Scientists have known for decades that small changes in climate can have significant impacts on the massive Antarctic Ice Sheet. Now a new study suggests the opposite also is true. An international team of researchers has concluded that the Antarctic Ice Sheet actually plays a major role in regional and global climate variability — a discovery that may also help explain why sea ice in the Southern Hemisphere has been increasing despite the warming of the rest of the Earth.
Results of the study are being published this week in the journal Nature….”What we discovered, however, is that the ice sheet has undergone numerous pulses of variability that have had a cascading effect on the entire climate system.”
….”The introduction of that cold, fresh water lessens the salinity and cools the surface temperatures, at the same time, stratifying the layers of water,” Clark said. “The cold, fresh water freezes more easily, creating additional sea ice despite warmer temperatures that are down hundreds of meters below the surface.” The discovery may help explain why sea ice has expanded in the Southern Ocean despite global warming, the researchers say
…The Antarctic Ice Sheet covers an area of more than 5 million square miles and is estimated to hold some 60 percent of all the fresh water on Earth. The east part of the ice sheet rests on a major land mass, but in West Antarctica, the ice sheet rests on bedrock that extends into the ocean at depths of more than 2,500 meters, or more than 8,000 feet, making it vulnerable to disintegration.
Scientists estimate that if the entire Antarctic Ice Sheet were to melt, global sea levels would rise some 200 feet…
Pepijn Bakker, Peter U. Clark, Nicholas R. Golledge, Andreas Schmittner, Michael E. Weber. Centennial-scale Holocene climate variations amplified by Antarctic Ice Sheet discharge. Nature, 2016; DOI: 10.1038/nature20582