Climate Change

How harmful is the current, uncommon rate of increase of global temperature? I ask not to cast doubt on whether it can ever be harmful, for surely it can. But unless we know how harmful and when, how can we know the disease is worse than the cure?

I ask because global temperature has risen about two thirds of a degree Celsius since 1900, only about half of which is attributable to mankind's actions (previous to 1950 or so, solar irradiance best explained global temperature). I cannot think of a hypothetical situation wherein less than a degree of ambient temperature could make a significant difference to anything, even if the change had occurred instantly.

This thought occurred to me while rereading this rebuttal to the climate skepticism argument that a warmer world could be better, part of a larger (and very well-written and reasonable) series entitled How To Talk to a Climate Skeptic. In this particular rebuttal, he argues quite reasonably that it is the rate of change, not the resulting temperature, that puts the ecosystem at risk.

I am reminded of driving a car. You can go extremely fast in a car, but you don't suffer the consequences until you crash. The rapid acceleration of crashing is entirely out of proportion with anything a car can achieve otherwise. 0 to 60 in 3.5 seconds, then 60 to 0 in a few hundredths. By analogy, current global temperature change is a car crash.

However, with car accidents there have been extensive studies into what G-forces for what durations cause what harm. We know what safety features to advocate (seat belts, air bags, crumple zones, etc) because we have measured their effects and optimized their design. The prescriptions provided for global temperature control are not based on careful measure and experiment, but are based solely on preventing what is already happening. This "Anything but this!" mentality is just as destructive as the head-in-the-sand, "Global warming is a conspiracy!" mentality. There are always worse things than this, whatever "this" could possibly be, and we cannot currently be responsibly confident our prescribed solutions are not among those worse things. Not while the costs both of the disease and the cure remain widely unknown.

That same advocate of climate change danger, Coby, mentions that the Great Dying, the most complete mass extinction in geologic history, is thought to have been caused by rapid climate change 250 million years ago. The Great Dying took place over about a million years. Even if the modern global temperature increase has something in common with that ancient one, there's certainly no reason to believe the current temperature increase is many thousands of times times faster than back then; it's not even significantly faster than the 1900-1950 solar-forced warming, which presumably occurred rather similarly 250 million years ago. By that comparison, we have half a million years or so to correct the global temperature increase we're now seeing. Perhaps 10,000 years if we want to nip this in the bud right away.

I'm not comforted by that bad reasoning, but I'm certainly not frightened by the bogeyman of a modern mass extinction event. I believe that science is giving us increasing awareness of the changes we induce on our planet, but we seem superstitiously afraid of those changes. Not everything artificial is the end of the world, despite the Green Party's press releases.

Perhaps we do need to act dramatically and now to stop global warming, but despite my repeated perusal of various climate change action advocates' arguments and sources I have yet to see what and why and how much. Whatever governmental policy you prescribe, inaction included, there has to be a reason for it. That's the weak point in the debate, not the science.