Rainfall Changes Linked To Human Activity
Greenhouse-gas emissions have made the Northern Hemisphere wetter &mdash and climate models appear to have underestimated the changes. Research from the Canadian Centre for Climate Modelling and Analysis, published in Nature, finds that human activity has made the weather wetter in a large slice of the Northern Hemisphere, while making the regions just south of the Equator wetter, and those just north of it drier. Agriculture and human health have already been affected. The proof that human activity has altered rainfall patterns was found in comparisons of observed changes with climate models. Specifically with observed rainfall during the twentieth century compared to rainfall predicted by 14 climate models. In the zone between 40 and 70 °N, which includes much of North America and most of Europe, rainfall increased by 62 millimeters per century between 1925 and 1999. The researchers estimate that between 50 and 85% of this increase can be attributed to human activity.