Geoengineering is the deliberate large-scale engineering and manipulation of the environment to combat or counteract anthropogenic changes in atmospheric chemistry. It has long been touted as a way to counter the catastrophic effects of global warming, but has been considered dangerous by some as it interferes with the world’s delicate ecosystems. This week, such fears gained the support of scientists from four European countries who believe that large scale engineering projects could radically reduce rainfall in Europe and North America.
Many of the most controversial projects remain little more than untested theories, which range from generating more clouds to reflect sunlight to deploying large mirrors into the atmosphere to create a solar shield. While they could work, they are deemed to be ridiculously expensive, particularly when one considers that one of the most effective solutions to counter climate change would be to reduce our dependency on fossil fuels.
The unknown side effects of geoengineering are also a cause for concern and as such, a UK-based experiment was recently cancelled due to disputes within the team. Now a group of scientists from Germany, Norway, France and the UK have used four different computer models to mimic the Earth’s climate to see how it responds to increased levels of carbon dioxide coupled with reduced radiation from the sun. Their scenario aims to duplicate a world that has 4x the carbon dioxide concentration of the pre-industrial world, which is believed to be a possibility by the end of this century. In their simulations, they discovered that global rainfall was reduced by about 5% on average using all four models.
Overall, rainfall decreased by 15%, or about 100 millimeters per year, compared to pre-industrial levels, in large areas of North America and northern Eurasia. Over central South America, the models showed a decrease in rainfall that reached more than 20% in certain parts of the Amazon region.
“Climate engineering cannot be seen as a substitute for a policy pathway of mitigating climate change through the reduction of greenhouse gas emissions,” the team wrote in their report which is published in Earth System Dynamics, an open access journal of the European Geosciences Union.
The news may well come as a blow to Bill Gates who has openly endorsed geoengineering projects over the past few years.
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