The Shrinking Extent Of Arctic Sea Ice

If you haven’t been paying attention to the extent of Arctic Sea ice over the last decade, then it’s time to start. Satellite measurements began in earnest in 1979, and 2018’s Arctic Sea ice extent in October was about 2.34 million square miles. That might sound like a lot of ice, but it represents the third lowest extent in the nearly four decades that data has been recorded. The record low occurred in October 2012.

The trend isn’t expected to stop. Scientists expect we might see an Arctic free of ice cover by the year 2050. Jump forward to 2100, and we might see three months of an Arctic free of sea ice for a whopping five months, up from three.

The ice is important for a number of reasons, not least of which is that polar bears need it to survive. The ice is a key ingredient in temperature regulation around the world, and without it we could see temperatures skyrocket. We’re already experiencing out-of-whack weather patterns everywhere we look, but it’s nothing compared to we’ll see in the future.

Obviously, carbon dioxide is a big driver of this change because it helps trap heat to warm the surface of the planet. There are other factors that contribute, and they’re going to play more of a role in the coming decades. Heat is carried by the wind. Ocean currents during periods of increased temperatures throughout the Atlantic Ocean can lead to warmer water in the Arctic, transported along the Gulf Stream.

Another factor is atmospheric temperature. In tropical rainforests, there is a feedback pattern in which air rises to higher altitudes because of high temperature and excess moisture below. When the warmer air rises beyond a certain point, it escapes the atmosphere. This isn’t what happens in the Arctic. There, the air is trapped closer to the ground, contributing to more ice melt over time.

The overall minimum extent of sea ice in the Arctic has plummeted about 40 percent since those measurements first began in 1979. That means in order to be ice-free by 2050, the rate of sea ice melt has to occur faster. And it is.

If somehow the Paris Climate Agreement outlined goals are kept, then we might not see these ice-free summers. Unfortunately, that seems unlikely if not impossible.