I decided to add my name to a petition by, as of this writing, 81 MIT faculty, calling on MIT to divest its endowment from fossil fuel companies. (My co-signatories include Noam Chomsky, so I guess there’s something we agree about!) There’s also a wider petition signed by nearly 3500 MIT students, faculty, and staff, mirroring similar petitions all over the world.

When the organizers asked me for a brief statement about why I signed, I sent them the following:

Signing this petition wasn’t an obvious choice for me, since I’m sensitive to the charge that divestment petitions are just meaningless sanctimony, a way for activists to feel morally pure without either making serious sacrifices or engaging the real complexities of an issue. In the end, though, that kind of meta-level judgment can’t absolve us of the need to consider each petition on its merits: if we think of a previous crisis for civilization (say, in the late 1930s), then it seems obvious that even symbolic divestment gestures were better than nothing. What made up my mind was reading the arguments pro and con, and seeing that the organizers of this petition had a clear-eyed understanding of what they were trying to accomplish and why: they know that divestment can’t directly drive down oil companies’ stock prices, but it can powerfully signal to the world a scientific consensus that, if global catastrophe is to be averted, most of the known fossil-fuel reserves need to be left in the ground, and that current valuations of oil, gas, and coal companies fail to reflect that reality.

For some recent prognoses of the climate situation, see (for example) this or this from Vox. My own sense is that the threat has been systematically understated even by environmentalists, because of the human impulse to shoehorn all news into a hopeful narrative (“but there’s still time! if we just buy locally-grown produce, everything can be OK!”). Logically, there’s an obvious tension between the statements:

(a) there was already an urgent need to act decades ago, and

(b) having failed to act then, we can still feasibly avert a disaster now.

And indeed, (b) appears false to me. We’re probably well into the era where, regardless of what we do or don’t do, some of us will live to see a climate dramatically different from the one in which human civilization developed for the past 10,000 years, at least as different as the last Ice Ages were.

And yet that fact still doesn’t relieve us of moral responsibility. We can buy more time to prepare, hoping for technological advances in the interim; we can try to bend the curve of CO 2 concentration away from the worst futures and toward the merely terrible ones. Alas, even those steps will require political will that’s unprecedented outside of major wars. For the capitalist free market (which I’m a big fan of) to work its magic, actual costs first need to get reflected in prices—which probably means massively taxing fossil fuels, to the point where it’s generally cheaper to leave them in the ground and switch to alternatives. (Lest anyone call me a doctrinaire treehugger, I also support way less regulation of the nuclear industry, to drive down the cost of building the hundreds of new nuclear plants that we’ll probably need.)

These realities have a counterintuitive practical implication that I wish both sides understood better. Namely, if you share my desperation and terror about this crisis, the urgent desire to do something, then limiting your personal carbon footprint should be very far from your main concern. Like, it’s great if you can bike to work, and you should keep it up (fresh air and exercise and all). But I’d say the anti-environmentalists are right that such voluntary steps are luxuries of the privileged, and will accordingly never add up to a hill of beans. Let me go further: even to conceptualize this problem in terms of personal virtue and blame seems to me like a tragic mistake, one on which the environmentalists and their opponents colluded. Given the choice, I’d much rather that the readers of this blog flew to all the faraway conferences they wanted, drove gas-guzzling minivans, ate steaks every night, and had ten kids, but then also took some steps that made serious political action to leave most remaining fossil fuels in the ground even ε more likely, ε closer to the middle of our Overton window. I signed the MIT divestment petition because it seemed to me like such a step, admittedly with an emphasis on the ε.