If the global price of oil had jumped by 50%, there is little doubt that economic commentators would be calling it a disaster for world growth. The price has in fact fallen by more than 50% since last June, but this ray of good news has not yet pierced the prevailing gloom of economic commentary. The impact ought to be perceptible: It represents an annual transfer of around 2% of world output from oil producers to oil consumers.
Part of the problem is that economists, like many other commentators, find a gloomy story more interesting than a happy one. Also, every silver lining is part of a dark cloud, and economists will always find an "on the other hand" counterargument. With the oil price fall, there are winners and losers. And in any case, a sharp change in prices requires adjustments and adaptations, which often cause problems. This unexpectedly dramatic change is also a reminder that the future is uncertain, which encourages forecasters to hedge their bets and investors to be cautious.