If the countries of the world reduced their greenhouse gas emissions today enough to keep the world from warming more than 2 degrees Celsius, when would they be able to tell that these efforts had succeeded?
That's the basic question posed in a paper released yesterday in the journal Proceedings of the National Academy of Sciences.
The answer: about 25 to 30 years, at least where global temperatures are concerned. On a regional level, it may take even longer to see the changes, the paper states.
From a scientific perspective, Tebaldi said it was interesting to try to separate the signal of man-made climate change, and efforts to curb it, from the noise of this variability.