The reality of climate change is beyond debate, the Times-Dispatch paraphrases Gov. Timothy M. Kaine as saying during the initial meeting yesterday of his commission on Climate Change.
“Gone are the days of debating whether man-made effects exist” with global warming, the Virginian-Pilot quotes him as saying. “Those days are gone.”
The first of the two statements is a non-sequitor. No scientist anywhere, to my knowledge, disputes that “climate change” is a reality. The climate of the earth has varied enormously over hundreds of millions of years, experiencing wild swings between tropical heat and glacial cold.
The second statement is uncontroversial for the most part, except perhaps among right-wing talk radio hosts. There is little dispute that human activities have impacted the climate. The extent of the impact may remain an open question but no serious person would contend that mankind has had no impact whatsoever.
The two statements sound profound but they are so vague as to be meaningless. We’ve heard it over and over that the science of climate change and global warming is “settled” and that there is a “consensus” among scientists. In reality, climatology is a dynamic field with many findings that don’t fit the prevailing paradigm and loads of scientific controversy over narrow questions. Here are how I, as an amateur follower of the debate, break down the issues:
- How rapidly is the climate warming? Yes, virtually everyone agrees that the earth has been warming since the end of the Little Ice Age, which lasted from the 16th to the 19th century. Virtually everyone agrees that the warming trend extended through the 20th century and into the 21st. The big question is, how much? Measuring the “average” temperature of the earth is not an easy task. We’re getting better at it, but measurement is far from perfect. One example: Many measurements are subject to the “heat island” effect. In the United States, many temperature sensors are located in airports. Fifty years ago, the airports were situated in the countryside. Today, those locations have been encroached upon by urban development that can raise the ambient temperature several degrees. It is a matter of some controversy how best to adjust for such trends. Meanwhile, there are many other other assumptions and adjustments embedded in global temperature calculations. Just last year, NASA was forced to make an embarrassing downward adjustment to its temperature record for the years since 2000 after a methodological flaw in its calculations was exposed.
- Are current temperatures unprecedented? In the current cycle, which follows a brief cold spell in the 1960s-70s that spurred fears of an impending ice age, it appears that we have reached levels not seen since… the 1930s. We could well surpass that decade — which immortalized the image of, “It’s so hot you could fry an egg on the pavement” — if temperatures keep rising, but the climate still won’t exactly be “unprecedented.” Average temperatures were just as high during the Medieval Climate Optimum.
- What is causing global warming? The earth has been warming and cooling for billions of years. There are many non-human factors at work, including minor shifts in the earth’s orbit and cyclical outpourings of solar radiation (which affect the earth’s magnetosphere, which in turn effects the bombardment of cosmic radiation, which in turn effects cloud formation.) The question is: How much of the warming we are seeing now is the result from natural, cyclical processes and how much results from mankind’s release of C02 and other greenhouse gases? Teasing apart the impact of natural vs. manmade influences is exceedingly difficult.
- Global warming and sea levels. While the vast majority of climatologists are certain that planet is warming (though they don’t all agree on how much), it is far from clear what the impact will be. Widely feared — and a key justification for Virginia’s climate change commission — is the belief that icecaps will melt and sea levels will rise. While there is some scientific evidence for this view, there are many complicating factors. Rising temperatures may increase precipitation (e.g. snowfall) on major icecaps such as Greenland and Antarctica. Water (in the form of ice) could conceivably accumulate faster in the high, cold plateaus faster than it melts along the lower, warmer edges of the plateaus. The melting of the polar ice cap, by the way, would only contribute marginally to rising sea levels — to the extent that ice takes up a slightly larger volume than liquid water. My advice to polar bears: Move to the Greenland plateau. (Just kidding.)
- Global warming and the biosphere. Of particular interest to the Virginia study group should be the impact of Global Warming on… Virginia. As I understand the Global Warming models, manmade warming is expected to be most pronounced in cold, dry regions. Most, temperate regions such as Virginia should see less temperature change. It would be helpful to know to what extent will temperatures rise in Virginia, and to what extent will rising temperatures cause a change in habitat, affecting all manner of species? We should know to what extent indigenous species are vulnerable to temperature changes of the expected magnitudes. I have seen nothing on this. Another interesting question is the impact of higher C02 levels on plant growth. C02 is to plants what oxygen is to animals. If higher C02 levels promote plant growth, as I have read, this would be a good thing, I would think — unless you’ve got a kudzu infestation in the back yard.
- What can be done to avert Global Warming? Once we begin asking this question, we move out of the realm of science entirely and into the realm of public policy and ideology. There is widespread political support in Virginia for limiting greenhouse gas emissions, particularly among segments of the population comfortable with the idea of government exerting more control over the economy. But there are two sides of the climatic equation. Not only do humans emit more greenhouse gas than we used to, we are chopping down our rain forests, the world’s major repositories of C02. Why is the focus in Virginia exclusively upon reducing emissions? Why aren’t we asking what we can do to increase C02 absorption, possibly through reforestation?
The biggest mistake we can make is to assume that the science is settled, that we “know” what the impact of Global Warming will be upon Virginia, and that we have to do something, anything, as in, intervene in the economy, to avert the approaching calamity. Climate change is an issue worth studying. But I see no justification yet for panicking into rash and ill-considered action.
Regarding public policy, I think that free-market/fiscal conservatives can find some common ground with greenies on the Global Warming debate. Everyone should favor energy conservation, especially if energy conservation projects can be justified on a Return on Investment basis. State and local governments should be encouraged to conserve energy as a means to cut the cost of government… as well as to save the planet. Virginia should implement transportation policies that encourage people to drive less — as a strategy for reducing traffic congestion and cutting the pressure for more spending on roads… as well as to save the planet.
If the Climate Change commission takes that approach, I’ll feel a lot more comfortable.
