The twelve men who walked on the Moon are heroes. I have no doubt in my mind about that: the risks they took to stand on the surface of another world were fiercesome, and no matter what their fortitude is not in doubt. I've met many of them at various meetings, and quite liked them. But that doesn't make them infallible, of course. I've written about Apollo 14's Ed Mitchell diving headlong into antiscience (as well as here, here, and here) for example. And now I fear I must add Apollo 17's Harrison Schmitt to the list. I hate to do this, since he is an advocate for space travel and was the only classically-trained scientist to walk on the Moon (he's a geologist). However, he's a climate change denialist. And while everyone is entitled to their opinions, facts are not negotiable. And this is now doubly important since Schmitt was recently appointed to run New Mexico's Department of Energy, Minerals, and Natural Resources, where he will have to make decisions directly related to that state's contribution to climate change.
Apparently, he's been using blatantly wrong information to support his arguments. My Discover Magazine co-blogger Chris Mooney gives an overview of this on DeSmogBlog, but the real meat of Schmitt's claims is pretty handily debunked by Scott Mandia and again by John Cook. There's also a pretty brutal treatment of it by Richard Littlemore at DeSmogBlog as well. In a nutshell, Schmitt has claimed that arctic sea ice is growing in extent, and in 2009 was back to levels seen in 1989. There are two problems with this claim. The first is that it's wrong; Schmitt used cherry-picked data from both of those years that made it seem as if the coverage of ice had grown, but in fact when you look at the monthly and yearly averages, it's clear the extent of ice dropped by several percent. In fact, this last January had the lowest sea ice extent for that month since at least 1979!
The second problem is just as bad: sea ice extent is not a good measure of warming; instead, volume is a much better indicator. You can cover a lot of area of the arctic with ice, but if it's thin ice it'll melt in the summer. If, on the other hand, the ice is thicker (has more depth or volume) then it won't melt as readily. So saying the ice covers more area -- even if true which it clearly is not -- doesn't mean much, because a single particularly cold winter can freeze the surface water, but that'll all melt easily once summer hits. However, if the Earth is warming, then you'd expect the volume of ice to decrease, since the increasing temperatures will actually affect water temperatures, melting the ice below the surface. And as the articles by both Mandia and Cook linked above show, that's what's happening. The extent of sea ice fluctuates with season as expected, but the volume of sea ice is steadily decreasing -- in fact, the trend is that we're losing 3500 cubic kilometers of arctic ice per decade! Not only that, but a more careful examination of sea ice extent shows that over time (many years as opposed as season to season), it's decreasing as well. Again, if the world is warming that means longer summers and shorter winters, so even the maximum area of surface ice measured every year will wane. This isn't exactly, pardon the expression, rocket science. The graphs are pretty clear. Whether you think global warming is manmade or not, the fact of the matter is it's occurring. We're experiencing it right now, and all this noise and distraction and, frankly, distortion of the data won't change that fact. Walking on the Moon is a magnificent achievement, but it doesn't make you any more likely to be right when it comes to the climate.