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The sun disappears behind natural fog in Baden-Württemberg on Sunday
Photo: Thomas Warnack / dpa
Scientists and environmentalists have warned against plans to artificially reduce global solar radiation in the fight against global warming.
In a letter published on Monday in the journal Wires Climate Change, the experts write that such a global intervention "cannot be regulated in a fair, inclusive and effective manner".
National governments and the UN should therefore prevent a "normalization" of such measures.
The more than 60 signatories include the President of the Federal Environment Agency, Dirk Messner, and climate change expert Frank Biermann from the University of Utrecht.
Under the term »solar geoengineering«, various possibilities are being discussed as to how people could artificially reduce the intensity of solar radiation and thus global warming.
One option would be to inject sulfur into the atmosphere en masse, creating tiny airborne particles that, like clouds, reflect solar radiation back into space before it reaches the Earth's surface.
A similar effect is known in nature after large volcanic eruptions or meteorite impacts.
Missing monsoon and dry Amazon
While such technological measures against climate change could theoretically stop warming, the regional effects would be devastating according to various studies. Thus, artificially weakening the sun's radiative power would likely interrupt the monsoon rains in South Asia and West Africa. It could wipe out the rain-dependent agriculture there that feeds hundreds of millions of people. The Intergovernmental Panel on Climate Change (IPCC) recently warned that this could also result in drought in the Amazon region in Latin America.
The scientists are also worried about what could happen if the artificial supply of the particles in the atmosphere suddenly ended.
In that case, the IPCC warned that "surface temperatures would very likely rise rapidly."
In addition, the technology would do nothing to counteract the ongoing accumulation of greenhouse gases such as CO₂ in the atmosphere.
Flagship project stopped in Sweden
Such methods are not to be expected in the near future anyway. Although US President Lyndon B. Johnson's scientific advisors suggested solar engineering as a way of counteracting growing concentrations of greenhouse gases as early as 1965, little progress has been made since then. Last year, a high-profile research project called Scopex met with opposition. Harvard University wanted to imitate the cooling effect of volcanic eruptions in the atmosphere from a test balloon over Sweden with small, reflective particles at an altitude of 20 kilometers.
The Sámi Reindeer Herders Council said it violated their culture's basic principle of living in harmony with nature.
"We haven't heard from them since then," protest leader Åsa Larsson-Blind told Reuters.
"If it's the public battle for Harvard versus indigenous peoples, we can't go ahead," admitted David Keith, a physics professor who worked on Scopex.
Harvard is now considering trying to start somewhere else, but maybe calling it off altogether.
Supporters also want a UN resolution
The proponents of solar geoengineering also form alliances.
According to Janos Pasztor, executive director of the Carnegie Climate Governance Initiative, "diplomatic work is going on behind the scenes."
The aim is for the UN General Assembly to discuss the technology for the first time from September 2023.
The Paris Peace Forum plans to set up a commission of former leaders in the coming weeks to propose options if global temperatures rise above the 1.5 degree target of the Paris climate agreement.
The body, headed by ex-WTO Secretary General Pascal Lamy, will also discuss solar engineering, said coordinator Adrien Abecassis.
Switzerland is considering a resolution on climate-changing technologies at the UN Environment Assembly, which is likely to meet in April.
The Confederation had already submitted such a draft in 2019, but withdrew it after only ten other nations supported it.
The non-profit organization Degrees Initiative has created a fund called Decimals, which promotes research projects into what has been classified as "controversial" "management of solar radiation".
Degrees director Andy Parker commented that the world faces “the big question: what are our options if cutting emissions proves to be insufficient?”
Private projects should also be stopped
The signatories to the opposing letter, however, warned that the discussion about geoengineering could raise hopes for a quick solution to the climate problem without addressing its root cause - the unsustainability of the economy.
According to him, this could prevent governments, companies and society from "doing their utmost to achieve decarbonization or carbon neutrality as quickly as possible".
There is currently no system that could monitor geoengineering programs.
In theory, it would be possible for a country or even a single billionaire with rocket technology to launch such a project single-handedly.
The letter therefore calls for an international agreement on the renunciation of such projects.
This was intended to ban the funding of geoengineering experiments.
The experts also demanded that no patents should be granted for such technologies.
ak/AFP/Reuters
