Will 2016 See Record Low Arctic Ice?
April 21, 2016
The passing of the winter peak signals the start of the melt season, where sea ice diminishes as temperatures rise through spring and into summer. Sea ice hits its lowest extent sometime in September or October. The record low for the summer minimum currently stands at 3.41m square kilometres, from 2012.
Speaking to Carbon Brief at EGU, Dr Marcel Nicolaus, a sea ice physicist at the Alfred Wegener Institute for Polar and Marine Research, says the 2016 summer could equal, or surpass, this record.
Sea ice conditions over the recent months are similar to those seen before the 2012 record, Nicolaus says. He identifies three main reasons why this year’s summer minimum could rival 2012:“We did see a stronger melt last summer than usual, so we went into the winter in November with thinner ice than the previous years. We saw, due to the warming, less freezing and less build-up of ice mass [during winter]. And we do see a shift of secure ice towards the northern end of the Fram Strait of the Atlantic Ocean, where it’s very likely to be exported [away from the Arctic and into the North Atlantic] over the course of spring and summer.”
These reasons won’t guarantee a new record, Nicolaus adds, because sea ice melt also depends on the warmth and storminess of spring and summer – but they do boost the odds.
Warmer than normal
With almost 13,000 scientists at the EGU conference this week, Carbon Brief caught up with a few of them to ask about the prospects for Arctic sea ice for this year and beyond.
Prof Julienne Stroeve, professor of polar observation and modelling at University College London and senior research scientist at the National Snow and Ice Data Centre (NSIDC), points out that a small winter sea ice extent doesn’t necessarily translate into a summer low.
She tells Carbon Brief:“Just because we have thinner ice and less sea ice right now – starting out the melt season – that doesn’t necessarily mean we’re going to have a new record low.”
That’s because the extent to how much sea ice melts through the summer is also dependent on the weather, Stroeve says. Thinner ice is more susceptible to being broken up by storms, which means it can melt more quickly. But scientists can’t predict the weather several months in advance, so there’s still a lot of uncertainties about how sea ice will fare over the summer.
Video below shows how a late summer storm in 2012 helped break up thin ice and set the stage for a low record.
That said, Stroeve also thinks the conditions are ripe for a new record:“We had a warm winter and the warmth has continued into spring. If you look at air temperatures for the first three weeks of April, for example, the temperatures are 4-5C warmer than normal over the whole Arctic Ocean…How that continues is going to play a key role, but certainly having thinner ice to start out with is not a good thing.”“This winter, we’ve seen very warm conditions in the Arctic. The air temperature has been very warm, which means the ice has not grown as much as it does normally, which means we’re left now at the start of the summer [melt] season with much less less ice than we do normally.“Whether this means we get a record low year later on in September when the ice reaches its minimum depends quite a lot on what the atmosphere does of the next few months – how many storms we get across the Arctic as they will help break up the ice. So, it depends on how many of those we get as to whether this year will be a record or not.”