2023-05-20 07:05:03
Published on :
Tackling the effects of global warming rather than the causes is the raison d’être of geoengineering. A niche on which several start-ups have launched. But trying to modify the climate, artificially, is not without consequences.
From our correspondent in Houston,
Last February, the American startup, Make Sunsets, begins a somewhat special experiment. Luke Iseman and his sidekick Andrew Song, the two co-founders of the startup, are in Nevada and they plan to send balloons filled with sulfur dioxide into the atmosphere. They plan to put an idea into practice: reflect the sun’s rays to lessen the greenhouse effect and slow down global warming, by reducing the amount of solar radiation received by the earth and the atmosphere. And to do this, they want to create a kind of reflective screen in the atmosphere, a ” sunscreen for the earth they like to say.
This technique is called climatic engineering or geo-engineering. The two young men rely on serious studies which prove that when the eruption of Mount Pinatubo, in the Philippines, in 1991, released thousands of tons of sulfur dioxide into the stratosphere, the global temperature of the earth then dropped. on average about 0.5°C for 2 years*.
The two inventors, rather than being supplied with sulfur dioxide, will generate it alone, thanks to a tutorial seen on YouTube. With a simple barbecuethey burn a sulfur-based fungicide and capture the smoke emitted in garbage bags, then this gas is mixed with helium to inflate a balloon.
The first stage of the experiment works, three balloons and analysis equipment fly away. Even if the start-up has not yet published the results of its experiment, it has already won 750,000 dollars of investment, and proposes, against 10 dollars, to send 1 gram of sulfur dioxide into the stratosphere, this which, according to Make Sunsets, would be equivalent to canceling one ton of CO2 emissions over a year.
« One of the worst possible scenarios »
But for Harvard environmental science professor Peter Frumhoff, “climate engineering is one of the worst possible scenarios for combating the climate crisis”. Peter Frumhoff is also one of the experts of the IPCC, he is at the forefront of analyzes of climate change and the measures proposed to avoid the worst.
Because penny dioxidefre can be deadly. It can also have secondary effects in the atmosphere, including generating acid rain, but also creating local climate changes. « It is nevertheless a scenario that must be taken seriously, experienced and supervised, he continues. It won’t be for long-term use, but it could save us time.” while waiting for real solutions to be put in place. Moreover, last October, the White House launched a five-year research plan to study ways of modifying the quantities of light received by the Earth to mitigate the effects of climate change.
The use of sulfur dioxide therefore, but also releasing aerosol particles into the stratosphere to create a mirror effect, or injecting sodium into the atmosphere to allow clouds to better reflect solar radiation, two other ideas within climate engineering. The idea of using this technique** however, remains highly controversial. A study by Harvard scientists, conducted in Sweden, was canceled in 2021 following opposition from environmentalists and local communities.
A cost greater than the benefits
Make Sunsets also caused a stir, when Luke Iseman flew his first test in mid-January from his home in California. The balloon carried by the winds flew over Mexico, the country where the startup planned to continue its experiments, but which did not appreciate and prohibited the overflight of their territory. For Peter Frumhoff, the approach of Make Sunsets is far too wild : « Given the environmental and ethical issues, governments and local communities that may be affected by the consequences of these tests must be involved. »
Because we must not forget that it is sunlight that allows vegetation to grow – the famous photosynthesis – and life to develop. Because of this, the harm from climate engineering could outweigh the benefits, which is why this technique has been shelved for decades – despite having been around since the 1960s.
Especially since today, scientists and governments fear that if the results are conclusive, many countries and companies will refuse to reduce emissions since it would be enough to inject billions of tons of sulfur dioxide into the sky. to compensate. At the risk of living surrounded by a cloud of sulphur. Not to mention that some states or organizations could use climate engineering as a weapon to modify the climate.
* Public data https://pubs.usgs.gov/fs/1997/fs113-97/
** There is also talk of developing planktonic algae in the astral ocean, or carbon sinks, among other ideas.
#geoengineering #controversial #innovation #niche