We know Earth’s temperature is on the rise, but how far is it going to go?
The short answer is, we don’t know. The long answer is, it depends on feedback loops. For example, how much will warming accelerate when we have less polar ice to reflect the sun?
An even longer answer—the one you might get from John Anda, President of Environmental Markets Network and former Vice Chairman at Morgan Stanley—is that it’s a question of probability distribution. In other words, we don’t know how much the Earth’s temperature is going to rise, but we have some idea of how likely the temperature is to rise by 2 degrees centrigrade, 3 degrees, 4 degrees, 5 degrees, etc.
The interesting thing about climate change is that those probabilities aren’t distributed in a normal bell curve—the kind that gave very few students As and very few students Fs, and a whole lot of students Bs and Cs, in your college 0-chem class. Instead, climate change has what’s called a fat-tail risk, a small but significant probability that the temperature will rise by 5-10 degrees Celsius, a change that would have catastrophic results for our climate.
If climate change were a grading curve for a class, it would look something like this: no As for anyone (because the temperature is already rising), quite a few Bs available for very hard-working, focused students (because we can probability limit temperature change to 2 degrees celsius, which we can probably adapt to, if we act quickly and aggressively), even more Cs for the less-focused students (a 3 degree rise in temperature), and somewhere between 10 and 30 percent Ds (4 degree rise in temperature), and about 10 percent Fs (more than 4 degree rise in temperature, which would be catastrophic). Only, instead of flunking O-Chem, the students who get Fs drop out of college, move back in with their parents, eventually end up in prison, and die alone.
With a probability distribution like that, it’s very important to avoid the small, but not insignificant, possibility of an F, because you just can’t afford one.
“The distribution of outcomes for climate is not normal, so we have to hedge that risk,” explained Mr. Anda at Carbon Trading Update, a talk on carbon markets and risk management, last week. “We don’t have the tools to hedge the risk of having something really bad happen to our climate – that’s in uninvented technologies. We really do need quantity limits on carbon.”
Mr. Anda, like his co-panelists, favors a cap and trade system that would limit greenhouse gas emissions enough to avoid catastrophic climate change, and use trading to reduce emissions in as cheaply and efficiently as possible.