The News & Observer has a Q&A with a climate expert — though I’m not sure why this UNC professor qualifies as such given that his degrees are in physics and nuclear science. In any case, I posed the following question last week, which appeared this weekend. Here’s the exchange:
Q: Simulations are not reality. Nor are they crystal balls. Wealth managers use the most sophisticated Monte Carlo techniques in attempting to forecast someone’s portfolio, say, twenty years from now. But these predictions are pretty vague, and lose resolution the further into the future the forecast goes. If they were less vague, we would all use sims to get rich and stay rich. But forecasting, particularly with the limited and imperfect data that are put into the best available forecasting technologies, is inherently unreliable. Why should we trust climate simulations any more than we do any other type, particularly when policymakers are looking to these sims for justification to radically restructure the energy sector?
A: You are certainly correct that simulations are not reality. They are at best simplifications of reality. But it is important to consider the KIND of simulation being done, and what you are asking of the simulation. For example, science has incredibly complex simulations that are so accurate we can launch a rocket from the earth and predict where it will land on Mars. We can drop a ball from a rooftop and predict almost the exact moment it will hit the ground, and at what speed. But we also have simulations of climate that are much less reliable. So some simulations are amazingly good and others not so good.
The climate change models used today are somewhere in the middle. They probably can’t be used to say exactly when the temperature will increase by 5 degrees, or which parts of the world will get more or less rain, etc. But they are accurate enough to say that there will be warming over the globe on average, that it will get worse over many centuries, that there will be places where the effects are good and others where they are bad, and that climate will become less predictable over time. That is in part, why most of the leaders in business and industry are interested in restructuring the energy sector for more reasons than climate change, focusing also on energy security, dwindling supplies of fossil fuels, and rising energy costs.
This is the kind of answer I expected. I’m pretty sure that Crawford-Brown is wrong, though, in claiming that climate sims are "in the middle" — particularly since he didn’t give us examples of the most inaccurate sims. Getting an object from earth to mars is more or less a narrow, deterministic (single causal chain) goal — where the corresponding simulations have only to calculate that. But climate is a highly complex system (with many subsystems) and many, many more input variables than Newtonian moon-landings. It’s not altogether clear that the information being put into these sims is all that accurate, either. In short: junk in, junk out. In any case, climate modeling may be leading us astray. (These models are susceptible to selection bias and politicization, too, but more on that later.) The most serious problem with these models is that – even if they were accurate – most are not able to factor in natural climate variability and model only greenhouse effects.
(Afterthought: More and more, we’re learning that the so-called climate "consensus" is made up scientists such as Crawford-Brown who are not experts in climatology at all, but rather came to environment activism sometime during their careers. Usually they have rather tenuous toeholds on their science backgrounds and have gotten into the global warming issue by way of fashionable academe. Basically, if the consensus is composed of folks who are not truly qualified to speak about such issues, how can we believe it?)