Tuesday, May 01, 2018

Melting Arctic Sends a Message:  Climate Change Is Here in a Big Way - By Mark Serreze, University of Colorado

Scientists on Arctic sea ice in the Chukchi Sea, surrounded by melt ponds, July 4, 2010. (Image Credit: NASA/Kathryn Hansen) Click to Enlarge.
Scientists have known for a long time that as climate change started to heat up the Earth, its effects would be most pronounced in the Arctic.  This has many reasons, but climate feedbacks are key.  As the Arctic warms, snow and ice melt, and the surface absorbs more of the sun’s energy instead of reflecting it back into space.  This makes it even warmer, which causes more melting, and so on.

This expectation has become a reality that I describe in my new book Brave New Arctic.  It’s a visually compelling story:  The effects of warming are evident in shrinking ice caps and glaciers and in Alaskan roads buckling as permafrost beneath them thaws.

But for many people the Arctic seems like a faraway place, and stories of what is happening there seem irrelevant to their lives.  It can also be hard to accept that the globe is warming up while you are shoveling out from the latest snowstorm.

Since I have spent more than 35 years studying snow, ice and cold places, people often are surprised when I tell them I once was skeptical that human activities were playing a role in climate change.  My book traces my own career as a climate scientist and the evolving views of many scientists I have worked with.  When I first started working in the Arctic, scientists understood it as a region defined by its snow and ice, with a varying but generally constant climate.  In the 1990s, we realized that it was changing, but it took us years to figure out why.  Now scientists are trying to understand what the Arctic’s ongoing transformation means for the rest of the planet, and whether the Arctic of old will ever be seen again.

Evidence Piles up
Evidence that the Arctic is warming rapidly extends far beyond shrinking ice caps and buckling roads.  It also includes a melting Greenland ice sheet; a rapid decline in the extent of the Arctic’s floating sea ice cover in summer; warming and thawing of permafrost; shrubs taking over areas of tundra that formerly were dominated by sedges, grasses, mosses and lichens; and a rise in temperature twice as large as that for the globe as a whole.  This outsized warming even has a name:  Arctic amplification.
Seeing Is Believing
Climate change really hit home for me when when I found out that two little ice caps in the Canadian Arctic I had studied back in 1982 and 1983 as a young graduate student had essentially disappeared.
Today it seems increasingly likely that what is happening in the Arctic will reverberate around the globe.  Arctic warming may already be influencing weather patterns in the middle latitudes.  Meltdown of the Greenland ice sheet is having an increasing impact on sea level rise.  As permafrost thaws, it may start to release carbon dioxide and methane to the atmosphere, further warming the climate.

Read more at Melting Arctic Sends a Message:  Climate Change Is Here in a Big Way

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