Effects of Global Warming ‘Masked’ by Asia Pollution, Study Says

A new study says rising sulfur emissions from the growth of Asian industry triggered a cooling effect that partially offset the effects of global warming for a decade. While carbon dioxide emissions increased by nearly a third from 1998 to 2008, global surface temperatures did not rise sharply during that period. A key reason, researchers said, is that increased sulfur emissions — particularly from coal combustion in Asia, which grew by more than 100 percent during the decade — allowed the formation of aerosols that reflect the sun’s heat back into space, cooling the surface of the Earth. Such effects have long been recognized by scientists studying volcanic eruptions, which in the past have caused cooling and significant crop failures. “Anthropogenic activities that warm and cool the planet largely cancel after 1998, which allows natural variables to play a more significant role,” according to the paper, published in the journal Proceedings of the National Academy of Sciences. That natural cooling effect may abate, however, when nations impose stricter emissions standards, possibly releasing a rapid, pent-up climate change, according to the researchers.