Dimming Sun’s rays could ease climate impacts in Africa

The 2017 'Day Zero' drought in South Africa left reservoirs barren
The 2017 ‘Day Zero’ drought in South Africa left reservoirs barren

Dialling down the Sun’s heat a notch by injecting billions of shiny sulphur dioxide particles into the stratosphere could curtail devastating drought across parts of Africa, new peer-reviewed research has reported.


This form of solar radiation management would slash the risk of another “Day Zero” drought in Cape Town, South Africa—a city of 3.7 million which ran out of water in 2017—by as much as 90 percent, according to a study published last week in Environmental Research Letters.

Global warming to date—just over one degree Celsius since the mid-19th century—enhances the likelihood of such droughts by a factor of three, earlier research has shown.

Allowing temperatures to increase another degree to 2C above preindustrial levels would triple the risk again.

The 2015 Paris climate treaty, signed by virtually all the world’s nations, calls for capping global warming at “well below” 2C, a goal many experts fear is rapidly slipping out of reach.

As the likelihood that global warming will exceed these limits increases, scientists and policymakers are taking a serious look at “geo-engineering” schemes to cool the planet that were rejected not long ago as dangerous science fiction.

“People working on climate change are waking up to the fact that if cutting emissions doesn’t prove sufficient to limit warming to 2C, then blocking out some sunlight could be our only hope of achieving that,” Andy Parker, project director for the Solar Radiation Management Governance Initiative, told AFP.

"It's not a pleasant thought, but we may have to decide whether it is riskier to reflect away sunlight, or risker to go ove
“It’s not a pleasant thought, but we may have to decide whether it is riskier to reflect away sunlight, or risker to go over the 2C threshold.”

A risk either way

“It’s not a pleasant thought, but we may have to decide whether it is riskier to reflect away sunlight, or risker to go over the 2C threshold.”

The study on Cape Town ‘Day Zero’ droughts is one of a dozen funded by Parker’s organisation, which promotes both research on the potential impact of solar radiation management (SRM) on the developing world, and the work of scientists from these regions.

“Developing countries are most susceptible to climate change, and are really poorly represented in SRM research,” he said by phone.

The SRM Governance Initiative takes no position on the merits of solar radiation management (SRM), and is funded entirely by non-industry philanthropy.

“SRM has the potential to be very helpful or totally disastrous—no one knows at this stage,” Parker said. “We need more information to make that decision.”

In the Cape Town study, an international team led by Romaric Odoulami found that blocking a tiny amount of solar radiation with reflective aerosols could keep global temperatures at 2020 levels.

Compared to a “worst case” scenario in which humanity continues unabated carbon emissions, SRM would by 2100 reduce the risk of a “Day Zero” drought along the southwestern tip of South Africa by 90 percent.

A man collects drinking water from taps that are fed by a spring in Newlands on May 15, 2017, in Cape Town
A man collects drinking water from taps that are fed by a spring in Newlands on May
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