As reported in Climate Change to the Year 2000: A Survey of Expert Opinion, a broad spectrum of subjective probabilities was distilled into five scenarios which describe possible global climate changes to the year 2000. Reported in the two volumes of the second phase report are estimates of how crop yields would respond to these climate changes if there were no changes in agricultural technology. The most likely climate change, a slight global warming with a 'probability' of 0.30, was found to have negligible effects on 15 'key' crops. The more appreciable effects of the other climate changes differed from crop to crop in direction and magnitude; Canadian and Soviet wheat yields registered the largest responses. The potential crop-yield effects of technological change are judged to be several fold larger than the effects of the posited climate changes.