Wednesday, June 6, 2012

Geoengineering could disrupt rainfall patterns

European Geosciences Union: A geoengineering solution to climate change could lead to significant rainfall reduction in Europe and North America, a team of European scientists concludes. The researchers studied how models of the Earth in a warm, CO2-rich world respond to an artificial reduction in the amount of sunlight reaching the planet’s surface. The study is published today in Earth System Dynamics, an Open Access journal of the European Geosciences Union (EGU).

Tackling climate change by reducing the solar radiation reaching our planet using climate engineering, known also as geoengineering, could result in undesirable effects for the Earth and humankind. In particular, the work by the team of German, Norwegian, French, and UK scientists shows that disruption of global and regional rainfall patterns is likely in a geoengineered climate. “Climate engineering cannot be seen as a substitute for a policy pathway of mitigating climate change through the reduction of greenhouse gas emissions,” they conclude in the paper.

Geoengineering techniques to reduce the amount of solar radiation reaching the Earth’s surface range from mimicking the effects of large volcanic eruptions by releasing sulphur dioxide into the atmosphere to deploying giant mirrors in space. Scientists have proposed these sunlight-reflecting solutions as last-ditch attempts to halt global warming. But what would such an engineered climate be like?
...Under the scenario studied, rainfall strongly decreases – by about 15 percent (some 100 millimetres of rain per year) of preindustrial precipitation values – in large areas of North America and northern Eurasia. Over central South America, all models show a decrease in rainfall that reaches more than 20 percent in parts of the Amazon region. Other tropical regions see similar changes, both negative and positive. Overall, global rainfall is reduced by about five percent on average in all four models studied....

Rainfall in Beijing, shot by Shizhao, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

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