I've been slow on the blogging here lately....maybe sometime I'll get around to writing about the whole saga of the past couple months. But not yet.

Today I'd like to draw your attention to this little gem of a commentary (via Amy Alkon, the blogger I love to hate) about global warming.

Here in the Twin Cities, for example, we've had only one night with solidly below-zero temperatures so far this winter (-8 at our home, a week ago), and it's looking like that may have been the coldest night of the season. Normally we get at least one or two hard arctic blasts, where temperatures dip well below zero for a week or so at a stretch, and we usually bottom out in the teens below zero. Sometimes we kiss -20 for a moment.

We've also had very little precipitation, with the storms all tracking well south of here. Parts of New Mexico have gotten more snow than Duluth.

So when the climatologist does the radio call-in show, someone always asks, "Is this weird weather the result of global warming?"

The scientifically nuanced answer always goes something like this: "We can't really tell if one season's weather is the result of global warming or not, but we think the climate is heating up over the long term." Global warming true believers don't like this, because it sounds wishy-washy. Skeptics don't like it, because it says the Earth is getting warmer. Neither side seems particularly willing to consider that the actual truth probably lives somewhere between the "Greenland is getting colder" camp and the "Humans are going the way of the dodo" alarmists.

Here's the unvarnished truth:

Fact 1: The Earth is getting warmer. This is measurable, and while there are local changes against the trend in places, all the best and most careful data show that the planet, as a whole, is ever so slightly warmer today than it was 25 or 50 years ago.

Fact 2: Atmospheric carbon dioxide is higher today than it was 100 years ago, has been steadily rising for as long as records have been kept, and is probably higher today than any time in the past several thousand years. Methane has also been rising, but the records aren't as good, and methane doesn't last as long in the atmosphere anyway.

Scientific Conclusion 1: The increase in the Earth's temperature is likely because of the increase in carbon dioxide (and methane). With something as complex as and entire planet it can be hard to be 100% certain of cause and effect, but the theory is sound and the effects are what we'd expect. So it is a reasonable conclusion--and there aren't many credible alternative explanations for the observed temperature increase.

Scientific Conclusion 2: The increase in carbon dioxide (and methane) is almost certainly because of human activities, especially the burning of fossil fuels. All that carbon dioxide has to come from somewhere, and the number of possible somewheres is very limited. It is a fact that we've been digging up ancient deposits of organic material for over a century and burning it at a tremendous rate, which is just about the only source anyone has been able to suggest for where all this stuff is coming from. Again, it can be hard to know with 100% certainty (it isn't like the carbon dioxide from nonhuman sources is a different color), but there simply aren't many credible alternative explanations for the observed data.

Unsupported Malarky 1: "We're all doomed!" People are always drawn to the dramatic, catastrophic scenario--even when the odds are slim. In truth, the Earth has suffered far greater environmental catastrophes in the past and generally come out of them OK. Humans are a remarkably adaptable species--even more so now that we have tons of technology at our disposal--and we've survived repeated ice ages and subsequent warming in the past. The worst case scenario is likely a generation or two of mass displacement, large-scale population shifts, extinction of some charismatic megamammals like the polar bear, and then....we adjust. Not to be too flip about it, but the human race survived the extinction of the wooly mammoth (also likely because of human activity, by the way), and we'll survive the loss of other species as well. (This is the worst case scenario, by the way--the reality is likely to be somewhat milder.)

Unsupported Malarky 2: "If we're not doomed, then there's no need to worry." People who think there's no need to plan for the future are just as mistaken as the doomsayers in the long run. Even if you are skeptical about the reality or severity of global warming, there's no denying the fact that fossil fuels are a limited resource and in a century or so we will be forced to find alternate energy sources as even the coal starts to get scarce. So switching to low-carbon energy is simply a fact we'll have to deal with for one reason or another, and pretty soon as measured by the grand sweep of history.

Speaking of the Grand Sweep of History: Roman civilization lasted about 1,000 years, from the beginning of the Republic to the end of the Roman Empire. Imperial China lasted about 2,000 years, and the ancient Egyptian civilization lasted something like 3,500 years. In contrast, the era of fossil fuels, from the beginning of the Industrial Revolution until we run out of economically extractable coal, oil, and gas will only last 400-500 years. When future historians write about our time, it may be notable for many things, but the longevity of fossil fuels as an economical energy source will not be one of them.