2023-07-27 11:30:00
CLIMATE – Why fight against global warming and its causes when you can manipulate the weather? This is the approach of geoengineering, a set of techniques aimed at modifying the climate to cool the Earth. As scientists, startups and billionaires like Bill Gates call for these technologies to “change in solar radiation”other organizations such as the UN or the European Union warn about the “risks and unintended consequences” and call for an international debate on their governance. What is it about ? Why is geoengineering so encouraged, particularly in the United States, as apprehended?
Faced with the difficulty, or even the failure, of reducing the CO2 emissions responsible for global warming, researchers and start-ups are turning to geo-engineering. The techniques for cooling the earth’s surface hitherto proposed and explored are numerous, but the most advanced are the injection of aerosols into the stratosphere and the “controlled stratospheric disturbance”.
Several experiments already carried out
Partially inspired by the eruption of the Pinatubo volcano in the Philippines in 1991, which lowered global temperatures by around 0.5°C for 2 years, the injection of aerosols into the stratosphere involves soaking the sky with particles of sulfur dioxide, capable of reflecting part of the sun’s rays back into space. This technique was explored in February 2023 by the American startup Make Sunsets. Its two co-founders, Luke Iseman and Andrew Song, burned a sulfur-based fungicide and captured the smoke in trash bags. This gas was mixed in a balloon with helium, in order to inflate it and make it levitate.
A first experiment has been carried out. Three balloons, equipped with analysis equipment, trackers and cameras, took off from Nevada. The startup has not yet revealed the results of its first test, but its idea was able to convince investors, who granted it more than $500,000. Customers have also expressed interest. “We have 2,790 orders from 58 paying customers that we haven’t delivered yet”Luke Iseman told CNBC. He and his sidekick claim that a single gram of sulfur dioxide “would cancel one tonne of CO2 emissions over a year”.
A similar experiment was carried out in March in the United Kingdom, according to the revelations of the MIT Technology Review, by researcher Andrew Lockley, in collaboration with European Astrotech. A balloon, named Stratospheric Aerosol Transport and Nucleation was launched at high altitude and released several hundred grams of sulfur dioxide into the stratosphere.
“The Controlled Stratospheric Disturbance Effect” dates back several years. This is a project by researchers at Harvard University called SCoPEx (Stratospheric controlled perturbation effect, note), which consists of sending a balloon or planes to disperse, not sulfur dioxide but extremely fine salt particles at an altitude of 20 km, that is to say between the ground and the stratosphere. The experiment, scheduled for 2021, was delayed after the refusal of Sweden and its space agency to carry out this test, following the refusal of indigenous populations, particularly the Sami (also called the Sami or “Lapps”). A decision accepted by the Harvard researchers, who announced the repatriation of their experiment to the United States, whose government expressed a “measured support” research in this area.
If the site dedicated to SCoPEx does not mention the billionaire Bill Gates, known both for having founded Microsoft and for having financed numerous research related to climate and biotechnology, several media like Forbes or Newsweek confirm its investment, without disclosing the amounts.
EU and UN concerned
A growing interest that has prompted reactions from institutions such as the European Union and the UN. In June, Frans Timmermans, Vice-President of the European Commission, warned of the risks associated with these technologies. “We see geoengineering being discussed and explored in many parts of the world and seen by some as a potential future response to climate change,” did he declare. “This is a matter that carries global indications and considerable risks; no one should experiment, alone, on our shared planet.”
Multidimensional risks since. “What will happen if some countries go it alone?”, he wonders again, appellant to an international debate. The United Nations Environment Program (UNEP) had already raised possibilities in its report “One Atmosphere”, published on February 28 and devoted to the risks associated with solar radiation management techniques.
The first risks are climatic. The technique of injecting aerosols into the stratosphere could cause “a regional overcooling in the tropics and a residual overheating in the polar regions”or “temperature asymmetries between the northern and southern hemispheres”. UN experts then warn against environmental damage. “To be effective, the deployment of such techniques must be sustained continuously for decades or longer.” If the deployment of aerosol injection into the stratosphere were ever to be halted, “the previously masked warming would manifest itself again in a few years” and the “serious adverse effects on ecosystems, biodiversity and species” caused by geo-engineering “would suddenly increase in intensity”.
Added to this is a problem “morale”, since these technologies are “court-termistes” and dominated, according to the UN, by “financial concerns”. Frans Timmermans also mentioned the geopolitical risk inherent in the governance of these techniques. What if sulfur particles injected into one country would impact the neighboring country, as was the case with Make Sunsets, which had to stop its experiments after protest from the Mexican government?
About 450 experts also called, in an open letter which relays their concerns, to an international agreement for the non-use of these geo-engineering techniques. “You can’t really get rid of all the uncertainties by laboratory experiments. But small-scale experiments can’t give us the full picture either.” argues one of the signatories.
#Cool #Earth #curb #global #warming #Geoengineering #techniques #spark #interest #among #researchers #concern