Changing Arctic Winds Threaten to Raise Global Sea Levels

Changing Arctic winds may be contributing to rising global sea levels, according to a new study.

Researchers from Australian National University and the University of New South Wales originally linked these fluctuating winds to southern Australia's drying climate, but now it appears that they are also warming ocean temperatures along the East and West Antarctic coasts.

"When we included projected Antarctic wind shifts in a detailed global ocean model, we found water up to 4 degrees Celsius [39 degrees Fahrenheit] warmer than current temperatures rose up to meet the base of the Antarctic ice shelves," lead author Dr. Paul Spence said in a statement.

"The sub-surface warming revealed in this research is on average twice as large as previously estimated with almost all of coastal Antarctica affected. This relatively warm water provides a huge reservoir of melt potential right near the grounding lines of ice shelves around Antarctica. It could lead to a massive increase in the rate of ice sheet melt, with direct consequences for global sea level rise."

Prior studies focused on rising sea levels and the rate of ice shelf melting due to the general warming of the ocean over large areas. This time, researchers examined in great detail the impact of changing winds on currents down to 700 meters around the coastline.

With the help of supercomputers at Australia's National Computational Infrastructure (NCI) Facility, they found that changes in the Antarctic coastal winds from climate change could be linked more closely to melting of the ice shelves, compared to broader warming of the ocean.

"It is very plausible that the mechanism revealed by this research will push parts of the West Antarctic Ice Sheet beyond a point of no return," explained Dr. Axel Timmerman, a professor of Oceanography at University of Hawaii.

Additionally, this research may help to explain a number of sudden and unexplained increases in global sea levels that have happened in the past.

"This work suggests the Antarctic ice sheets may be less stable to future climate change than previously assumed," Timmerman concluded.

The findings were published in the journal Geophysical Research Letters.