According to NASA and the National Snow and Ice Data Center (NSDIC), 2015 has the fourth lowest Arctic sea ice minimum since we’ve been recording such data. The Arctic sea ice minimum refers to the smallest land area that Arctic sea ice occupies in a given year. Sea ice, which is frozen seawater floating on top of the ocean, fluctuates through the year in response to temperatures, so there is less in the summer and more in the winter. That ice is very important, as it reflects a lot of the suns rays back into space, but as the ice melts, more rays get through, which makes global water temperatures higher.

arctic sea

This year, the minimum was down to 1.70 million square miles, which may sound like a lot, but that’s actually 699,000 square miles lower than the 1981-2010 average. In fact, the ten lowest minimum sea ice numbers have happened in the last 11 year.

It’s thanks, of course, to global climate change, which has been affecting Arctic sea ice since the 1970s. There are fluctuations each year, largely do to meteorological events, although there haven’t been many in the last few years that account for the numbers we’re seeing on their own.

But, as water temperatures rise, for a number of reasons, that water makes it harder for the ice to remain, and helps it melt. As the Arctic sea ice melts, it allows for more sunlight to hit water, which in turn raises water temperatures, and makes the sea ice melt faster. Arctic sea ice is still pretty resilient to melting, but less than it used to be. It doesn’t take as much to melt the ice anymore because the average temperature of the world’s ocean water has been rising.

As 2015 continues and the seasons shift, we’ll begin looking at data from the Antarctic to determine it’s minimum sea ice levels for this year.