Atmospheric brown clouds: regional assessment report with focus on Asia: summary

Source: UNEP
"Cities from Beijing to New Delhi are getting darker, glaciers in ranges like the Himalayas are melting faster and weather systems becoming more extreme, in part, due to the combined effects of man-made Atmospheric Brown Clouds (ABCs) and greenhouse gases in the atmosphere. These are among the conclusions of scientists studying a more than three km-thick layer of soot and other manmade particles that stretches from the Arabian Peninsula to China and the western Pacific Ocean. Today the team, drawn from research centres in Asia including China and India, Europe and the United States, announced their latest and most detailed assessment of the phenomenon. The brown clouds, the result of burning of fossil fuels and biomass, are in some cases and regions aggravating the impacts of greenhouse gas-induced climate change, says the report. This is because ABCs lead to the formation of particles like black carbon and soot that absorb sunlight and heat the air; and gases such as ozone which enhance the greenhouse effect of CO2. Globally however brown clouds may be countering or ‘masking’ the warming impacts of climate change by between 20 and up to 80 per cent the researchers suggest."