Geoengineering inches closer to reality

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This article was published 16/05/2025 (315 days ago), so information in it may no longer be current.

Armed conflicts and trade chaos have evidently displaced climate action from international attention. A reported decision by the U.K. government late last month, for example, would have previously triggered major backlash.

Instead, it barely registered.

On April 22, the Telegraph newspaper claimed Britain will soon greenlight several solar geoengineering projects. Doing so may advance a highly controversial Plan B for mitigating climate change.

Still mostly hypothetical, the practice involves man-made interventions in the atmosphere and environment to produce a sharp — but brief — drop in temperatures. Solar geoengineering in particular aims to mitigate global warming by blocking between one and two per cent of sunlight from reaching the Earth’s surface.

Proposed methods seem torn from the pages of science fiction. They include spraying aerosol particles into the sky to brighten clouds or copy the shading effect of airborne ashes after a volcanic eruption.

More radical ideas envision placing a legion of mirrors in space to bounce sunlight away from the Earth. Or genetically modifying plants to have brighter leaves.

Fifteen years ago, America’s energy secretary championed repainting millions of rooftops and vast stretches of pavement white. Some scientists want to preserve the reflectivity of melting polar icecaps by blanketing them in layers of powdered glass or silicon beads, or millions of wind-powered snow blowers.

Yet there are massive complications.

Once deployed, the effects of geoengineering would only be temporary. Unless overall carbon emissions are reduced in parallel, the practice must be maintained to avoid a “termination shock” — where temperatures spike above prior levels after the intervention wears off.

What’s more, no one really knows what will happen if it’s ever used.

Computer modelling and some small-scale experiments to date have been positive. But the full effects of the technology will remain impossible to understand unless it’s deployed for real at a global scale.

In essence, many of the suspected side effects of hacking the atmosphere are predicted to mirror the same impacts forecast for more advanced stages of climate change — aggravated weather volatility, abrupt sea level rises, sudden floods or drought conditions and biodiversity loss.

Experts have cautioned that such manipulation of planetary weather patterns will also inevitably benefit some regions more than others. The difference is that lowering the so-called “global thermostat” may relegate these consequences to certain areas rather than making them universal, as runaway climate change would. This may ultimately incentivize affluent nations to embrace the practice as an acceptable alternative to the complex task of drastically curtailing their emissions.

Indeed, geoengineering promises to be very cheap compared to conventional green strategies. The cost of intervention necessary, in theory, to reduce global temperatures by 0.5 degrees Celsius within months is between US$10 billion to US$15 billion. To achieve the same effect decades from now through scaling up existing clean energy technologies is pegged to be at least US$4 trillion annually.

Plus, ongoing decarbonization efforts are already being hindered by bottlenecks in supply chains, economic protectionism and renewed great power rivalry.

What’s more, the climate plans of large emitters mostly hinge on the massive future expansion of unproven carbon capture and storage technologies. And even if these policies are achieved — no sure thing — they put the world on a collective path toward around 2.5 C of warming above pre-industrial levels by 2100.

“Humanity has opened the gates of hell,” UN Secretary General António Guterres warned about climate change at the 2023 UN General Assembly. Fearing the worst, many governments and non-state actors increasingly view geoengineering as a possible contingency measure.

The Biden administration released a report in June 2023 acknowledging that geoengineering could hold future value. The number of private foundations offering funding for research has exploded. In February 2024, at a UN climate conference in Nairobi, the executive director of the UN Environment Programme recommended a “global conversation” about the practice.

Not everyone agrees. Hundreds of scientists have issued an open letter demanding an international treaty banning solar geoengineering. Their call has since been endorsed thousands of civil society groups, as well as governments in Africa and elsewhere across the developing world — nations that would struggle most to cope if geoengineering goes awry.

But the prospects for a non-use agreement are shrinking. At least 50 countries are already using weather-modifying technology, led by China and Gulf States. And proponents maintain there is an ethical imperative of exploring geoengineering as a last-ditch strategy that might suspend global heating long enough for more aggressive climate policies to take hold.

This may be a morally dubious argument; it also might not be wrong. Only time will tell.

Kyle Hiebert is a Montreal-based political risk analyst and former deputy editor of the Africa Conflict Monitor.