Solar geoengineering projects intended to cool the Earth’s surface and limit global warming are potentially dangerous, experts and scientists say (AFP/CHANDAN KHANNA)
Solar geoengineering projects intended to cool the Earth’s surface and limit global warming are potentially dangerous and should be blocked by governments, argue 60 experts and scientists in a letter published Monday.
Injecting billions of sulfur particles into the upper atmosphere — one of the most controversial intentional solar modification projects — could reflect some of the sun’s rays, but the side effects may outweigh the benefits, insists this open letter accompanied by a text in the journal WIREs Climate Change.
“The deployment of solar geoengineering cannot be managed globally in a fair, inclusive and effective manner. We therefore call on governments, the UN and other actors to take immediate political action to prevent the normalization of solar geoengineering in as an option against global warming”, write the signatories.
The planet has gained approximately +1.1°C since the pre-industrial era, already leading to an increase in heat waves, floods and storms.
The world is committed to limiting this warming to well below +2°C, +1.5°C if possible, but the UN climate experts (IPCC) estimate that the threshold of +1.5°C could already be reached around 2030.
Temperature anomalies identified each year in the world, between 2002 and 2021, compared to the average for the period 1981-2010 (AFP / )
And faced with the failure to reduce global warming CO2 emissions, some politicians are now supporting geoengineering, to buy time.
Scientists have long known that injecting large volumes of reflective particles into the upper layer of the atmosphere could cool the planet. Projections from the eruption of the Pinatubo volcano in the Philippines in 1991 reduced the Earth’s average surface temperature for a year.
But the open letter above all highlights the risks.
An intentional modification of solar radiation could, for example, disrupt the monsoon regime in South Asia and West Africa and could thus destroy the crops on which hundreds of millions of people depend, according to studies already published.
And if the modification of the radiation ends “for whatever reason, it is very likely that the surface temperature would increase rapidly”, estimates the IPCC.
Monthly evolution of the atmospheric concentration of carbon dioxide and methane, since 2003 ( AFP / )
Moreover, this technology would not prevent CO2 from continuing to accumulate in the atmosphere.
The signatories, such as Professor Aarti Gupta of the Dutch University of Wageningen or the President of the German Environment Agency Dirk Messner, are also concerned about the risk of creating false hope for a solution to global warming, which could “dissuade governments, businesses and corporations from doing everything possible to achieve carbon neutrality as soon as possible”.
Finally, experts point to the lack of governance to oversee these projects.
So the open letter calls for an “international non-use agreement” that would block funding, testing and patenting of these technologies, without stopping scientific research.
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