In what must rank as the mother of all unintended consequences, and in a finding certain to have effects on international policy, NASA scientists have found that a decrease in airborne sulfates–dirty smokestack particles caused by burning coal and regulated by the Clean Air Act since the 1970s to prevent acid rain and air pollution–may account for as much as 45% of Arctic warming. Dr. Drew Shindell of NASA’s Goddard Institute of Space Studies reports:
“Sulfates, which come primarily from the burning of coal and oil, scatter incoming solar radiation and have a net cooling effect on climate. Over the past three decades, the United States and European countries have passed a series of laws that have reduced sulfate emissions by 50%. While improving air quality and aiding public health, the result has been less atmospheric cooling from sulfates.”
Aerosols–sources range from dirty coal plants to hairspray–include both the cooling sulfates and the ultra-warming, sunlight-absorbing black soot. They appear and dissolve in the atmosphere much more quickly than greenhouse gases, which hang around for centuries, making them an effective target for short-term “geoengineering” type interventions.
[Images: Nasa Image of thunderstorms over Southern Brazil– researcher discovered that tiny airborne particles of pollution may modify developing thunderclouds; sulfate particles under an electron microscope.]