Focus on uncertainty and risk in climate change

Unfortunately Alex Epstein, a blogger at Forbes, takes the wrong perspective–an underlying premise that we need absolute certainty that climate change is occurring before we should act. (And equally unfortunately, environmentalist argue that catastrophic climate change is occurring with absolute certainty to defend policy initiatives.)

The correct perspective is to ask “what are the relative risks and consequences posed by potential climate change?” Can we say with absolute certainty that GCC is not and will not occur? No, we have strong evidence that warming has occurred (although the rate can be disputed) and that various local climates have measurably changed (e.g., glaciers receding). As an analogy, would anyone argue that we shouldn’t take measures to reduce forest fire risks to communities even if fires aren’t burning nearby? We know that such fires are a strong risk, and we ask what actions are sufficient to reduce the risks while still achieving other objectives. We should be asking the same questions regarding responses to potential climate change.

Steve Moss and I wrote about this perspective in 1999 in Chapter 2 of this report. (Note that we did not coauthor the other chapters. Chapter 3 about the economic consequences of using carbon taxes to replace other tax revenues in particular is simply wrong.) Economists have evolved methodologies beyond the simple approach we presented there, such as robust decision making (RDM)real options analysis and “fat-tailed” uncertainty benefit-cost analysis. We face a great deal of uncertainty in many dimensions. We need to conduct more complete analyses that assess the potential costs and benefits under uncertainty–i.e., measure the risk of relative actions and non actions.

Simply having a battle over which scientists are correct is fruitless and distracts us from the real question at hand. Let’s agree that a large plurality of scientists have posed a plausible case for human-induced climate change, even if there are doubts about the potential magnitude and consequences. Then we can move on to what are the range of potential consequences and the justification for various responses.


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