Warmer ocean temperatures, combined with unseasonal wind patterns have contributed to a record drop in Antarctic sea ice levels, an international research report has found.
Researchers from Monash University, the Bureau of Metrology and a number of American universities have found that natural variabilities in natural systems in the Antarctic have contributed to dramatic and sustained melting of the ice sheets, but human-induced climate change may also be a contributing factor.
Associate Professor Julie Arblaster from Monash University’s School of Earth, Atmosphere and Environment said: “Such large and rapid changes rarely occur in the natural system. This led our research teams to ask the question of what caused the initial sea ice decline and what changes in the climate system are sustaining it?”
The studies identified that highly unusual conditions in tropical oceans and the Antarctic stratosphere triggered wind patterns across the bottom part of the globe which led to the initial sea ice declines.
“In the winter and spring of 2016, sea surface temperatures and rainfall in the tropical Indian Ocean and western Pacific were well above their normal values. We found that these tropical events generated wind patterns near Antarctica that almost perfectly matched the main regions where sea ice initially declined,” Dr Guomin Wang from the Australian Bureau of Meteorology said.
The climate system not only has natural variability on year-to-year timescales, but also from decade-to-decade. Warmer subsurface waters near Antarctica have been slowly moving upwards towards the surface by patterns induced by the tropical Pacific over the past 10-15 years.