Billionaire Philanthropists Want Us to Really Consider Dimming the Sun

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Call it “sunscreen for the Earth” or stratospheric aerosol injection, but the idea of dimming the sun to buy time for humanity amid accelerating climate change is having another moment in the spotlight. 

Some prominent billionaire philanthropists have in recent weeks thrown money and/or their reputations behind the idea of using particulates to reflect sunlight and therefore heat. Not to be left out, the U.S. government and startups are also ramping up their activity on this front.

Perhaps most prominently, the financier, mega-donor and conspiracy theorist target George Soros made headlines this month when he announced at a security conference that he supported a plan to spray seawater into the atmosphere to shield the fast-melting Arctic from the sun.

Facebook and Asana co-founder Dustin Moskovitz and his wife, former journalist Cari Tuna, also publicly joined the ranks of billionaires backing solar geoengineering this month. Open Philanthropy, a fund primarily supported by the couple, recently sent $900,000 to a network of scientists in Africa, Asia and South America to study such measures. 

Government funding is also beginning to flow, three years after Congress quietly directed the U.S. National Oceanic and Atmospheric Administration to develop a program, following lobbying from SilverLining, a solar geoengineering-focused nonprofit. The government’s program now spends nearly $10 million a year, reports Science. And late last year, the White House released a five-year plan to research such climate interventions.

As usual for the field, there is also controversy. A startup, Make Sunsets, has been in the news for its widely criticized sell-carbon-credits-now, sort-out-the-details-later approach, relying on YouTube videos and Home Depot runs to launch balloons bearing sulfur dioxide into the upper atmosphere. Kelly Wanser, the executive director of SilverLining, which is backed by both foundations and billionaire donors, denounced the startup as “selling snake oil.” According to Time, Wanser’s statement sparked so much public outcry in Nevada, where Make Sunsets made their latest release, that the governor’s office called the startup to investigate. 

Billionaires and controversy have gone hand-in-hand with solar geoengineering for quite some time now. Yet in addition to these high-profile efforts, there are small signs of widening interest within philanthropy, including from legacy institutions. With living billionaires dominating environmental philanthropy, it seems likely there will only be more backers signing on in the years ahead. And amid accelerating climate chaos, it may be that more foundations and philanthropists will see such measures — which backers typically liken to chemotherapy or a last resort — as something that must be investigated.

Billionaires are the biggest backers, but they’re not alone

To the extent that there is a solar geoengineering field, it owes a lot to philanthropy, and particularly billionaires. Mega philanthropists like Bill Gates and John and Laura Arnold were early backers of such research, as well as others like Rachel Pritzker, who sits on SilverLining’s board. I covered these supporters and others in a survey of the philanthropic landscape for solar geoengineering in February 2021.

Soros’ speech got a lot of attention, but it’s not completely new information. Staff at Open Society Foundations told me back in 2021 that solar radiation management would be part of a $40 million climate portfolio they had recently launched. We now know there’s buy-in from the very top for that funding. 

There are now two solar geoengineering backers who derived their wealth from Facebook: Matt Cohler, who was employee No. 7 at the social media company, and now Moskovitz. And Mark Zuckerberg is backing adjacent – and sometimes conflated – carbon removal efforts, technology that, through one method or another, pulls carbon dioxide from the air. The Chan Zuckerberg Initiative was recently in the news for backing a company aiming to design the first-ever purpose-built plant to use geothermal heat to power direct air capture. Lesser-known tech figures like venture capitalists Chris Sacca and Bill Trenchard were other initial supporters.

It makes sense, of course, that tech titans would focus on new technology as a solution for climate change. In a recent piece, Time reporter Alejandro de la Garza acerbically summed up why so many billionaires from the sector are “obsessed” with solar geoengineering:

“If your life story involved working really hard on some stuff in your 20s, and then it paying off so substantially that you’re able to spend the rest of your life working on passion projects while everyone around you tells you what an awesome, cool genius you are, you’re probably not, on a fundamental level, too excited about some sort of society-level change. In your experience, things have worked out really well, so therefore, the thing we’ve got going right now is probably pretty good. But also this climate change stuff is definitively not-good. What to do?”

Legacy funders, however, have not been entirely absent from the scene — and new players are emerging. The William and Flora Hewlett Foundation and Sloan Foundation both supported early research. And the Gordon and Betty Moore Foundation is now listed among SilverLining’s supporters. The smaller but still substantial Bernard and Anne Spitzer Charitable Trust is also a newly public backer, and a rare one from outside the tech world.

What’s next?

The year is 2025 and an unprecedented heat wave has just struck India. Tens of million people are dead, whole towns and cities wiped out by temperatures too great for human bodies to endure. In response, the Indian government takes drastic unilateral action, deploying jets to release sulfur dioxide into the atmosphere to replicate the cooling impact of a volcanic eruption. Solar geoengineering has arrived.

Thus begins science fiction writer Kim Stanley Robinson’s Ministry for the Future, a 2020 novel that explores how we might get to a point where governments and others resort to hotly contested measures like dimming the sun. While it’s easier to imagine the U.S. or China making such a move, based on historical precedent, the larger point is clear. Billionaires are largely dominating and funding this debate right now, but accelerating chaos could, in theory, push it into another gear. 

There remain many reasons to be skeptical. Foremost is a concern that pursuing measures would dissuade governments, corporations and individuals from making the changes necessary to cut emissions, which opponents and supporters of solar geoengineering agree should be our priority. There is also very little certainty about whether such a measure would unleash a new series of catastrophes, with some research finding it would acidify the ocean or impact the monsoon season. There have been volcanic eruptions, such as Mt. Pinatubo in 1991, that both spewed sulfur and lowered global temperatures. But humans’ record of interventions on that scale is decidedly mixed.

For proponents, it’s critical that we investigate the strategy further, particularly possible side effects, so we know whether this tool of last resort is effective and feasible or incalculably destructive. For opponents, research is at best a waste of resources and at worst like laying Checkov’s gun on the table. It will, as the principle dictates, inevitably be fired.

Many of those holding the biggest purses — billionaires and government — clearly fall into the first camp. It’s hard to tell for sure whether their interest is preventative, hopeful or both. Yet the world seems to be fast approaching the point where, ready or not, someone might try to pull that trigger.

Just this week, a group of 60 scientists published an open letter calling for deeper study of methods to cool the earth by reflecting sunlight — and soon. They emphasized, as others have pointed out, that existing pollution already shields the earth from as much as a third of historical warming. Reducing our emissions, in other words, could actually warm the climate in the short term by pulling back that shield.

After all, 2025 — the date of the novel’s haunting opening — is less than two years away. And emissions keep rising.