Geoengineering projects will jeopardize the Sahel

April 1, 2013. Jim Haywood of Center. Hadley UK Met Office and his colleagues calculated that the fine particles concentrated in the stratosphere could cause a catastrophic drought in the Sahel.

The scientists analyzed data from surveys conducted from 1900 to 2010 year, and found that three of the four driest summers in this region of Africa was preceded by sizable volcanic eruptions in the Northern Hemisphere, which raised huge clouds of aerosols in the upper atmosphere.

The violent eruptions in the past were associated with climate change: the explosion of the volcano Tambora (Indonesia) in 1815, followed by a "year without a summer" in Europe (1816 th), who were accompanied by widespread crop failure, famine and epidemics. A eruption volcano Pinatubo in 1991 led to the fact that climatologists later named "Mount Pinatubo effect" — a marked global cooling in the coming years.

But Mr. Haywood and his colleagues are not worried about the random nature of eruptions (that is, not that they are difficult to predict and can not be prevented), and the possibility of deliberate introduction of aerosols into the stratosphere to mitigate global warming.

Sahel savanna called the thousand kilometer strip south of the Sahara, stretching from Mauritania in the west to Eritrea on the Red Sea coast. Four driest season in this already not very humid region (called negative precipitation anomalies in Sahel) Occurred in 1913, 1972, 1983 and 1984. Three of them are preceded by volcanic eruptions Katmai in Alaska in 1912 and El Chichon in Mexico in 1982.

Continued drought 1970-1980-X claimed in the Sahel 250 thousand lives and created 10 million refugees. It was one of the largest humanitarian disasters in history. Offered a variety of explanations for this phenomenon, from overgrazing and natural climate variability to industrial emissions, but Mr Hevud and his colleagues believe that the volcanic activity is also strongly influenced by the temperature of water in the Atlantic, which is associated with drought Sahel.

This tentative conclusion. These connections are very difficult to prove quite convincingly. The jury is still in session.

The researchers conducted a simulation of global warming and found that (in the absence of any attempts geoengineering), only 11 of the 50 years (from 2020 to 2070 year) Once again see that the negative anomaly. If we still run the aerosols into the stratosphere in the Sahel comes protracted drought.

This effect might be able to draw the particles entering the stratosphere Southern hemisphere, which may lead to increased precipitation Sahel. But then it will be less rain in the north-east of Brazil …

The study is published in the journal Nature Climate Change.

Based on: Climate News Network
Source: Kompyulenta

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