A new study based on four years of collecting ice core data says human activity and the El Nino weather pattern over the last century have warmed West Antarctica, part of the world's coldest continent. Major El Nino event from 1939 to 1942 and greenhouse emissions from cars and factories responsible for the West Antarctic warmeing. The study is carried out by scientists David Schneider and Eric J. Steig of the National Center for Atmospheric Research and published in the journal Proceedings of the National Academy of Sciences, August 12, 2008 doi:10.1073/pnas.0803627105.