This is not a good post. I’m mostly venting a little frustration from this evening (and not all of it from the subject of this entry).
I couldn’t avoid references to an article in the CS Monitor today. I must have come across half a dozen of them.
Over the past 20 years, southern sea ice has expanded, in contrast to the Arctic’s decline, and researchers want to understand why. Many climate-model experiments show the Arctic responding more rapidly than Antarctica as global warming kicks in. But after looking at the latest projections from the Intergovernmental Panel on Climate Change, “Arctic sea ice is well ahead of the models, and Antarctic sea ice is well behind what the models project,” says Stephen Ackley, a polar scientist at the University of Texas, San Antonio.
Two things immediately jump out for global warming skeptics (as I’ve seen already): the expansion of sea ice in the southern hemisphere, and observations that don’t precisely fit climate model predictions. These tid-bits are juicy for obvious reasons, even if I think they’re misleading. The article actually addresses findings that are worrisome, but they’re harder to grasp or explain than “south pole ice grows.”
Two things from the article jumped out at me: they were talking about SEA ice, and they seemed to be referencing the amount of AREA covered by ice.
Maybe I’m way off base here – that or I’ve completely misunderstood the article, but if they’re just talking about sea ice, that’s just one piece of the puzzle – and the least worrisome. As I’ve referenced before, NASA has surveyed Antarctic ice as a WHOLE (ice accumulated on land as well as at sea), and determined that as a whole it’s diminishing (not growing, as the title of the Monitor article perhaps misleadingly suggests). Don’t get me wrong, the amount of sea ice in the south is interesting, but it’s half of the story (or less).
Sea ice is generally at sea. If it’s just an accumulation of frozen precipitation from water evaporating from oceans – or more directly, frozen sea water – there’s not as much change in ocean levels. You’re just changing it’s state from liquid to solid. (I think this may actually increase it’s volume a little, but not a lot. I think ice is less dense than water – which is why it floats – and why it expands when it freezes.) The much bigger problem is the land ice, which we very much want to stay on land – and not decrease in mass – given where the shedded mass likely goes.
So if the Antarctic ice is covering more area, how can their be less of it? As it happens, matter often can be measured in three dimensions: length, width, and height (or thickness). Area is a two dimensional measurement, but ice can be measured in three. Antarctic ice could simultaneously be spreading out – and therefore take up more area, but thin out sufficiently to take up less volume, and have less mass.
It’ll be interesting to see if there’s much chatter about this online, and see where the discussions go.
Well, it’ll be interesting to me anyway. If nothing else, I may find out how much crap I’m full of.