Global warming has paused. Greenhouse-gas emissions are soaring, but global mean temperature has been flat for more than a decade.
The Economist opines:
The mismatch might mean there has been a temporary lag between more carbon dioxide and higher temperatures. Or it might be that the 1990s, when temperatures were rising fast, was the anomalous period. Or it may be that the climate is responding to higher concentrations of carbon dioxide in ways that had not been properly understood before.
Where does this leave the global warming debate?
- There is global warming – about 1°C over the last century. Yet, it has now leveled off. Whether temporarily or not, nobody can say.
- The causes of global warming now seem even more murky. This new finding suggests that it is very difficult to tell what the causes are, particularly how much of it is due to human activity.
- The future is a lot more unclear. Predictions about the future of global warming just got a whole lot less credible.
- The effects of global warming have always been murky. Nobody really knows whether global warming will have good, bad, or both good and bad effects for humanity.
- Current policies are having only a minimal effect on reducing CO2 emissions. (Zero effect in most of the world, Europe being the main exception.) But, in light of this new evidence, that may be good enough.
- Stricter policies are not likely. The global governance of CO2 may be limited, but they are about as much as can be expected, particularly in a period of austerity.
- The costs of any greater efforts at limiting CO2 emissions may not be worth it.
(Earlier comment here.)