How to Think About Global Warming

To think about the relationship between CO2 emissions and global warming, the most important step to take is to imagine that scientists had never invented climate models that presume to predict the future. In the absence of those models, what would you think about CO2 emissions? That's the question.

The reason to drop the climate models from consideration is that models of complex systems cannot predict the future in any area of science, so climate models should not be trusted until they are uniquely shown to be able to do that. So far, the models have not passed any serious test, and the excuse given is that, in the short term, unpredictable weather variations can mask predictable long-term climate trends. In the long-term, the argument goes, the models may be shown to be right after all. But get back to me in the long term because, for now, I have no reason at all to believe that the models are accurate (and neither do you).

Scientists who are infatuated with their own climate models seem to have a different view, namely, that the models should be trusted until those models are proven wrong. By definition, this cannot happen in the short term (because of unpredictable weather), so the models are protected from disconfirmation until decades go by. That's not a reasonable view because, in light of the general predictive utility of complex-system modeling, the odds are very high that the climate models are incorrect.

Once you take the models out of consideration, you realize that all of the alarmism and all of the "tipping point" hysteria come from believing that the models are true. Thus, if you remove the models from your own global warming thinking, you won't be an alarmist and you won't run around the world trying to convince everyone to take immediate and drastic action to reduce CO2 emissions before it is too late. However, just because you would not be a hysterical alarmist does not mean that you would not take the issue seriously. Jim Manzi at the NRO Corner seems to have his head on straight in this regard:

Yes, it’s true that it is very difficult to assign material historical damages to AGW, and global temperatures have been pretty much flat for a decade, and global climate models have not demonstrated that they can pass falsification trials for prediction of temperature change on a decadal scale. But on the other hand, no respectable scientist disputes that CO2 redirects long-wave radiation but not short-wave radiation. At some point, with high enough concentration in the atmosphere, it will create severe problems. There are trade-offs involved around how much wealth we sacrifice today in order to reduce by some hard-to-quantify amount the chance of large losses in the future.

That is a vastly more sensible way to think about the issue than the way our Nobel-Prize-winning, globe-trotting former vice president thinks about it. If you approach the issue in this manner, you won't be a global-warming alarmist or a head-in-the-sand flat-earther. And if everyone approached the issue in this manner, it would not be politicized, and scientists would not be injecting themselves into polarized politics. What a wonderful world that would be.