THE LIST OF REASONS for not acting on climate change is long and ever-shifting. First it was “there’s no problem”; then it was “the problem’s so large there’s no hope.” There’s “China burns stuff too,” and “it would hurt the economy,” and, of course, “it would hurt the economy.” The excuses are getting tired, though. Post Sandy (which hurt the economy to the tune of $100 billion) and the drought ($150 billion), 74 percent of Americans have decided they’re very concerned about climate change and want something to happen.

But still, there’s one reason that never goes away, one evergreen excuse not to act: “you’re a hypocrite.” I’ve heard it ten thousand times myself — how can you complain about climate change and drive a car/have a house/turn on a light/raise a child? This past fall, as I headed across the country on a bus tour to push for divestment from fossil fuels, local newspapers covered each stop. I could predict, with great confidence, what the first online comment from a reader following each account would be: “Do these morons not know that their bus takes gasoline?” In fact, our bus took biodiesel — as we headed down the East Coast, one job was watching the web app that showed the nearest station pumping the good stuff. But it didn’t matter, because the next comment would be: “Don’t these morons know that the plastic fittings on their bus, and the tires, and the seats are all made from fossil fuels?”

Actually, I do know — even a moron like me. I’m fully aware that we’re embedded in the world that fossil fuel has made, that from the moment I wake up, almost every action I take somehow burns coal and gas and oil. I’ve done my best, at my house, to curtail it: we’ve got solar electricity, and solar hot water, and my new car runs on electricity — I can plug it into the roof and thus into the sun. But I try not to confuse myself into thinking that’s helping all that much: it took energy to make the car, and to make everything else that streams into my life. I’m still using far more than any responsible share of the world’s vital stuff.

And, in a sense, that’s the point. If those of us who are trying really hard are still fully enmeshed in the fossil fuel system, it makes it even clearer that what needs to change are not individuals but precisely that system. We simply can’t move fast enough, one by one, to make any real difference in how the atmosphere comes out. Here’s the math, obviously imprecise: maybe 10 percent of the population cares enough to make strenuous efforts to change — maybe 15 percent. If they all do all they can, in their homes and offices and so forth, then, well . . . nothing much shifts. The trajectory of our climate horror stays about the same.

But if 10 percent of people, once they’ve changed the light bulbs, work all-out to change the system? That’s enough. That’s more than enough. It would be enough to match the power of the fossil fuel industry, enough to convince our legislators to put a price on carbon. At which point none of us would be required to be saints. We could all be morons, as long as we paid attention to, say, the price of gas and the balance in our checking accounts. Which even dummies like me can manage.

I think more and more people are coming to realize this essential truth. Ten years ago, half the people calling out hypocrites like me were doing it from the left, demanding that we do better. I hear much less of that now, mostly, I think, because everyone who’s pursued those changes in good faith has come to realize both their importance and their limitations. Now I hear it mostly from people who have no intention of changing but are starting to feel some psychic tension. They feel a little guilty, and so they dump their guilt on Al Gore because he has two houses. Or they find even lamer targets.

For instance, as college presidents begin to feel the heat about divestment, I’ve heard from several who say, privately, “I’d be more inclined to listen to kids if they didn’t show up at college with cars.” Which in one sense is fair enough. But in another sense it’s avoidance at its most extreme. Young people are asking college presidents to stand up to oil companies. (And the ones doing the loudest asking are often the most painfully idealistic, not to mention the hardest on themselves.) If as a college president you do stand up to oil companies, then you stand some chance of changing the outcome of the debate, of weakening the industry that has poured billions into climate denial and lobbying against science. The action you’re demanding of your students — less driving — can’t rationally be expected to change the outcome. The action they’re demanding of you has at least some chance. That makes you immoral, not them.

Yes, they should definitely take the train to school instead of drive. But unless you’re the president of Hogwarts, there’s a pretty good chance there’s no train that goes there. Your students, in other words, by advocating divestment, have gotten way closer to the heart of the problem than you have. They’ve taken the lessons they’ve learned in physics class and political science and sociology and economics and put them to good use. And you — because it would be uncomfortable to act, because you don’t want to get crosswise with the board of trustees — have summoned a basically bogus response. If you’re a college president making the argument that you won’t act until your students stop driving cars, then clearly you’ve failed morally, but you’ve also failed intellectually. Even if you just built an energy-efficient fine arts center, and installed a bike path, and dedicated an acre of land to a college garden, you’ve failed. Even if you drive a Prius, you’ve failed.

Maybe especially if you drive a Prius. Because there’s a certain sense in which Prius-driving can become an out, an excuse for inaction, the twenty-first-century equivalent of “I have a lot of black friends.” It’s nice to walk/drive the talk; it’s much smarter than driving a semi-military vehicle to get your groceries. But it’s become utterly clear that doing the right thing in your personal life, or even on your campus, isn’t going to get the job done in time; and it may be providing you with sufficient psychic comfort that you don’t feel the need to do the hard things it will take to get the job done. It’s in our role as citizens — of campuses, of nations, of the planet — that we’re going to have to solve this problem. We each have our jobs, and none of them is easy.