This is an excerpt from Maggie Koerth-Baker’s new book, Before the Lights Go Out: Conquering the Energy Crisis Before It Conquers Us. We’ve also got an interview with the author, in which she talks about finding common ground with climate deniers, the value of individual action in fixing a broken energy system, and the price of gas.

We could theoretically put climate change on pause right now — lock in atmospheric accumulation of carbon dioxide at its current level and stop the process from getting worse. Efficiency and conservation could do that. But you wouldn’t like the outcome very much, says Stephen Pacala, the director of the Carbon Mitigation Initiative at Princeton University. To solve the problem that way, we’d have to adopt a very strict and meager rationing of greenhouse gas emissions — just one ton of emissions per year, per person.

A ton sounds like a lot, but in this case, it’s not. The resulting budget would look less like a prudent belt-tightening and more like the work of Ebenezer Scrooge, pre-Christmas. One ton of greenhouse gas emissions buys a year’s worth of heat for one average home in the United States, Pacala says. That’s not including electricity, clothes, food, or transportation. Do you travel a lot for business? Maybe you could spend your one ton of emissions on airline flights instead. On that yearly budget, you can afford to fly 10 thousand miles in coach. Of course, again, that leaves you with no food to eat, no clothes to wear, and no house to come home to.

So, there’s saving the future, and then there’s actually being able to enjoy the future we saved. If you want the latter, it’s clear that simply reducing energy demand won’t be enough. In fact, no one change will be enough. Pacala made this point about efficiency and conservation not because he’s a killjoy or because he doesn’t think those efforts are worthwhile. He made it because he’s convinced that no single change can solve our energy problems.