CLARA FERREIRA MARQUES: What if we blotted out the sun to fight global warming?

Apocalyptic scenes open The Ministry for the Future, the latest novel by science fiction writer Kim Stanley Robinson. India is hit with a calamitous heatwave — one so sweltering, with humidity so high, that bodies struggle to sweat, and therefore to survive. Thousands die in the sun-heated waters of a lake where they had sought refuge. In the end, 20-million perish. 

Grappling with the upheaval and fury that follow, India breaks an international agreement governing climate engineering and injects vast quantities of sulphur particles into the atmosphere in a desperate attempt to cool the subcontinent. “Everyone knows, but no one acts,” an official says. “So we are taking matters into our own hands.”

Robinson’s tale is fictional. But it is set only a few years into the future, and the climate disaster he describes, along with the technology and diplomatic conundrum, are not made up. Those are all too real. Insufficient understanding and the underdeveloped governance of such options means the world is no better prepared in reality than in fiction when it comes to radical interventions, in particular when it comes to the contentious question of solar geoengineering.

But does that mean, as a group of scientists have argued in an article published in January, that we should effectively ban the nascent technique now?

Solar geoengineering covers a range of proposals to cool the earth by reflecting some sunlight back into space, including with stratospheric aerosol injection as in Robinson’s novel. It’s fast-acting, in climate terms, but does not tackle the underlying cause of the global warming problem and is high risk if it goes awry. It’s an option no-one wishes to see in action.

Still, the idea of a non-use agreement that effectively halts support for research & development, as advocated by this coalition of academics, should give us pause. Given the gravity of our climate predicament, and the likelihood the world will overshoot its global warming limit or hit tipping points, this option is simply not yet one we can discard —  at least not before understanding it further. For now, it’s terrifying and terrible in the way that chemotherapy is: we don’t want it, but can we deny ourselves the possibility? It’s no substitute for dramatic carbon reduction, but do we know enough today to refuse it?

We need to see the world as it is, not as it should be. As Jesse Reynolds, senior policy officer at the Global Commission on Governing Risks from Climate Overshoot at the Paris Peace Forum, put it to me, solar geoengineering is a risk-risk trade off, and must be understood in that context: there is no low-risk path forward. 

The arguments against solar geoengineering are to some extent familiar. The most common posits that this sort of technology is at best wishful thinking and at worst a distraction, when the world should be concentrating on dramatic reductions of carbon emissions to limit global temperature rise to 1.5°C, the ambition laid out in the Paris Agreement. Certainly that climate goal is clear, and governments like Australia’s, hiding carbon inaction behind future technological miracles, should be called out.

The second, related, argument is that discussing and researching solar radiation management risks normalising it, creating a technological slippery slope that locks humanity in. It’s not clear this would happen with a technology that is not in private hands, and it worryingly implies knowledge alone is toxic.

Dismissing what we do not understand is an even bigger wager than a bet on limited and controlled research. What happens if, as in the novel, it is deployed unilaterally? Not to mention that, as Daniel Bodansky and Susan Biniaz point out in a 2020 article, research into climate intervention can actually help bring governments’ “magical thinking” on technology down to earth.

Then there’s the idea, raised by the scientists arguing for a ban, that the technology is impossible to govern in an inclusive and just manner. That, they argue, would require “effective and enforceable political control by the Global South”. The governance challenge is enormous, but does that make it impossible? Even research? Or is the standard here simply impossibly high?

To be clear, solar radiation management in most of its forms — bar, perhaps, painting roofs white —  does come with peril. Uneven application could cool one region but alter vital rain patterns elsewhere. Understanding the already changing planet could become harder. A sudden stop to it for reasons of human error, financing, even politics or war would be devastating, an idea known as termination shock. If we ever get that far, the question of who deploys it, where and to what degree, is even more fraught. Because the engineering costs are relatively modest and the technology powerful, overkill is a possibility.

But the debate is not yet at whether we should pull that lever. Indeed, the world can credibly put in place a moratorium on the deployment of solar geoengineering. But research, responsibly managed, is vital and not impossible to imagine.

First, support research with public funds. Guide and regulate. Provide an agreed code of conduct that could be based on the existing Oxford Principles that includes local permitting, transparency requirements and a stakeholder process that puts in place public consultation. Full disclosure and information sharing in particular will be crucial.

Then, begin to tackle the governance gap. Climate intervention is not without rules — a plethora of treaties already exist, covering air pollution, biological diversity, marine waste. The duty to do no harm is a widely recognised principle of customary international law.  Yet troubling empty spaces still abound.

• Ferreira Marques is a Bloomberg Opinion columnist covering commodities and environmental, social and governance issues.