Aerosols: bad news for developing countries
The effects of aerosols in the atmosphere will magnify the warming over several developing countries, shows a study by the Indian Ocean Experiment (INDOEX), an international field experiment which is being conducted by several countries including USA, Australia, France and Germany. "Aerosols have a heating effect on the atmosphere of the developing countries due to the presence of black carbon soot, a result of inefficient technologies used in these countries,' said A P Mitra, chairperson of National Physics Laboratory's Indian National Steering Committee of INDOEX. The study indicates that precipitation might change over tropical regions due to aerosols. Aerosols have both a warming and cooling effect on the climate, depending on their type, size and vertical location within the atmosphere. They are small airborne particles produced by natural phenomena as well as human activities, which account for 60 per cent of aerosols in the Earth's atmosphere. Cooling of the atmosphere results from these particles reflecting sunlight, whereas warming happens due to their absorbing heat. On a global average, however, aerosols are expected to have a cooling effect. Indirectly, aerosols influence climate by helping the formation of cloud droplets, making clouds brighter and more reflective. Aerosols can increase the amount of cloud cover, reflecting more sunlight or trapping more heat. This is also expected to reduce the rate of photosynthesis in plants.