Pollution in Asia is changing global climate patterns by altering the chemistry of the atmosphere, scientists say.
Research published in the Proceedings of the National Academy of Sciences this week (5 March) shows how increasing pollution creates more intense storms in the north Pacific region, affecting how global temperatures are regulated.
Renyi Zhang and colleagues from the Texas A&M University studied satellite cloud measurements from 1984 to 2005. They found that the number of a particular type of cloud ― deep convective clouds ― had increased by 20 to 50 per cent between 1994 and 2005, compared with the previous decade.
Deep convective clouds play a role in regulating the Earth's temperature. Their formation and duration and the amount of rainfall they produce can be influenced by aerosols ― particles suspended in the atmosphere. The burning of fossil fuels results in human-made aerosols such as sulphate and soot.
Zhang found that the activity of the Pacific storm track ― a weather phenomenon which plays a critical role in regulating the Earth's temperature ― is enhanced in the winter months, most likely due to the rise in deep convective clouds due to air pollution in Asia at this time.
According to the study, pollution tends to increase in Asia in winter as coal-burning is still the main source of heat and energy.
Zhang says that further air pollution from Asia, caused by rapid industrialisation and urbanisation, will continue to significantly influence storms over the Pacific, contributing to global warming.
Moreover, he warned that prevailing winds are able to carry the pollution northwards. "The intensified storm track may have more efficiently transferred heat and human-produced aerosols to the polar region, contributing to and exacerbating the observed Arctic warming," Zhang told SciDev.Net.
However, Ren Guoyu, an expert from the Beijing Climate Center under the China Meterological Administration, said there were still disputes in the scientific community over whether the Pacific storm track has changed. He said further research was needed.
Researchers have observed an increase in atmospheric aerosols over the past few decades, most likely caused by coal-burning in China and India. The National Statistics Bureau of China estimates that China burned nearly 2.4 billion tons of coal in 2006, accounting for 70 per cent of its energy consumption.