Dimming the sun may be a solution to climate change, scientists claim
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Solar geoengineering, a technique where aerosol particles are injected into the stratosphere to reflect away a little inbound sunlight, is being hyped as a potentially easy solution to climate change.
Scholars from countries including Bangladesh, Brazil, China, Ethiopia, India, Jamaica and Thailand have written a paper in the Nature stating that the technique could particularly benefit the developing countries most vulnerable to global warming.
If successful, solar geoengineering could theoretically slow, stop or even reverse the rise in global temperatures within one or two years they said. However, they also concede that the process is controversial as scientists are currently unsure about the effect it might have on the climate.
“Developing countries must lead on solar geo-engineering research,” they added.
Although other solutions to climate change have been suggested, such as sucking carbon dioxide out of the atmosphere, this could take decades to have an impact.
The technique mimics volcanic eruptions that can cool the Earth by masking the sun with a veil of ash. A decade of modelling research indicates that solar geoengineering might reduce many of the worst effects of climate change if deployed in moderation.
For example, injecting five megatonnes of sulfur dioxide into the stratosphere — about one quarter of that released by Mount Pinatubo’s eruption in 1991 — each year could keep warming below 2°C.
Studies have also found that solar geoengineering could to reduce climate impacts on hydrology, redressing trends in which wet regions get wetter and dry regions get drier.
Lower temperatures would slow global sea-level rise and could curb the increasing incidence and strength of tropical cyclones.
But the scientists warn that solar geoengineering could compound some risks of climate change. Ocean acidification would still pose a threat to marine life if carbon-dioxide emissions were not slashed and sulphur dioxide might delay ozone regeneration in the stratosphere. In addition, whichever aerosol was used to filter out sunlight, more research would be needed on its impacts on health and the environment.
Further studies could be funded with the help of a new $400,000 (£284,000) fund from the Open Philanthropy Project. The fund could help scientists in developing nations study regional impacts of solar geo-engineering such as on droughts, floods or monsoons, said Andy Parker, a co-author and project director of the Solar Radiation Management Governance Initiative.
A UN panel of climate experts, in a leaked draft of a report about global warming due for publication in October, is sceptical about solar geo-engineering, saying it may be “economically, socially and institutionally infeasible.”