Scientists warn geoengineering may disrupt rainfall

LONDON Wed Jun 6, 2012 9:38am EDT

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LONDON (Reuters) - Large-scale engineering projects aimed at fighting global warming could radically reduce rainfall in Europe and North America, a team of scientists from four European countries have warned.

Geoengineering projects are controversial, even though they are largely theoretical at this point. They range from mimicking the effects of large volcanic eruptions by releasing sulphur dioxide into the atmosphere, to deploying giant mirrors in space to deflect the sun's rays.

Proponents say they could be a rapid response to rising global temperatures but environmentalists argue they are a distraction from the need to reduce man-made carbon emissions.

Critics also point to a lack of solid research into unintended consequences and the absence of any international governance structure for such projects, whose effects could transcend national borders.

A small geoengineering experiment in the UK was recently abandoned due to a dispute over attempts by some of the team involved to patent the technology.

In this new study scientists from Germany, Norway, France and the UK used four different computer models that mimic the earth's climate to see how they responded to increased levels of carbon dioxide coupled with reduced radiation from the sun.

Their scenario assumed a world with four times the carbon dioxide concentration of the preindustrial world, which lead author Hauke Schmidt says is at the upper end, but in the range of what is considered possible at the end of this century.

They found that global rainfall was reduced by about 5 percent on average using all four models.

"Climate engineering cannot be seen as a substitute for a policy pathway of mitigating climate change through the reduction of greenhouse gas emissions," they said in the study, published in Earth System Dynamics, an open access journal of the European Geosciences Union.

Under the scenario studied, rainfall diminished by about 15 percent, or about 100 millimeters per year, compared to pre-industrial levels, in large areas of North America and northern Eurasia.

Over central South America, all the models showed a decrease in rainfall that reached more than 20 percent in parts of the Amazon region.

(Editing by Mark Heinrich)

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Comments (4)
MikeBee wrote:
I have to say I am very skeptical of any form of geoengineering based on the fact that it is man’s CO2 pollution (unintended geoengineering) that got us into this mess. The planet was doing fine without our input, and it follows that the solution is for there to be less human input, not more.
Kind of like the financial meltdown: you shouldn’t turn to those who created the (financial or ecological)problem to solve the problem, especially if they are suffering from conflicts of interest.

Jun 06, 2012 7:36pm EDT  --  Report as abuse
I also have to wonder about the subject of chem-trails. I know it may sound crazy to most but there are scientists who are finding increased levels of barium and aluminum in remote places. No one can say this is impossible because this practice of aerial spraying was done in China to make rain fall before it got over the Olympic games. Not to mention the patent for HARRP says it can be used to affect rainfall in certain areas. I think like everything else, there is a lot more going on than we are being told for what ever reason. I just wish we could get to the truth for once. Mirrors in space and mimicing volcanoes may be far fetched but I would bet they are trying a few things. I have to agree with MikeBee , they should fix the cause not add more problems. All they have to do is see the long term profit in it.

Jun 06, 2012 11:10pm EDT  --  Report as abuse
AZWarrior wrote:
Evolution is about adaption. The earth will continue warming during this cycle and we as a species had better learn to adapt. Spending all our time and effort to stop this warming is losing battle. We can intelligently reduce our contributions to the warming, but the natural world will still cycle warmer. The sun’s current warming cycle will occur regardless of anything mankind does. We must slow the effect where it is practical, and prepare for the results of climatic change by adapting. Some examples of adaptation could include moving population centers fruther from low lying coastlines, construction of waterwalls and barriers to preserve land from ocean encroachment, and other infrastructure adaptations. A major effort to bring fussion power on line to support air conditioning of large number of buildings and to replace fossil fuel power plants. Gene studies to explore speeding up the adaptation process of food grains and food animals to make them more drought and UV tolerant. Of course, we could just argue and pout like now and go extinct like the other 99.5% of all life that has ever existed on earth. That too is how evolution works.

Jun 07, 2012 5:11pm EDT  --  Report as abuse
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