Sea Ice Has Diminished Much Faster Than Climate Models Anticipated

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April 19, 2017

First-year sea ice floes, interspersed by open-water leads, brash ice and thin, snow-free nilas and young sea ice over the East Beaufort Sea. Photo via NASA

By Eric Roston and Blacki Migliozzi (Bloomberg) Eight countries control land in the Arctic Circle. Five have coastlines to defend. The temperature is rising. The ice is melting. The race for newly accessible resources is beginning. And Russia is gaining ground.

The story of the Arctic begins with temperature but it’s so much more—this is a tale about oil and economics, about humanity and science, about shipping, about politics and borders and the emerging risk of an emboldened and growing Russian empire.

Related Book: In the Kingdom of Ice - The Grand and Terrible Polar Voyage of the USS Jeannette by Hampton Sides
Related Book: In the Kingdom of Ice – The Grand and Terrible Polar Voyage of the USS Jeannette by Hampton Sides

The world as a whole has warmed about 0.9 degrees Celsius (1.7 degrees Fahrenheit) since 1880. Arctic temperatures have risen twice that amount during the same time period. The most recent year analyzed, October 2015 to September 2016, was 3.5C warmer than the early 1900s, according to the 2016 Arctic Report Card. Northern Canada, Svalbard, Norway and Russia’s Kara Sea reached an astounding 14C (25F) higher than normal last fall.

Scientists refer to these dramatic physical changes as “Arctic amplification,” or positive feedback loops. It’s a little bit like compound interest. A small change snowballs, and Arctic conditions become much less Arctic, much more quickly.

“After studying the Arctic and its climate for three-and-a-half decades,” Mark Serreze, director of the National Snow and Ice Data center, wrote recently. “I have concluded that what has happened over the last year goes beyond even the extreme.” 

The heat is making quick work of its natural prey: ice.

Scientists track the number of “freezing-degree days,” a running seasonal tally of the amount of time it’s been cold enough for water to freeze. The 2016-2017 winter season has seen a dramatic shortfall in coldness—more than 20 percent below the average, a record.

Sea ice has diminished much faster than scientists and climate models anticipated. Last month set a new low for March, out-melting 2015 by 23,000 square miles.

Compared with the 1981-2010 baseline, the average September sea-ice minimum has been dropping by more than 13 percent per decade. A recent study in Nature Climate Change estimated that from 30-50 percent of sea ice loss is due to climate variability, while the rest occurs because of human activity.

Receding ice decreases the Earth’s overall reflectivity, making the Arctic darker and therefore absorbing even more heat.

The ice is not all the same age or thickness, although it has become somewhat more uniform. In 1985, about 45 percent of Arctic sea ice was made up of older and thicker multi-year ice. By 2016, that number shrank to 22 percent.

With a greater percentage of seasonal ice, which disappears each Arctic summer, nations of the north have more time and opportunity to explore the resources beneath and within their territorial waters.

The sea-ice loss is President Vladimir Putin’s gain. Already the largest country on the planet, Russia stands to gain access to shipping routes and energy reserves, and a strategic military advantage from the opening of the Arctic.

Along the Russian coastline, which makes up more than half the Arctic total, winds and currents push old ice away from potential shipping lanes and prevent the build-up of thicker, multi-year ice that would leave other parts of the Arctic impassable for longer periods. That dynamic helps bring the Northern Sea Route—shippers’ hoped-for Russian express between Western Europe and East Asia—closer to fruition.

Sea ice, by definition, is already in the water and therefore doesn’t add to rising ocean levels as it dissolves. The same logic does not apply to Greenland’s melting glaciers and ice sheets. Last year, Greenland saw the second-largest melt on record. The hot season lasted a troubling 30 to 40 days longer than usual in the northeast portion of the region.

There’s enough water locked up in Greenland’s ice sheet to raise seas worldwide by 20 feet. While it may take centuries to fully melt, scientists are concerned that we have a limited time to act to prevent the climate from locking in the ice sheet’s demise.

Life in the Arctic is changing along with the climate. “Green ice” has appeared in recent years. Named for its distinctive hue, this ice is so thin that sunlight shines through, allowing phytoplankton to thrive. Vegetation growth in parts of Canadian and Russian Arctic waters has boomed to from 5 and 19 percent above the 2003-2015 average, according to NOAA. What the change means for delicate ecosystems and fish stocks is the subject of increasing research attention.

In a presentation in November, Johan Rockström, environmental scientist and director of the Stockholm Resilience Center, reached for scientific euphemism to make manageable the enormous scale of these interlocking changes—and who needs to be thinking about them: “Canada, Russia and parts of the U.S. seem to be the Arctic nations subject to the largest, let’s say, set of diverse regime-shift risks.”

In the long run, every part of the Arctic food web may have to adjust to the warming atmosphere’s byproduct: altered ocean chemistry.

Oceans do humanity a huge favor by absorbing some atmospheric carbon dioxide. However, when CO2 dissolves into water, it becomes a weak acid that, as it accumulates, may strain ecosystems that have evolved for today’s slightly alkaline waters. The change is happening globally, but cold water “acidifies” more quickly than warmer seas.

Arctic land stores about twice as much carbon as the atmosphere. While growing seasons—which are now either longer or newly possible, depending on the exact location—suck in carbon dioxide during the spring and summer, scientists believe the thawing lands are now emitting more carbon than they take in.

Perhaps the most visually dramatic change in the landscape has been occurring in Russia. Warming temperatures have accelerated the rate of natural underground methane leaks. The gas builds up in the soil, forming mounds called “pingoes.” When the pressure becomes too great, the ground explodes, leaving 30 to 40-meter-wide craters.

Seismologists have begun to install sensors in the Russian Arctic to give advance notice of fields ready to blow their top. These local events are a powerful visual example of how the world is changing in dramatic and surprising ways.

Many scientists who study the Arctic say that there’s simply no way such dramatic change at the top of the world can avoid affecting life below it. There’s already a cliche: What happens in the Arctic doesn’t stay in the Arctic.

What’s true about the weather may also be true about the resources of the north, primarily energy and food. For the moment, Arctic and non-Arctic nations alike regularly collaborate on issues emerging at the top of the world. In a sense, they’re haggling politely—for now—over the ultimate renewable resource: geopolitical power.

©2017 Bloomberg News

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