model simulations of future climate change,” lead study author Fabian Schloesser, climate scientists at the University of Hawaii at Manoa, said in a news release. “Climate models currently used in the 6th climate change assessment of the Intergovernmental Panel on Climate Change do not account for this process.”

Previous studies have suggested that accelerated iceberg calving would result in significant sea level rise, but the latest findings suggest the future of warming and melting in the Southern Hemisphere is more complicated. The new study suggests melting icebergs could, at least temporarily, slow the feedback loop of Antarctic warming and melting.

“Our research highlights the role of icebergs in global climate change and sea level rise,” said co-author Axel Timmermann, director of the Institute for Basic Science’s Center for Climate Physics. “Depending on how quickly the West Antarctic ice sheet disintegrates, the iceberg effect can delay future warming in cities such as Buenos Aires and Cape Town by 10 to 50 years.”





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