Asia's brown clouds 'warm planet'

02/08/2007

Clouds of pollution over the Indian Ocean appear to cause as much warming as greenhouse gases released by human activity a study has suggested. US researchers used unmanned aircraft to measure the effects of the brown clouds on the surrounding area. Writing in Nature they said the tiny particles increased the solar heating of the lower atmosphere by about 50%. The warming could be enough to explain the retreat of glaciers in the Himalayas the scientists proposed. The clouds contain a mixture of light absorbing aerosols and light scattering aerosols which cause the atmosphere to warm and the surface of the Earth to cool. The main sources of the pollutants came from wood burning and fossil fuels the team added.