Brown haze a potential threat to climate. (Property/Casualty: Loss/Risk Management Notes).

A brown haze of pollution enveloping many regions of Asia may become a global problem affecting rainfall, agriculture and the health of hundreds of thousands of people, according to international scientists.

Working for the United Nations Environment Program, scientists are basing the prediction on data from the Indian Ocean Experiment, which accumulated its findings from observations made from ships, aircraft and satellites. The haze, an aftereffect of fossil-fuel burning, forest-fire smoke and emissions from stoves burning wood and animal waste, has been hanging over Asia and is now moving to other areas of the globe.

This area is the most densely populated area of the world that has a monsoon climate, high pollution level, water shortages, and farming activity. The brown haze, according to the United Nations Environment Program, can impact all of these aspects by reducing the solar radiation reaching the Earth's surface, limiting the amount of rain produced, and increasing the frequency and strength of the thermal inversion that traps pollutants in the atmosphere. The brown haze may be changing the pattern of the winter monsoon in this region, reducing the amount of rain falling on northwestern Asia and increasing it in the eastern half of Asia.

The report by the United Nations Environment Program on brown haze stresses that the scientific community is at the nascent stages of understanding how regional climate changes influence the global climate.