I don't usually write about environmental issues—in part because it's hard to care a lot about everything—but while editing this short piece for Mother Jones, a few things came to mind. My colleague Erik writes that economists are beginning to improve their cost-benefit analysis of various environmental resources. A forest, for instance, might be worth a couple million as lumber, but a billion dollars or more when you factor in: recreational use, quality-of-life benefits, and its benefits to the ecosystem—especially as a carbon sink. There are problems with this sort of valuation—can you really put a number on all of these factors?—but ideally, this should help environmentalists combat the things they'd like to combat; after all, serious liberals don't just want to preserve the environment because it's "pretty"; they want to preserve environmental resources because they're valuable—both now and for future generations.

Now from what I know about ecological economics, the proper way to determine whether a country's economic development is sustainable is whether there's a growth in wealth over time. Among other things that includes material goods, resource wealth, human capital, and natural capital. A nation could deplete some of these while increasing others, but in the aggregate, wealth should be growing, not shrinking. So a country can't just keep boosting its GDP while depleting its wealth base; otherwise you start to run into the situations seen in Jared Diamond's Collapse (which I haven't read). India, for instance, is growing like gangbusters, but environmental-types tell me that its natural resources are being quickly depleted, and that depletion isn't being compensated by increases in wealth elsewhere—building enough infrastructure, say, or investing enough in human education, etc. On the other hand, plenty of Indian policymakers are aware of this and trying to put the country on a more sustainable path.

So far, so good. Or bad. But now it doesn't seem like economists have really perfected their answers to the question about how much natural resources are really worth in wealth terms. Which would make it awfully hard to figure out exactly how sustainable or unsustainable are the paths on which certain countries—like China—are heading, no? At any rate, something else to learn more about, I guess.