Pessimism grows about humanity’s ability to save the planet as world leaders prepare to meet for talks on climate change at the COP26 summit in Glasgow on October 31. Faced with increasingly apocalyptic projections, some scientists are calling for plans to geoengineer the planet to cool. But is this a realistic way out of the nightmare?
UN climate experts were unanimous in their latest report published in August: Unless we keep global warming below 1.5 degrees Celsius, the Earth will be hit by heat waves, cyclones and storms, entire species will disappear and large swaths of humanity will have to. they leave their homes when coastal settlements are under water.
As desperation grows over humanity’s ability to bypass this fateful threshold, researchers are considering geoengineering as a potential means of reversing the damage.
“Geoengineering is a way of using various technological tools to nullify the environmental effects of human actions,” explained Sofia Kabbej, a researcher at the Climate, Energy and Security Program at the French Institute of International and Strategic Relations.
Science fiction or reality?
Several ideas fall under the umbrella of climate geoengineering. Some seem totally fanciful, even dangerous. But other technologies are already operational.
“There are two categories of geoengineering,” said Roland Séférian, a climatologist at the French Meteorological Office.
The first, and the most controversial, refers to ways of “modifying solar radiation,” said Séférian. One such idea is “to reproduce what happens during volcanic eruptions when dust clouds emerge in the sky and form a kind of screen between the sun and the earth, cooling the atmosphere in the process.”
As things stand, this is still just an idea scientists are thinking about. But for several years, a team of Harvard University researchers led by scientist David Keith has planned to test it in real-world conditions. In 2021, this team intended to launch two balloons into the stratosphere in Sweden and release several kilos of calcium carbonate. However, loud opposition from the local population and numerous NGOs put an end to this project.
Another technique is to “whiten” cloud formations by spraying salt into the atmosphere to reflect more of the sun’s rays and consequently heat, thus limiting the warming of the oceans.
In 2020 a small-scale experiment was carried out in Australia. But research on this technology is still in its infancy. Dozens of similar plans have been suggested, some quite eccentric and of dubious plausibility, including placing mirrors in space and even modifying Earth’s trajectory.
The second category of geoengineering consists of projects to remove CO2 from the atmosphere. “Some potential means of doing this have already been widely explored,” said Séférian. Countless techniques are being considered, from using natural carbon sinks like forests or oceans to installing carbon vacuums in various locations and even placing filters in factories.
“One approach that we are already using a lot to try to tackle climate change is planting trees to capture CO2,” continued Séférian.
Outside of this natural environment of carbon sequestration, the IPCC report mentioned two technologies as possible methods for removing CO2 from the atmosphere.
The first is called direct air capture (DCA), which involves installing types of vacuum cleaners to suck CO2 out of the air. Then the carbon is buried underground. Some 20 such projects are already underway around the world, according to the International Energy Agency. The Swiss company Climeworks, for example, installed coal suction machines at a waste incineration plant in the Zurich region.
The second such technology is called Bioenergy with Carbon Capture and Storage (BECCS). This means producing energy by burning biomass, such as wood and agricultural waste, trapping the resulting CO2 and burying it underground.
So far, neither technology has proven its worth. The DCA seems inefficient and requires a lot of energy to function. Meanwhile, there may not be enough arable land to plant forests or use BECCS to make a significant difference in the fight against climate change.
The chimera of a quick fix?
But these geoengineering technologies worry many environmentalists. They fear that focusing on a technological solution will distract attention from the urgent task of drastically reducing CO2 emissions.
“To affect how the sun’s rays reach the earth would amount to giving humans a quasi-divine status,” Kabbei said. “And there is something quite troublesome about that.”
Some members of the political left, especially, may also be concerned that the oil companies are profiting handsomely from it. “It is a great financial opportunity for them,” Kabbei said. “Carbon capture can only occur by transporting CO2, which requires pipes and storage space; the type of infrastructure that oil companies have. ”
Another problem for some critics is that geoengineering is something that only countries in the world’s developed countries can afford to do, while underdeveloped countries are likely to suffer the worst effects of climate change.
And with geoengineering technologies still in an embryonic stage, scientists don’t know what unintended consequences they could create.
“Even with the best scientific models, it is difficult to see exactly what would happen if people tried to absorb or recover solar radiation,” said Séférian. “CO2 capture and storage also raises questions: What would happen if carbon leaks out during transport? How long could it stay buried?
Despite these concerns, given the way things are going, “we cannot be 100 percent certain that we will never need this technology,” said Olivier Boucher, an expert in geoengineering technology at the CNRS research institute in Paris. “We may find that these ideas do not work in practice, but in any case it would be a waste to deprive future generations of our work on these possibilities.”
“Anything to do with modifying solar radiation should be considered a last resort,” Boucher continued. “But, in my opinion, CO2 capture and storage techniques could really become tools to help fight global warming.”
Séférian agreed: “It is very likely that we will have to use CO2 capture technology to achieve carbon neutrality,” he said. “And the more we fall short of our current policies to address climate change, the more inevitable it will become, although, in an ideal world, we shouldn’t need to use it.”
In any case, the investigation continues, although there is no international framework that regulates it.
An international convention was adopted in 1976 prohibiting the use of “environmental modification techniques” for military purposes, but its scope is limited. States and private actors can thus develop their own projects as they see fit.
“Right now it’s the early days of geoengineering, but it will definitely become much more prominent in the coming years,” Kabbej said. “Therefore, the countries will have to start talks to agree on how it should be done.”
“There has to be a public debate,” added Séférian. However, it is not on the official COP26 agenda. “It’s certainly something we should be talking about, but it’s not a priority at this stage. The important thing is to reduce CO2 emissions. Geoengineering comes later. “