(Charles Platt is a guest blogger)
At the risk of stimulating outrage, I'm going to ask some questions about climate. No one disputes that planetary warming occurred during the second half of the twentieth century; the question is whether it was primarily anthropogenic (i.e. caused by human beings). The Intergovernment Panel on Climate Change (IPCC) claims that the debate on this issue is over. I'm not so sure anymore.
I'll begin with The Deniers by Lawrence Solomon, which I regard as the most important book that I read in 2008.
Solomon is an old-school environmental activist who dislikes nuclear power, wants to save rainforests, yet started to doubt the environmental party line on climate change after he made contact with a series of highly credentialled scientists, all of whom have been labelled with the pejorative term deniers. They accept that warming has occurred, but don't believe it's as simple as the IPCC makes it seem to be.
Several are convinced that our lack of knowledge about factors affecting cloud formation in the upper atmosphere makes an accurate warming model impossible. Many feel that recent warming is just a cyclical recovery from a “little ice age” and may have little to do with human activity. Some conjecture that we are already starting to descend into a new cooling period which will be far more difficult to deal with than warming. Whether they're right or wrong is debatable; the point is that a debate does exist, and those on the skeptical side should not be ignored, ridiculed, smeared, or threatened with career damage.
The book presents a variety of data. I lack space here to explain why each item is supported by at least some evidence.
—CO2 levels may have been as high 11,000 years ago as they are today.
—Air bubbles in preindustrial Antarctic ice indicate that CO2 levels in the 1890s were almost as high as in the 1950s.
—Sea levels have been rising naturally for 16,000 years and have probably fluctuated by up to two meters during the past 1,000 years alone.
—While portions of the Antarctic are melting (and have attracted publicity), other portions are gathering ice (and have been ignored by the media). The overall loss of ice is probably minuscule. As for the Arctic, since it consists of floating ice, it would not cause sea levels to rise even if it melted completely.
—The planet Mars has been experiencing its own global warming, in sync with ours, unprompted by any human activity.
—The greenhouse effect is a logarithmic function; in other words, each linear increment in the volume of carbon dioxide causes a progressively smaller increase in temperature. We have already reached the point of diminishing returns.
—Many measurements of global temperature have flattened out during the last decade. The planet is probably cooler now than when George W. Bush took office.
—The so-called “hockey stick” curve, showing temperature suddenly increasing at an exponential rate after a long period of stability, has been discredited by some statisticians to the point where even the IPCC has backed away from using it.
Human activity may indeed be affecting the climate, but after reading the calm, methodical statements by the “deniers,” I'm no longer willing to believe that anyone has a complete model of the complex, chaotic systems that determine global temperature, and I regret that the simplistic fear-metaphors used by people such as Al Gore have tended to demonize those who simply feel that the evidence, at this point, is still inconclusive.