Yes, I know you’ve all heard that we’ve had “record” refreezing of Arctic ice. Big shock there. We had record melting followed by a temporary cooling La Niña event. What those denier/delayer-1000 talking points don’t tell you is that the refrozen ice is very thin and still at record low levels following the staggering ice loss this summer.
To set the record straight, on Wednesday, the National Snow and Ice Data Center and NASA had a teleconference to show the surprising and alarming new data from NASA’s ICESat satellite, which revealed over the past year “the steepest yearly decline in perennial [i.e., old, thick] ice on record” (click to enlarge):
The key point is that ice volume is ice area times ice thickness. The seasonal ice (1 year old or newer) is thinner and will quickly melt away and disperse in the wind. This is global warming, folks:
On March 18 the scientists said they believe that the increased area of sea ice this winter is due to recent weather conditions, while the decline in perennial ice reflects the longer-term warming climate trend and is a result of increased melting during summer and greater movement of the older ice out of the Arctic.
The Washington Post had a must-read story on this yesterday:
“Because we had a cold winter, the public might think things have gotten better,” said Walter Meier of the National Snow and Ice Data Center at the University of Colorado at Boulder. “In fact, the loss of the perennial ice makes clear that they’re not getting better at all.“
The surprising drop in perennial ice makes the fast-changing region more unstable, because the thinner seasonal ice melts readily in summer …
Flying over the Arctic, one might perceive the sea ice cover as broad, Meier said, but that apparent breadth hides the fact that the ice is so thin. “It’s a façade, like a Hollywood set,” he said. “There’s no building behind it.”
What a perfect metaphor for the delayers. Their arguments seem solid and impressive, but it’s all a façade.
All of this thinning data comes comes on the heels of the February data reported from NOAA’s National Climactic Data Center, which pointed out that the area of Arctic ice is still historically small:
… the February 2008 Northern Hemisphere sea ice extent, which is measured from passive microwave instruments onboard NOAA satellites, was below the 1979-2000 mean, but greater than the previous four years. This was the fifth least February sea ice extent on record. Including 2008, the past five years had the least February sea ice extent since records began in 1979. Sea ice extent for February has decreased at a rate of 2.8 percent/decade (since satellite records began in 1979) as temperatures in the high latitude Northern Hemisphere have risen at a rate of approximately 0.37 degrees C/decade over the same period.
The planet is warming, and the surface is being transformed.
All of you delayers out there who are so sure that we are in a cooling and ice-refreezing trend, I await your acceptance of my bet: the Arctic Sea will be at least 90 percent ice free by 2020. Absent any takers this year, I can only assume you all don’t actually believe the nonsense you are spouting.
This post was created for ClimateProgress.org, a project of the Center for American Progress Action Fund.
