The reports from studies of the extent of sea ice in the polar regions show opposite trends. The north Arctic region is losing areal coverage. The south Antarctic region is gaining areal coverage of sea ice. I discussed these two opposite trends in this recent post. The question many people have is whether this is a bad thing or not. Doesn’t the gain in the south cancel out the loss in the north so it comes out equal?
Claire Parkinson is in her fourth decade of studying polar sea ice. She often got that question from audiences after her presentations. She examined data from 1979 thru 2013 and charted the results below. It is clear the Arctic sea ice losses are profound in the first graph. Also clear is the trend of increases in the Antarctic sea ice in the second graph. That increase is not as large as the losses, however. The third graph shows the Combined data and the overall global decrease. More details of this story can be found at this link at NASA Earth Observatory.
Earth has been shedding sea ice at an average annual rate of 35,000 square kilometers (13,500 square miles) since 1979—the equivalent of losing an area of sea ice larger than the state of Maryland every year.
References and Related Reading
- Parkinson, C.L. (2014) Global Sea Ice Coverage from Satellite Data: Annual Cycle and 35-Yr Trends. Journal of Climate, 27, 9377–9382.
- NASA Earth Observatory (2014, September 24) A Tale of Two Poles.
- NASA Earth Observatory (2014) Antarctic Sea Ice.
- NASA Earth Observatory (2014) Arctic Sea Ice.
- NASA Earth Observatory (2009, April 20) Sea Ice.