I've been meaning to write a last post about measuring glaciers at Denali National Park. A ridiculous post, by a global warming denialist who won't put his money where his mouth is, did have the function of reminding me that I need to write it.
The denialist noted that some glaciers weren't retreating and thinks that disproves global warming. If he had read more than the headline of the article he linked to, he would have realized that climate change can also increase snowfall in some places, and even cause cooling in some places, so it's no surprise that some glaciers would advance.
Most glaciers are retreating though, including all four glaciers we measured this summer. What surprised me though was how little they retreated - the bottom elevations of the glaciers were 100 to 300 feet higher than the ones shown on our topographic maps, which date to the 1950s. If these had been giant glaciers, that level of retreat would be meaningless, but these glaciers were relatively small (two-three miles long, roughly). Still I was surprised at how little retreat had occurred in fifty years.
The only thing I could add is that in the six years I worked at Denali, precipitation was far above the historical average. If that stayed the case, it's not hard to see how the extra snowfall could partially balance out the extra warmth.
Anyway, it should be interesting someday to find out what the overall trend is for all the Denali glaciers.