Our health care system and our climate system would seem to have little in common. Except this: over the last decade or so the behavior of both systems has completely befuddled the experts.
Since the early 2000s, the rate of growth of health care spending has slowed dramatically. Yet there is no model that predicted that outcome or that can explain why it has happened. Similarly, for the past 16 years there has been no increase in global warmingdespite a 25 percent increase in human contribution to atmospheric carbon dioxide. There is no computer model that can explain that either.