In the middle of the Indian Ocean lies a unique region where pure air from the Southern Hemisphere meets air polluted by the billion inhabitants of the Indian subcontinent. The Ronald H. Brown docks in Capetown, South Africa, where the experiment began. The field cruise of Dickerson and his colleagues and their ongoing analysis of the data they collected are key parts of an extensive, international, multi-year field investigation of how natural and human forces are affecting climate changes in the atmosphere over the Indian Ocean.
Aerosols are tiny particles such as dust and soot.
In the atmosphere aerosols can reflect sun light back into space, thus reducing the amount of heat entering the Earth's atmosphere. Because increases in aerosols tend to cool the atmosphere, they are a countervailing force to the warming effects of increases in carbon dioxide and other greenhouse gases. Most scientists believe increasing levels of greenhouse gases in the atmosphere are driving the observed global warming trend. However, numerous computer models suggest that insufficient knowledge about aerosol cooling is one of the largest sources of uncertainty in predicting future climate change. Another significant finding was that most of the pollutants were the soots, sulfates and other products that come from burning wood, coal and other biomass.