XIAN, CHINA — The Asian summer monsoon typically brings about a lot of rainfall, but scientists have found that the rate of precipitation has actually been declining over the past eight decades, according to a study published in Geophysical Research Letters.<br /><br />According to National Geographic, the summer monsoon usually takes place between the months of April to September.<br /><br />New research from the journal Geophysical Research Letters says that rainfall during the Asian summer monsoon has been found to be decreasing in strength over the past 80 years.<br /><br />Human-made atmospheric pollutants such as sulfate aerosol emissions could be contributing to the reduction, according to a University of Arizona news release.<br /><br />Using climate models, scientists found that as the amount of pollutants in the atmosphere increases, the rate of monsoon rain tends to decline.<br /><br />The researchers also looked at tree-ring data from north China over the past 450 years to determine precipitation rates over the decades. This is because trees tend to grow thicker rings during wetter years.<br /><br />Factors such as solar variability and volcanic eruptions are also believed to impact the strength of the Asian summer monsoon.<br /><br />As rainfall from the summer monsoon has been declining, this has had an impact on water availability, ecosystems and agriculture across the globe.
