Scientists at the National Snow and Ice Data Center (NSIDC) say that after reaching the summer minimum, the Arctic sea ice will generally start to grow from late September through late February or early March, then start melting again from March through September.
The minimum and maximum extents don’t necessarily coincide with the peaks of summer and winter because the ocean takes longer to warm up and cool down. The record low for the summer minimum was set in 2012 when sea ice extent fell to 3.39 million square kilometers (1.31 million square miles).
Scientists began recording the yearly cycle of sea-ice extent beginning in 1976, the first year we had continuous satellite coverage data on global sea ice cover. Interestingly, all of the lowest summer extents in the satellite record occurred in the last 10 years.
The NSIDC does note that this year’s minimum is preliminary because “changing winds or late season melt could still reduce the Arctic ice extent.”
On March 29, Digital Journal reported the Arctic sea ice began the 2016 melt season with a record low maximum extent of 14.52 million square kilometers (5.607 million square miles). It was also pointed out that the Arctic has been warming about twice as fast as the rest of the world. The Arctic has warmed about four degrees since climate change began.
The late season ice loss from Sept. 1 through Sept. 10 was greatest in an area that extends from the eastern Beaufort Sea to the northern Chukchi Sea. This region was impacted by two typhoons. The strong winds can compact the ice cover, leading to an upward mixing of warm ocean water.
Without a doubt, 2016 has been an interesting year in the Arctic, say NSIDC scientists. The season started with a record low maximum, and CryoSat satellite observations of the sea ice thickness showed the ice pack was around 5.0 centimeters thinner than usual well before the summer melting season.
Prof. Andrew Shepherd, professor of earth observation at the University of Leeds said, “So we could be heading for a record minimum in the total amount of ice, given that the extent has dropped so low. We won’t know for sure until next month because the ice pack tends to thin for a few more weeks before it starts to refreeze.”
