The Institute of Physics is weighing in on the issue of climate change, so I thought I would take the opportunity to try to dumb things down as much as possible. The basic science behind climate change is well-understood:
- The mean temperature is increasing, with significant variation superposed from place to place and year to year.
- This is caused largely by the anthropogenic increase in carbon dioxide and other greenhouse gases in the atmosphere, due to the very well-understood and uncontroversial physics of the carbon-dioxide molecule.
- Significant further increase would be societally bad for many people.
- Lowering our greenhouse-gas emissions can slow or halt the increasing temperatures.
At this coarse level, both the data and the theory underlying these conclusions are almost incontrovertible and ought to be uncontroversial, although each of these has been questioned by the
politically-motivated or ignorant deniers sceptics. Significant questions remain at a more detailed level, of course: what is the precise correlation between greenhouse-gas emissions and temperature? How much of the increase is due to emissions, and how much to other effects (e.g., solar irradiance variations)? Most importantly, what will the temperature increase be in the future, for various amounts of future carbon emission. These are important details, but the main point — the earth is warming due to our activities — is settled.
(Scientific American has an excellent rebuttal of the main points raised by the so-called sceptics.)
What I’ve never quite understood is the politics of climate change. It is an observational fact that climate change deniers tend to be from the (mainstream and libertarian) right. I can certainly understand political differences regarding the solution to climate change — a true free-marketeer wouldn’t want a carbon tax or even a cap-and-trade system (although, of course, either of these attempt to estimate the true cost of future emissions, rather than their purely short-term economic benefit). But why do politics trace our opinion of the science? The only explanation for this I can come up with is the right’s longstanding association with big business — in particular the oil business — which, even today, retains a vested interest in denying the simple truth of climate change.