We've talked, many times, about the morality of spending hundreds of billions (yes, billions) of dollars on global warming when other investments would bring far, far more benefit to the world's poor. This piece from The Wall Street Journal is one of the best I have read on the subject. For example, we have made some progress: Most of the original Millennium Development Goals will have been met or nearly so by 2015. Since 2000, for example, the number of people living in extreme poverty and hunger around the world will have been cut in half—an astonishing achievement. So, how do we make progress for the rest of the developing world? The numbers produced by this exercise are eye-catching. Every dollar spent to alleviate malnutrition can do $59 of good; on malaria, $35; on HIV, $11. As for fashionable goals such as programs intended to limit global warming to less than two degrees Celsius in the foreseeable future: just 2 cents of benefit for each dollar spent. P...