In science, nature bats last. We can spin all the theories we like, throw curves at the media to draw attention (i.e., funding) to our favorite issues or even toss knuckleballs at unruly congressional hearings, but in the end reality will intervene.
That's the way things must play out on the field of environmental science. So, for example, the newspapers can bludgeon us with daily stories of global warming horrors, and yet life goes on. Maybe even getting better, some might argue, what with the severity of winter slightly diminished, the growing season slightly lengthened and dramatic increases in food production and human longevity. Eventually people realize that there is a phenomenal disconnect between what they read and who they are.
Pollsters tell us that this is happening. Despite all the current noise, "environment" ranks way down on the threat board in about fifth or sixth place. Within that category, global warming doesn't come close to clean water. People are clearly much more concerned about $2.00 per gallon gasoline than they are about the fact that burning it makes the air less cold.
The problem is that global warming is getting old. The first time it led a network news show was in October 1983 -- 17 years ago. Since then, the mean surface temperature has risen about 0.20ºC. (Computer models from that era predicted that the warming would be 0.68ºC, more than three times what was actually observed.) Temperatures rose at the same rate in the 13 years prior to 1983, giving us three decades, or nearly half a lifetime, of dreaded heating.
In the last three decades, world production of wheat, corn and soybeans combined rose from around 1800 kilograms/hectare to around 3200, or 78 percent, while population rose 50 percent. In other words, there is now considerably more food produced per living person. Life expectancy in the United States rose about seven years, or one-tenth of a lifetime. Don't even ask about the Dow Jones. These are the unvarnished truths about the human condition vis-à-vis global warming.
Remember the "Ozone Hole"? It's been around almost exactly the same length of time. Unlike global warming, that hole concerned us sufficiently that we "did something" about it, instituting a ban on the production of some chlorofluorocarbons (CFCs) that we thought caused a large part of the problem.
Well, the ozone hole is back and is proving itself about as meaningful as global warming. NASA scientists recently announced that, despite falling concentrations of CFCs, ozone depletion is accelerating in the North Polar stratosphere in late winter and early spring. That's the season during which annual depletions peak, because the sun, which catalyzes the formation of ozone, has been below or near the horizon for months. When it gets high enough in the sky to cause sunburn, ozone is replenished.
NASA now tells us that ozone is still being depleted around boreal sunrise, despite the reduction in CFCs, because the same changes in the greenhouse effect that cause global warming also happen to induce stratospheric cooling, which hastens ozone depletion. This totally plausible theory will ultimately serve to ho-hum away yet another environmental disaster.
That's because we are merely returning the atmosphere to its more "natural" greenhouse effect, a state that has characterized much of the history of large-scale life on the planet. While we will hear (increasingly, as Earth Day 2000 approaches) that soon carbon dioxide levels will be higher than they have been for a few million years, the fact is that those levels were much higher in (at least) the previous 290 million years, and that they dropped concurrently with the global cooling that created the ice ages. Be aware that correlation here does not imply causation.
All of this means that when the planet was teeming with dinosaurs, cycads and whatever else fossilized itself into General Motors, the earth's natural greenhouse effect was several times greater than it is today. Which means that the stratosphere was several degrees colder. Which means that every time a big volcano went off (and there were more on a younger earth) enough chlorine had to go into the stratosphere to blow a hole in the ozone.
Nature really does bat last. She survived through all those innings when ultraviolet radiation rained down through the naturally low stratospheric ozone. In fact, she prospered, and, as a result, we evolved.