PRAGUE – The Doha meeting continued 20 years of failed climate negotiations, since the original Earth Summit in Rio in 1992. There, countries pledged to cut greenhouse-gas emissions to 1990 levels by the year 2000; the OECD countries fell short by almost 9%. The Kyoto Protocol from 1998 has almost entirely failed. And the effort intended to save the world in Copenhagen in 2009 collapsed spectacularly.
So far, the world’s emissions have continued to rise – and at an accelerating pace – with emissions in 2011 about 50% higher than in 1990. The last 20 years of global climate negotiations has reduced that increase by only about half a percentage point.
Assuming, somewhat optimistically, that this reduction will be maintained throughout the century, it will reduce the temperature increase by about half of one-hundredth of a degree Celsius (about one-hundredth of a degree Fahrenheit) in 2100. Sea levels will rise about one millimeter (one-twentieth of an inch) less. Even in a hundred years, these changes will not be measurable.
The cost of achieving these underwhelming results has probably run about $20-30 billion a year – mostly foregone economic growth, owing to the forced use of more expensive energy. The benefits to humanity – measured in terms of marginally less flooding, an almost negligible reduction in heat waves, and so forth – total roughly $1 billion annually. Thus, in terms of bang for the buck, each dollar spent on climate policy has so far done about a nickel’s worth of good.