A simple analogy may make this point clearer. Suppose we learned tomorrow that there was one chance in 10 that a huge asteroid, recently discovered, was going to crash into the Earth in five years, killing a billion people and raining debris in such amounts as to blot out sunlight significantly for a year. (A similar event is thought to have led to the extinction of the dinosaurs.) Would anyone in his or her right mind argue that, because we couldn’t prove that human activity was responsible for the asteroid, there was no reason to hurt our economy by spending hundreds of billions of dollars firing nuclear-tipped rockets at it to destroy it or alter its course? Yet that’s exactly what the denialists are trying to argue now, in the case of a climate crisis that has at least an equal probability of globally devastating consequences.
True, our climate models can’t predict with certainty that the steps being considered in Copenhagen will retard, halt or reverse the current warming trend. But they represent all we can do at the moment. If global warming is being caused primarily by greenhouse gases, as many thoughtful scientists believe, then the Copenhagen measures will do a lot. If global warming is actually caused by, say, sunspots or something similar, reduction of emissions may not do so much. But everyone agrees that the Copenhagen strategy will do something, and my point is that something simply has to be done.
I hope you see now why I started this essay as I did. We should not be debating whether human activity is responsible for global warming or not. Given that even the denialists and skeptics have conceded the fact of global warming, the debate should be over the most effective means of doing something about it. This means, I am afraid, not just limiting our discussion to controls on CO2 emissions. We need to look seriously at developing technologies for carbon sequestration, alternative fuels and carbon-neutral technologies for transportation and energy production. Much of this will involve engineering microorganisms and plants, so genomics is going to be very important in enabling these technologies as we grapple with the crisis. I also see no escape from at least investigating ideas for geoengineering— solutions involving deliberate changing in sunlight absorption, carbon capture and temperature reduction on a continent- or planetwide scale. My gut reaction to geoengineering is that it is a terrible idea, born as much of hubris as desperation, that should be shelved permanently because we will never have the kind of models that would guarantee beforehand that it could be done safely. But the fact is, we don’t know what we don’t know when it comes to such projects, and, given the severity of the climate crisis, if someone wants to propose that we should at least begin to study such solutions to determine the extent of our ignorance and the possibility that we might someday be able to employ them, I wouldn’t say no.
So, the next time you find yourself in a debate with someone over the climate crisis, and they say that we shouldn’t reduce CO2 emissions because there is no definitive proof that manmade greenhouse gases are the cause of global warming, respond by saying, “Then if an alien race were threatening to exterminate mankind, you wouldn’t do anything to try to stop them because human activities weren’t the cause of the alien invasion, is that right?” And they’ll reply, “Of course not! But this is completely different.” And you’ll say, “No, it’s not. Let me explain why.”
Given the harsh climate that has developed around the subject of global warming, you probably won’t convince them that they’re wrong. But at least you’ll be having the right argument.
* This article originally appeared in Genome Biology (2009) 10, 115 and was reprinted with permission from BioMed Central.