Sierra Summit

Conversations and observations about California's mountains

October 22, 2008
Climate Change Denial - Alaska glaciers - Fact and fiction
Not long after my recent article on the receding glaciers of the Sierra Nevada appeared in the Bee, I received an e-mail from a reader clearly skeptical of global warming. 
"Now, Mr. Knudson, since you have run this article, will you also write and run an article telling the public about the thickening glaciers in Alaska?" he wrote.  "I think it would only be fair that you research that story and publish it!"
Fair enough. So I called up Bruce Molnia, a veteran U.S. Geological Survey research geologist  and author of the comprehensive new book, Glaciers of Alaska. 
"More than 99 percent of the glaciers in Alaska have a long-term trend of rapid retreat, thinning and stagnation," Molnia told me.  "And that 99 percent continue to retreat." 
Many, though, did thicken in their upper reaches this year as a result of heavy snowfall last winter and cooler weather over the summer. "But thickening  does not translate into growing," Molnia cautioned.  "And this summer was still pretty dramatic in terms of the rate of melting of many glaciers."
Ironically enough, the thickening - retreating flap began with Molnia himself, in particular with comments he made about the heavy snow accumulation on some glaciers in an article in the Anchorage Daily News. Very quickly, he said, global warming skeptics - including talk radio host Rush Limbaugh - were seizing upon his comments and tweaking them to fit their own agendas.
"I saw individual phrases strategically pulled out of individual paragraphs to give the impression that glaciers were not melting and ... that we are being sold a bill of goods on climate change," he said. "I was fascinated at how aggressively this was picked up and broadly it was circulated." 
"I think they are grasping for straws," Molnia said of the skeptics. "So much of the science community has come around, and even some of the more conservative Republicans  have come around and said: Yes we recognize the climate is changing."
In all, Alaska has roughly 2,000 large glaciers, Molnia said. Only about a dozen - less than one percent - are advancing, largely because of heavy snowfall in the upper portions of their watersheds. The remaining 99.4 percent are retreating. 
"Alaska as a whole is warming and these glaciers are accelerating their melting," Molnia said.
(For visual evidence, look at the photos of the Muir glacier in Alaska above. The first was taken by William O. Field in 1941; the second was taken by Molnia himself in 2004.)
And even though some glaciers began receding as long ago as 1750 from natural temperature increases, the driving force behind today's meltdown is global warming caused by the the build-up of greenhouse gases from the burning of fossil fuels, Molnia said. 
"What we're seeing is that anthropogenic  effects are accelerating the rate of melting and probably have been a factor for the better part of a century," Molina said.
To read more about Molnia's new book Glaciers of Alaska, click on this link:
And for a press release about the book, check out this link:

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About Sierra Summit

The Author
Tom Knudson lives in the Sierra Nevada and travels widely throughout the range. His hobbies include fly-fishing, backpacking and cross-country skiing. He is the recipient of numerous journalistic awards, including two Pulitzer Prizes, one for a 1992 Sacramento Bee series "Sierra in Peril," a watershed work about environmental threats to the mountain range. E-mail Tom at

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