Laws stay constant but the world changes

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Efforts by Stephen Schneider and Richard Moss to quantify uncertainty (Nature 418, 476–478; 2002) succeeded with the Intergovernmental Panel on Climate Change (IPCC) Working Group 1 climate modellers but failed with Working Group 3's emissions modellers. As a lead author on the IPCC's 2000 Special Report on Emissions Scenarios, I would like to elaborate on why this happened.

The first group of scientists know that the laws of physics operative today will be the same laws of physics operative in 2100. The second group, of economists and analysts, know with equal certainty that the geopolitical, socioeconomic and technological forces operative today are likely to be radically different in 2100.

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Gaffin, S. Laws stay constant but the world changes. Nature 419, 337 (2002) doi:10.1038/419337c

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