Climate Change

Occasionally, knowing or learning my occupation, someone will ask what I think about global warming. I always forget, and then only slowly realize, that generally the other person has already made up his/her mind, and is only waiting for me to agree.

Climate is complex—hard to see the forest for the trees. In The Climate Fix, Roger Pielke Jr. provides a good overview of the forest. The book begins with the opening rounds of the public global warming debate, which was kicked off in June of 1988 by a Senator Gore hearing. The memory of that hearing escapes me. But I do recall that later that year was when I first started meeting folks who had already made up their minds.

The scientific debate has never been about predictions. It is about communicating predictability. Recently the debate has been depicted as weather forecasters vs. climate scientists. But weather forecasters are equally as inept as climate scientists at communicating ambiguity (or the lack of it). When I was a student at Penn State, there was a senior forecaster notorious for overstating the prospect of getting a foot of snow. The exaggerated forecast would be broadcast in the evening. The following morning a neophyte would squint into the sunshine while fielding snide telephone queries, Where's the snow? The problem exists in the other direction as well. It'll never happen verifies as a wise and gutsy forecast every time, except for when it does happen.

In the sidebar is a link to Roger Pielke Sr.'s Climate Science blog. I've enjoyed reading the guest posts there by Hendrik Tennekes. Professor Tennekes' course on turbulence was a valuable introduction to a different way of thinking. Exam questions would instruct you to Estimate ... rather than Calculate ... Some students persisted in calculating precise answers. I think maybe they became climate modelers.

I ran across this 1988 article (cookie required) by Hendrik Tennekes discussing predictability. In the two decades since that article was published there have been tremendous advances in understanding uncertainty in weather forecasts. Ensemble forecasts (e.g. the GEFS) try to capture the full range of possibilities, i.e. everything that could go wrong. Sometimes the answer is continued uncertainty, even when the event is only a short time away. Other times the ensembles reveal surprising confidence in the extended outlook. Unfortunately, little of this information about ambiguity (or lack of it) gets communicated to the general public. Weather forecasters criticizing climate scientists for not faithfully communicating predictability is like the pot calling the kettle black. Still, the criticism is warranted. I don't think uncertainty confuses the general public. I think the reluctance to recognize unresolvable uncertainty is what is confusing. Most people can understand that uncertainty about climate change is a cause for concern, not an excuse to be complacent.