The Science is Settled

This post makes the case for why the science is settled on climate change. Of course, interpreting this statement, which once had its own Wikipedia page, depends entirely upon what one means by "the science." Here I am going to define "the science" as that science of the global earth system which is necessary to open up the possibility that decision makers may wish to consider action on greenhouse gas emissions. Any decision on what action (if any), when, at what costs will result from many factors beyond climate science and different people who decide to act together will necessarily have vastly different views about the state of the science and its importance.

What is this settled science? Thomas Friedman gets it absolutely correct in his NYT column today (emphasis added):

This is not complicated. We know that our planet is enveloped in a blanket of greenhouse gases that keep the Earth at a comfortable temperature. As we pump more carbon-dioxide and other greenhouse gases into that blanket from cars, buildings, agriculture, forests and industry, more heat gets trapped.

What we don’t know, because the climate system is so complex, is what other factors might over time compensate for that man-driven warming, or how rapidly temperatures might rise, melt more ice and raise sea levels. It’s all a game of odds. We’ve never been here before. We just know two things: one, the CO2 we put into the atmosphere stays there for many years, so it is “irreversible” in real-time (barring some feat of geo-engineering); and two, that CO2 buildup has the potential to unleash “catastrophic” warming.

When I see a problem that has even a 1 percent probability of occurring and is “irreversible” and potentially “catastrophic,” I buy insurance. That is what taking climate change seriously is all about.

Friedman is absolutely right about what we know and what we don't know. Debates over action get wrapped up around debates what we know and what we don't know, and these debates are unlikely to be settled any time soon, whether within the scientific community or among the broader public.

The fulcrum on which action rests to decarbonize economies and improve adaptation will not be science, but everything else. The more science is used as such a fulcrum -- especially among activist scientists -- the more potential damage to science itself.

So the next time that you hear that the "science is settled" you can understand that it is settled, but the way that it is settled doesn't provide any answers to questions of politics. Thomas Friedman gets this point:

If we prepare for climate change by building a clean-power economy, but climate change turns out to be a hoax, what would be the result? Well, during a transition period, we would have higher energy prices. But gradually we would be driving battery-powered electric cars and powering more and more of our homes and factories with wind, solar, nuclear and second-generation biofuels. We would be much less dependent on oil dictators who have drawn a bull’s-eye on our backs; our trade deficit would improve; the dollar would strengthen; and the air we breathe would be cleaner. In short, as a country, we would be stronger, more innovative and more energy independent.