While the effects of power plant emissions, vehicle exhaust and other manmade aerosols on air quality and public health are well-known, their impact on the climate is not completely understood. Scientists have shown that aerosols can lower surface temperatures either directly, by reflecting sunlight skyward, or indirectly, by increasing the reflectivity of clouds, but until…

Big hopes are riding on the 2015 United Nations climate change conference planned for Nov. 30-Dec. 11 in Paris, where more than 190 nations will strive to hammer out an international agreement aimed at lowering global temperatures through significant reductions in human-made greenhouse gas (GHG) emissions. But the meeting, known as COP21, or the 21st Session…