In my last paid issue here, I discussed the virtual certainty that a heat wave megadeath disaster is going to happen at some point. Heat already kills more people than any other kind of natural disaster, and many places are already creeping up to the limit at which even young, healthy people cannot survive sustained exposure. That includes large parts of the United States like southern Arizona, where deaths directly attributable to heat have greatly increased in the last few years, and many others are no doubt missed. A week of wet bulb temperatures over 95 in a place like Afghanistan could kill millions.
This line of reasoning often inspires outright despair. Here we are careening towards Second World War levels of carnage, and yet the best we can manage in the US is the Inflation Reduction Act—a worthy bill but still insufficient, and passed about 30 years after it was obviously needed.
Yet among environmentalists and other climate-focused types, there is often great resistance to the simplest and easiest way to stave off the heat apocalypse: solar radiation management (SRM). Just load up a fleet of custom cargo planes with some kind of reflective aerosol like sulfur dioxide, aluminum oxide, or possibly even ocean water, and spray enough into the stratosphere to cut incoming solar energy by a couple percent. It wouldn't solve everything about climate change, but it would address the principal problem driving most of its bad aspects: excess energy in the oceans and atmosphere.
It would cost maybe $20-200 billion per year—within the grasp of the biggest rich and medium-income countries, or a group of smaller medium-income ones.
A lot of people really hate this idea. It would have unknown effects on weather patterns, it would reduce the incentive to cut emissions, it would not do anything about ocean acidification, if you use sulfur dioxide it will probably damage the ozone and cause some acid rain, if we were to start SRM and then stop abruptly it might be worse than letting climate change rip, there is a risk of overshooting and causing an ice age, and so on. Then there is an incredulous stare reaction pointing out that we would be responding to a disaster caused by an unplanned planet-scale experiment with another only semi-planned planet-scale experiment.
But one has to compare SRM to the plausible alternative: 2-3 degrees of warming, which is what we are expected to hit by 2100, according to the IPCC. Weather patterns are already being hugely disrupted at just over one degree of warming. Extreme weather of all kinds is on the increase. Sea level is already causing chronic flooding around the world, and much worse is set to come. Glaciers that provide drinking water to hundreds of millions are vanishing. Drought and weather disruptions are fueling wars all over the place.
Indeed, 2023 looks likely to smash the record for the hottest year in human history in part because of a decline in sulfur aerosol pollution. As coal and other sources are phased out, we're looking at up to an additional 0.8 degrees of warming compared to 2019.
Moreover, the worst potential scenarios of SRM are less plausible than that of unchecked climate change. Whatever weather disruptions are caused will almost certainly be less bad than what we'd see at three degrees of warming. An ice age is unlikely given how quickly aerosols fall out of the atmosphere.
Most importantly, SRM will not be used as an excuse to not do climate policy, because the energy transition away from fossil fuels is all but on rails at this point. Solar and wind are cheaper than any form of energy in history in big chunks of the globe, and are highly likely to keep getting cheaper for the next decade or two at least. The same is happening with batteries. Commercially viable models of zero-carbon steel, concrete, and industrial heat are coming online. Green hydrogen models for areas that are difficult to decarbonize, like airlines, are being worked out.
Among most important political elites, green energy and technology are now firmly (and correctly) seen as the most key industries for the rest of the century. The US is finally investing heavily into the energy transition. European green investment has accelerated thanks to Putin's invasion of Ukraine, which also demonstrated the national security risk of relying on lunatic dictators for one's energy supply. China is piling into green energy in its habitual gigantic and somewhat ill-planned fashion. Poorer nations are increasingly leapfrogging fossil fuels entirely simply because renewables are cheaper.
The problem is it's just not happening fast enough. Solar and land-based wind investment might actually be on track to meet climate goals, but just about everything else is lagging—the grid upgrades and storage to handle intermittency, getting rid of gas-powered vehicles, green industrial technology, and so on. Offshore wind is running into cost hurdles. Technologies to remove carbon dioxide from the atmosphere look workable (by putting it in concrete, for instance) but most are still in the prototype stage. In short, we'll get there but at about 2-3 degrees rather than 1.5—and that's if we're lucky and don't trip climate feedback loops.
In other words, the point of SRM would be to buy time. A few decades or a century at the outside would likely be enough.
But my main point today is that it isn't up to us in America or Europe. I'm convinced it basically doesn't matter what western environmentalists or indeed western politicians think about SRM. Some country (or group of countries) with serious climate exposure and enough capacity to finance SRM is going to run through the above logic, suffer a serious disaster, and go for it out of desperation. They may already be getting ready.
My money would be on China. Thanks to accelerating sea level rise, it has something like ninety-three million people at risk of annual flooding by 2050, along with most of its core economic production complexes containing trillions upon trillions in infrastructure. It also faces chronic drought threatening water supplies to hundreds of millions more people, serious heat risk, and on and on.
Any functioning country facing the possibility of that kind of damage from a foreign invader would mobilize every last scrap of resources to fight them off. (See: Ukraine.) You think a totalitarian dictatorship is going to let hypothetical worries about global weather patterns stop it from seizing a cheap and easy partial solution to a potentially existential risk? China has already inflicted terrific environmental damage on itself in pursuit of wealth and power; moreover, unlike pollution from coal power plants or mines, the bulk of any side effects from SRM would fall outside of the country.
One could easily tell a similar story about India, Indonesia, Mexico, or some combination of smaller countries. The logic is too compelling to resist.
This is why it's so important to study SRM now. The world needs the best data possible on how it could be done with the least risk, so if and when someone does go for it, they won't have to go on guesses and instinct. Ideally it would be done as part of some internationally coordinated effort, but at least we need a baseline of knowledge.