Sulfur dioxide emissions in Asia in the period 1985–1997

A consistent set of SO2 emission trends has been developed for Asian countries for the time period 1985–1997. The trend is based on extrapolation of a detailed 1990 inventory, which was constructed as part of the World Bankʹs RAINS-ASIA project, using IEA energy-use data. The trend shows Asian SO2 emissions growing from 33.7 Tg in 1990 to 39.2 Tg in 1997. Estimates interpolated from the RAINS-ASIA computer model suggest a value for 1997 of 46.4 Tg, assuming no major changes in emission abatement policies after 1990. The reduction in the 1997 value, by some 16%, is primarily due to regulatory requirements and other trends toward lower sulfur content of oil products and coal. A slowdown in the growth of emissions in China – due to a reduction in economic growth, the mining of higher-quality coals, enhanced environmental awareness, and a reduction in industrial coal use – has been instrumental in arresting the growth of Asian emissions. Most of the positive developments have occurred in East Asia, and high-emission growth rates persist in Southeast Asia and the Indian subcontinent. The outlook for the future is that Asian SO2 emissions may well peak in the region of 40–45 Tg by the year 2020 or earlier, in contrast to previous predictions of 2020 emissions as high as 80–110 Tg. The trends developed in this paper are good news for the local and regional environment, particularly in East Asia. However, they also signify lower-than-anticipated concentrations of sulfate aerosol over the Asian continent, with the resulting possibility of greater-than-anticipated regional and global warming.