Researchers from the National Center for Atmospheric Research and the University of Washington used ice cores to link dramatic year-to-year temperature swings and a century-long warming trend across West Antarctica with global warming and periodic events such as El Nino.
"As the tropics warm, so too will West Antarctica," said NCAR's David Schneider, who led the research with University of Washington Associate Professor Eric Steig. "These ice cores reveal West Antarctica's climate is influenced by atmospheric and oceanic changes thousands of miles to the north."
The scientists said although most El Nino warming occurs in the tropical Pacific, it often fosters a circulation pattern that pushes relatively mild, moist air toward West Antarctica, displacing much colder air. As a result, West Antarctica has one of the world's most variable climates.
Steig said although the influence of tropical climate on West Antarctica climate wasn't unknown, "these results are the first to demonstrate that we can unambiguously detect that influence in ice core records."
The research appears in the early online edition of the Proceedings of the National Academy of Sciences.