Geoengineering | Climate wizards

As global warming accelerates, the idea of ​​manipulating our planet’s climate appears increasingly attractive to some experts. A debate which, however, divides the scientific community regarding the possible breakthroughs of geoengineering. Should we bet everything on technology to compensate for our collective failure to reduce our greenhouse gas emissions?

The idea itself is not new. Nature itself offers examples of geoengineering that can be very effective in slowing the rise in temperatures on Earth. This is particularly the case for volcanoes: during an eruption, the plume of ash can help cool the atmosphere by blocking the Sun’s rays.

The eruption of Pinatubo, in the Philippines, in 1991, led to a drop in global temperature of 0.5°C in 1992. But it also killed hundreds of people, displaced thousands of others while hitting hard the country’s economy, it must be emphasized.

In a series of articles published on the theme “Buying time”, journalist Christopher Flavelle, from New York Times, has recently become interested in new breakthroughs in geoengineering. The idea put forward by certain scientists is that we need to give ourselves more time to reduce our polluting emissions when it is almost certain that it will be impossible to limit warming to 1.5°C, or even 2 °C above the level recorded at the start of the pre-industrial era.

With this in mind, the use of geoengineering would be temporary, just long enough to make the necessary changes in our societies to achieve carbon neutrality. An example would be releasing aerosols into the atmosphere to block the sun’s rays. A strategy, like others, which is far from unanimous, however.

Two camps oppose each other

In January 2022, around sixty researchers published a draft agreement not to use solar geoengineering, which has since garnered the support of more than 500 scientists around the world, including climatologist Michael Mann.

Their main argument is that “the deployment of solar geoengineering cannot be fairly governed globally and poses an unacceptable risk if implemented as a future climate policy option.”

A year later, in February 2023, around a hundred scientists, including American climatologist James Hansen, published an open letter calling instead for more research into geoengineering. “The current level of knowledge about MRS interventions [modification du rayonnement solaire] is not sufficient to detect, attribute or predict their consequences on climate risks. […] While we fully support research into MRS approaches, this does not mean that we support the use of MRS,” they nevertheless clarified in their missive.

We might have the impression that the scientific community is divided on this issue, but that is not really the case, believes Alejandro Di Luca, professor in the department of Earth and atmospheric sciences at UQAM.

“Because of the complexity of the climate system, this is the main argument why many of us are very uncomfortable with the use of geoengineering,” he adds. An issue which also makes him think of the film Cosmic denial (Don’t Look Up) where the authorities decide to use technology to recover the precious metals present on a comet which will destroy the Earth. A strategy which also leads to the destruction of our planet in this fiction by filmmaker Adam McKay.

A solution that is not a panacea

Alain Létourneau, professor of philosophy at the University of Sherbrooke, recalls that geoengineering does not allow us to tackle the problem, but rather to control the symptoms of climate change. “Everyone agrees that we need to reduce our emissions. This is the main thing to do. But it is clear that we continue, year after year, to increase the production of greenhouse gases,” he points out.

It is also in this context that he considers the possibility of using geoengineering. “If at a given moment, we had technological tools that allow us to give ourselves a few years of additional leeway to achieve a real transition, I think that this is also not a possibility that should be rejected. from the hand. »

The other side of the coin, he believes, is to make people believe that technology would prevent us from changing our behavior to achieve carbon neutrality. On this subject, the scientific community seems unanimous: geoengineering would only constitute an additional tool in the fight against climate change.

In addition to the technological issues, another question remains if we really had the possibility of manipulating the climate: who decides what, where and when we use geoengineering? The problem, according to Alain Létourneau, is that we do not currently have an effective governance framework to manage issues on a global scale.

Despite everything, Alejandro Di Luca and Alain Létourneau recognize that we should not deprive ourselves of doing research on different geoengineering techniques to better measure their ins and outs.

“There are also dangers in not doing research, so I’m a little torn about it all,” admits Alejandro Di Luca. Some technologies could be useful on a small scale, he says, but the devil is in the details, he says.

“We can clearly see that there is an energy transition that is indeed underway. We are in the process of doing things, points out Alain Létourneau. We might think we could get there [réduire nos GES] within a reasonable period of time, of the order of 20 years. But currently, we are told that we have 10 years to do it. If we had ways to give ourselves a few more years…”

“I’m not saying we’re going to do geoengineering. What I’m saying is that it’s going to cost us more if we don’t do adequate research to properly judge the different technologies. I think we have no choice, but we must do it in the scientific community, in conjunction with the democratic community,” adds Mr. Létourneau.

Some techniques considered

Imitate volcanoes

One geoengineering technique involves mimicking volcanoes, which disperse a plume of ash during an eruption. In 2022, American businessman Luke Iseman, founder of the company Make Sunsets, released two balloons into the sky on the Baja California peninsula, Mexico. The balloons contained sulfur dioxide, the substance also released by an erupting volcano. His experiment sparked an outcry in the scientific community.

Make the clouds shine

An experiment was carried out at the beginning of April in California when natural atmospheric particles (bioaerosols and sea spray) were released. The goal of the project led by researchers at the University of Washington was to make clouds brighter so that they reflect the Sun’s rays.

Iron in the oceans

By injecting iron into the oceans, we would stimulate the production of phytoplankton, which would increase the capacity of the oceans to absorb CO₂. An idea that seems simple at first glance, but whose consequences could be very serious for marine ecosystems.

A parasol for the Earth

Another solution imagined by astronomers and physicists would be to deploy a giant parasol in space, which would thus block part of the Sun’s rays which heat our planet.

The rain dance

Injecting silver iodide into clouds to cause rain is another variation of geoengineering, which could be used in the event of a severe drought, for example. A controversial technique, which scientists even describe as fraud on occasion. After last week’s torrential rains in the United Arab Emirates, rumors swirled that the Arab state’s cloud-seeding program was to blame for the disaster. “There is no technology capable of creating or even seriously modifying this type of precipitation,” Professor Maarten Ambaum, from the University of Reading, UK, told the trade media. New Scientist.