While the Arctic sea ice has been decreasing over the years, the Antarctic sea ice extent has been increasing slightly — a phenomenon that has left scientists baffled.
“We wanted to understand this apparent paradox so that we can better understand what might happen to the Antarctic sea ice in the coming century with increased greenhouse warming,” said Jiping Liu, a research scientist in Georgia Tech's School of Earth and Atmospheric Sciences.
Warming climate accelerates the hydrological cycle, increasing snow precipitation, which covers the upper ocean and insulates it from the ocean heat below.
However, climate models predict greenhouse gases will continue to increase in the 21st century, which will result in the sea ice melting at a faster rate from both above and below.
Climate change is expected to heat the upper ocean, which will increase the melting of the sea ice from below. In addition, increased warming will also result in a reduced level of snowfall, but more rain.
Because rain doesn't reflect heat back the way snow does, this will enhance the melting of the Antarctic sea ice from above. “We may see, on a time scale of decades, a switch in the Antarctic, where the sea ice extent begins to decrease,” said Judith A. Curry.