If we could get a whole new continent---equal to twice the size of the continental United States---of vegetation by spending, say, $100 billion, would that be a good deal? How would we go about answering that? Well, we might start by noting that the total value of crops raised in the U.S. in 2016 was about $143.4 billion. That's for one year. And it's from just about 18 percent of all U.S. land. But we're talking about adding a continent of vegetation double the size of the United … [Read more...]