While a steady and dramatic decline in the sea ice cover of the Arctic Ocean has been observed during the last three decades, something more complex is happening around Antarctica where the total extent of sea ice surrounding the continent in the Southern Ocean has grown by roughly 6,600 square miles every year during the same period, NASA scientists said.
"There's been an overall increase in the sea ice cover in the antarctic, which is the opposite of what is happening in the arctic," lead author Claire Parkinson, a NASA climate scientist, said.
This year's winter antarctic sea ice maximum extent, reached two weeks after the Arctic Ocean's ice cap experienced an all-time summertime low, was a record high for the satellite era of 7.49 million square miles, about 193,000 square miles more than its average maximum extent for the last three decades, researchers said.
However, the fact that some areas of the Southern Ocean are apparently cooling and producing more sea ice does not disprove a warming climate, Parkinson said.
"Climate does not change uniformly: The Earth is very large and the expectation definitely would be that there would be different changes in different regions of the world," she said. "That's true even if overall the system is warming."