Yesterday, I was having breakfast with a distinguished glaciologist from the University of Alberta in Edmonton, Dr. Martin Sharp. He gave me some astounding beta about glaciers in the Yukon.
If you ever fell under the spell of Jack London stories, sagas of the Klondike Gold Rush, or the TV show “Sergeant Preston of the Yukon,” you know that the Yukon is the epitome of the cold and frozen Canadian northlands. Not any more.
Martin and his colleague, Nick Barrand (who now works for the British Antarctic Survey), collected aerial photos of Yukon glaciers documented during the International Geophysical Year 1957-1958 and compared them to others produced during the International Polar Year in 2007-2009.
Here’s what they found:
1 glacier advanced.
523 glaciers disappeared.
876 glaciers retreated.
22% of the area covered by ice 50 years ago is now ice-free.
OMG!!! Even to me, living and breathing the glacier retreat story of our planet eight days a week, those kinds of numbers are incredible.
What happened??? Glaciers are great bermometers (my word, a combination of “barometer” and “thermometer”) of regional climate.
The northwestern part of our continent—Alaska, the Yukon, British Columbia—has warmed. In the past half century, winter temperatures in the Yukon are up 3.5ºF, and summer temperatures have risen nearly 2ºF. Snowfall is down and the freezing level has gone higher. So the ice has retreated.
Globally, says Sharp, all the mountain glaciers and icecaps (the sort of large-ish ice bodies found on the Alaska coast or Baffin Island) are losing about 450 billion tons of ice per year. That counts for about half of current, ongoing sea level rise. The enormous ice sheets of Greenland or Antarctica contribute the rest. By the time today’s schoolchildren retire in Baja or Florida, sea level will have risen at least a foot and a half. Three feet is a serious possibility; more is entirely conceivable.
Any mulehead can understand what the ice is saying: the climate is changing. It isn’t a computer model or a projection. It’s real. It’s measurable. And it’s astounding. Tell your climate skeptic friends next time you get a chance.
For more information, see N.E. Barrand and M.J. Sharp, “Sustained rapid shrinkage of Yukon glaciers since the 1957–1958 International Geophysical Year.” GEOPHYSICAL RESEARCH LETTERS, VOL. 37, L07501, doi:10.1029/2009GL042030, 2010