Roubini, a professor of economics at New York University’s Stern School of Business and the founder and chairman of Roubini Global Economics, is the author of MegaThreats: Ten Dangerous Trends That Imperil Our Future, and How to Survive Them, from which this essay is adapted Inflation is back, and it is rising sharply, especially over the past year, owing to a mix of both demand and supply factors. This rise in inflation may not be a short-term phenomenon: the Great Moderation of the past three decades may be over, and we may be entering a new era of Great Stagflationary...