Dimming the Sun’s Rays Should Be Banned, Experts Say

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Scientists have long known that injecting large amounts of reflective particles into the upper atmosphere could cool the planet.

Planetary-scale engineering projects designed to cool the Earth’s surface and mitigate the impact of global warming are potentially dangerous and should be blocked by governments, more than 60 political and scientific experts said on Monday.

Even though the injection of billions of sulfur particles into the middle atmosphere – the most controversial plan for so-called solar radiation modification (SRM) – returned a critical fraction of the sun’s rays as expected, the consequences could outweigh the benefits, they argued in an open letter.

“The deployment of solar geoengineering cannot be governed globally in an equitable, inclusive and effective manner,” the letter states, supported by a comment in the newspaper. Climate change.

“We therefore call for immediate political action by governments, the United Nations and other actors to prevent the normalization of solar geoengineering as a climate policy option.”

An increase of 1.1 degrees Celsius over mid-19th century levels has already increased the intensity, frequency and duration of deadly heat waves, droughts and megastorms.

The world’s nations have pledged to limit the Earth’s surface temperature rise to 1.5C above mid-19th century levels, but UN-backed scientists say this threshold would be exceeded, perhaps within a decade.

The failure to reduce greenhouse gas emissions that drive global warming has led some policymakers to embrace solar geoengineering – widely dismissed not so long ago as more science fiction than of science – to buy time for a more sustainable solution.

It has long been known that injecting large amounts of reflective particles into the upper atmosphere could cool the planet.

Nature sometimes does the same thing: Debris from the 1991 eruption of Mount Pinatubo in the Philippines lowered the Earth’s average surface temperature for more than a year.

But the open letter says there are several reasons to reject such a course of action.

The artificial attenuation of the Sun’s radiative force is likely to disrupt monsoon rains in South Asia and West Africa, and could devastate rainfed crops on which hundreds of millions of people depend for food, according to several studies.

Unintended consequences

“Stratospheric sulfate injection is weakening the African and Asian summer monsoons and causing the Amazon to dry up,” the Intergovernmental Panel on Climate Change (IPCC) said in its latest scientific assessment.

Other regions, however, could benefit: a study last year concluded that SRM could greatly reduce drought risk in southern Africa.

Scientists also worry about the so-called terminal shock if the seeding of the atmosphere with sun-blocking particles were to suddenly stop.

If the SRM “were discontinued for any reason, there is high confidence that surface temperatures would rise rapidly,” the IPCC said.

Moreover, the technology would do nothing to stop the continued buildup of atmospheric CO2, which is literally altering the chemistry of the ocean.

The open letter also warns that raising hopes for a quick climate fix “may discourage governments, businesses and societies from doing everything possible to achieve decarbonization or carbon neutrality as soon as possible.”

Finally, there is currently no global governance system to oversee or implement solar geoengineering programs, which could be implemented today by a single country, or even a billionaire with rockets.

The open letter calls for an “international non-use agreement” that would block domestic funding, bad outdoor experiences and deny granting patent rights for SRM technologies.

Such an agreement “would not prohibit atmospheric or climate research as such,” the letter states.

Signatories include Frank Biermann, Professor of Global Sustainability Governance at Utrecht University; Aarti Gupta, Professor of Global Environmental Governance at Wageningen University in the Netherlands; Professor Melissa Leach, Director of the Institute of Development Studies in Sussex, England; and Dirk Messner, President of the German Environment Agency.


Dimming the Sun’s Rays Could Mitigate Climate Impacts in Africa


© 2022 AFP

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Dimming Sun Rays Should Be Banned, Experts Say (2022, Jan 17)
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