Research into geoengineering may be necessary, says the UN

Limiting global temperature rise to no more than 1.5˚ C, or 2.7˚ F, means reduction of greenhouse gas emissions in the near term, according to the United Nations. But humanity is better off with a few aces if it can’t be done in time. If climate scenarios shift to true apocalyptic truthsthe world may have to use stop-gap solutions that artificially slow the pace of warming by adjusting how much the sun warms the earth.

Solar geoengineering, also known as solar radiation modification (SRM), can do just that. SRM consists of a speculative group of technologies that, in theory, could reflect some of the sun’s energy back into space, balancing the increase in earth’s temperature. Examples of the large family of proposed SRM technologies to cool the planet include injecting aerosols into the stratosphere to make it more reflective and placing large mirrors in orbit to limit the amount of sunlight reaching the earth.

SRM technologies are far beyond the reach of today’s economy, and even climate scientists caution is urged how they can change the natural processes of the planet. The UN Environment Program and an expert panel recently conducted a scientific review of SRM technologies and released its findings in a report published on Monday. While the UN recognizes that the technology carries many risks and recommends that it not be deployed anytime soon, it also acknowledges that the situation could change quickly if attempts to reduce greenhouse gases fail.

“The expert panel considers that a near- and mid-term large-scale deployment of SRM is not currently necessary and unwise,” the report said, but added: “This view may be -or if climate action remains insufficient.”

Extreme measures

In recent years, governments and companies have taken many steps to decarbonize and reduce greenhouse gas emissions, and the worst climate scenarios seem to less likely than before.

But by the UN’s own admission, current efforts to reduce emissions are not enough to avoid a climate catastrophe.

Policies and pledges to reduce emissions “remain insufficient to limit global temperature increases to 1.5˚ C by the end of the century,” the UN announced in October report. The UN says current commitments are “woefully short” and puts the world on track for 2.5˚ C of warming by 2100, more than the threshold considered acceptable or safe by the scientific community. And keeping the temperature to the 1.5˚ C goal of the UN is probably impossible without artificial carbon removal already in the atmosphere, the researchers say.

If the climate warms more severely, reducing emissions may not be enough to avoid the natural disasters, mass migrationand widespread hunger and poverty that comes with higher temperatures, and the world may have to consider drastic measures.

Research, not implementation

Solar geoengineering represents “the only known method that can be used to cool the Earth within a few years,” the UN report on SRM says, adding that the technologies to deploy SRM, while nothing today, far from science fiction.

“There are no known prohibitive technical barriers,” the UN said, adding that solar geoengineering technology could be “developed in less than ten years.”

But there is little research on what side-effects technology has on climate and biological life on earth. Philanthropic billionaires including Bill Gates has been investing in geoengineering research for years, and the scientific community may be starting to catch on as well. On Monday, the same day the UN report was released, a group of more than 60 scientists from prominent institutions around the world signed. an open letter urges the international community to invest more resources in researching the costs and feasibility of solar geoengineering, because the goals of reducing emissions seem unattainable.

“The current level of knowledge about SRM interventions is not sufficient to identify, describe or plan their consequences for climate risks,” the scientists wrote.

But like the UN, scientists are still cautious about advocating for these strategies, at least until more is known about their potential consequences.

In a statement Along with Monday’s report, the UN said that SRM is “no substitute for the rapid reduction of greenhouse gas emissions, which must remain a global priority.” An important obstacle is its cost. Deploying solar geoengineering at scale is likely to cost tens of billions of dollars a year for each level of cooling, the UN has found, a cost that may prove unsustainable because the SRM technologies will probably need to be applied for decades or even centuries to achieve the desired level of. cooling, without even considering the costs of mitigating SRM’s unintended impact on the planet.

Those unknown consequences may be the biggest obstacle to deploying SRM at scale, which the UN says could “introduce new risks to people and ecosystems.” The potential effects include irreversible damage to the ozone layer, exacerbating the effects of climate change at local scales, and, if the technology is suddenly disrupted, leading to higher levels of warming. .

The scientists who wrote the open letter advocating for more research emphasize that they have not yet supported the implementation of the technology, and are well aware of its potential consequences. But as more climate thresholds are crossed and tipping points continue to decrease, knowing more about the technologies at our disposal certainly can’t hurt.

“While we fully support research into SRM methods, this does not mean we support the use of SRM,” the scientists wrote. “We support a rigorous, rapid scientific assessment of the feasibility and effects of SRM methods especially because such knowledge is a critical component in making effective and ethical decisions about SRM implementation. .”

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