As recently as the late 1970’s air emissions in Europe and the USA were terribly high. For instance, in 1978 sulfur dioxide (SO2)-emissions in Europe stood at 70 million tons (Figure 1), almost three times higher than current Chinese emissions. Not only were emissions terribly high, but any impartial observer of the future seen from the perspective of 1978, basing his views on recent trends in European SO2-emissions from 1945-1978, would have had to admit that realistically, emissions would continue to grow. Only the bravest would have suggested that come 25 years later emissions of SO2 in Europe would stand.
