Future Arctic won't look like the Arctic we know now, says report

It may be the end of the Arctic as we know it.

That wasn't the title of the report Key indicators of Arctic climate change: 1971-2017 published Monday in Environment Research Letters, but 47 years worth of data saysit may not be a stretch to go there.

The study, authored by 20 researchers from an international roster of universities and climate research institutes, crunches nearly five decades of data related to nine key elements that define the Arctic.

Taken together the indicators describe, as the report puts it, an "Arctic biophysical system ... now clearly trending away from its 20th century state and into an unprecedented state."

But the end of the Arctic as we know it?

The Arctic is really going to change its face.- William Colgan, Senior researcher at Geological Survey of Denmark and Greenland

"You could say that without too much hyperbole," said William Colgan, a senior researcher at the Geological Survey of Denmark and Greenland, and one of the report's authors.

"The Arctic is really going to change its face. In another generation, we're going to be even more different than we are now. You can expect changes to pick up and accelerate."

This report brings together indicators or measures of climate change often treated in isolation from one another.

Air temperature, land ice thickness, permafrost temperature, precipitation, terrestrial snow cover, sea ice thickness, and tundra greening are among the indicators studied.

The 47-year time frame matches available satellite data. "Arctic," in this study, refers to the region north of 60 degrees latitude to capture the geography of Arctic nations and populations.

In short, according to the study, the Arctic has gotten warmer by 3.1 C in the cold season (October to May) andgreener and wetter; it enjoys less snow cover, contains less land and sea ice, and is subject to greater variations in temperatures and extreme weather events.

Ice thins, sea levels rise,planet tips

The magnitude and rate of change in some cases defies easy conceptualization.

Since 1971, Colgan says 8 trillion metric tonnes of land ice was lost across the Alaskan, Canadian, Greenlandic, Scandinaviananand high Russian Arctic. That ice continues to melt today at a rate of 14,000 tonnes a second.

That's enough mass to tip the earth, Colgan said.

"The planet now points to a slightly different North Pole because we're redistributing too much mass on the earth right now through melting of glaciers, and then letting that water run off into the ocean and get spread around towards the equator."

I think we're beyond the point of arguing whether or not things are changing.- William Colgan, Senior researcher at Geological Survey of Denmark and Greenland

This loss of Arctic land ice is felt around the world as sea levels rise. Between 2003 and 2010, Arctic land ice melt accounted for 48 per cent of land ice to sea level rise.

"We can say with a high degree of certainty that Arctic land ice is the number one line item on the global sea level rise budget," Colgan said.

Arctic snow cover

The duration of Arctic spring snow cover has decreased by more than 30 per cent since 1971, according to the report.

That's a loss of about two to four days of snow cover per decade.

The study links declining snow cover and the rise in extreme weather events with caribou mortality and loss of opportunity for traditional ways of life.

"When you have snow cover you can use a snowmobile, and you can go up and travel easily over the land to get to your hunting grounds," said Ross Brown, a snow researcher with the climate research division of Environment and Climate Change Canada, and one of the reports authors.

"One of the things we're seeing is that this more frequent winter-rain, winter-thaw events happening. That creates ice layers in the snow pack," Ross said.

This means already-threatened caribou may have more difficulty foraging for food locked under ice.

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It's the greenhouse gases

Colgan said that although there have been periods of natural fluctuation in Arctic temperatures, since about 1990 the vast majority of all the change we see in the Arctic is human caused.

Colgan doesn't anticipate any fact-based contradiction of the report's findings.

"I think we're beyond the point of arguing whether or not things are changing," he said. "Now the biggest dissent is whether or not that change is important."

According to a recent U.N. report, significant Arctic climate change is already locked in, even if global greenhouse gas emissions were cut to zero overnight.

But Colgan said cuts made now to bring reductions in line with the Paris Agreement on climate change still matter.

"We know that the momentum in the climate system is going to lead to more warming, and more melting glaciers, and more sea level rise, and more greening of the Arctic, up through until mid-century," he said.

"But then after that, the future really is ours."

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