Political economy suggests that geoengineering is likely to be used

A QUARTER-CENTURY has passed since the first global climate-change treaty, the UN Framework Convention on Climate Change. Humanity’s record of following through on its climate promises is dismal. The concentration of carbon dioxide in the atmosphere has risen by 15% since 1994. The average global temperature, relative to the norm for 1951-80, has gone up by about 0.5°C over that period. And in 2018 annual emissions reached their highest level ever. To have a good chance of stopping global temperatures rising more than 1.5°C relative to the pre-industrial norm, by 2030 annual greenhouse-gas emissions must fall by almost half, relative to levels in 2010, according to the Intergovernmental Panel on Climate Change. They almost certainly will not.

A much warmer and more hostile climate might yet be avoided, however, through geoengineering: tinkering with climate processes to reduce the global temperature. (The possibilities are described at length in “The Planet Remade” by Oliver Morton, a journalist on this newspaper.) The longer climate targets are missed, the more likely geoengineering is to be used—and the more urgent it is that governments understand its tricky political economy.

Earth is warming because carbon dioxide and other greenhouse gases are accumulating in the atmosphere, shifting the balance of energy arriving from the sun and flowing back out into space. For a generation, the main political response has been to set targets for reducing emissions, in the hope that new laws and technologies will see them met. But decarbonising an industrialised economy is monumentally hard. America’s Energy Information Agency reckons that the share of renewables in the global energy mix will touch 18% of the total by 2050, up from just over 13% now. Vast systems of fossil-fuel infrastructure—tens of thousands of power stations, a billion vehicles—remain in place. The most ambitious decarbonisation programmes, such as Germany’s Energiewende, have made progress. But developed economies will meet their climate goals only if they all cut emissions faster than the peak rate Germany had managed as of 2017, for decades. And developing economies must either perform the unprecedented feat of growing without fossil fuels, or stop growing altogether.

Such costs might be borne, were it not for the dreadful political economy of climate-change mitigation. It is the stock of carbon in the atmosphere that determines how much warming there will be, not the flow. Warming today is the consequence of past emissions. Correspondingly, cuts are irksome when they are made but bring benefits only in the future. Furthermore, the benefits of reducing emissions are spread globally whereas the costs—of new power plants, vehicles and so on—are local. That creates an incentive to free-ride: to continue using dirty fuels while hoping other countries’ efforts will avert future disaster. To decarbonise knowing that the benefits will take decades to arrive, and even then only if every other big country also acts, is a lot to ask of a political system.

Solar geoengineering is different. Big volcanic eruptions cool the planet by releasing plumes of sulphur dioxide into the upper atmosphere. These eventually turn into an aerosol mist of reflective sulphate particles, which block a little of the sun’s energy from making its way to Earth’s surface. Humans could try something similar to offset the warming effect of greenhouse-gas emissions. Building and maintaining a system for pumping out reflective particles would be expensive, but much less so than rebuilding the world’s energy infrastructure. If successful, it would begin to offset the greenhouse effect immediately. And a single determined country could go it alone. America could potentially launch a programme at a cost less than NASA’s annual budget, and—if all goes to plan—stop warming in its tracks. At some point, a large country may reckon that the costs to it alone of warming are higher than the costs to it alone of a geoengineering programme. If political economy makes cutting emissions near-impossible, it seems to make geoengineering something like inevitable.

Look closer, however, and solar geoengineering would be anything but politically straightforward. It is not a solution to climate change, for one thing, but a stopgap. Until emissions are reduced it must continue, or sudden, catastrophic warming will result. Deflecting sunlight does nothing to fix other emission-linked problems, such as the oceans becoming more acidic. The effects of cooling, like warming, would be global, and sure to provoke an international response. Some countries might object to unilateral tinkering with the climate. Others might fight over how much cooling should take place. The effects of warming and cooling (as well as shifts in things like precipitation) could be geographically uneven in politically explosive ways. Some climate models suggest that geoengineering that left China at a comfortable temperature could cool India to below the level of the late 20th century.

The winds of winter

Perhaps a collective approach to geoengineering could be negotiated. The possibility of unilateral action might focus minds. Relative to dramatic, binding emission cuts, it would be cheaper and more immediately effective, and so perhaps easier to agree on. A more leisurely decarbonisation could then take place.

Still, any agreement would be difficult. The longer talks are put off the more likely unilateral action becomes, perhaps in response to a climate emergency. Some powerful countries would no doubt see climatic changes imposed on them as a security threat. Should one of them develop a geoengineering capacity, others might feel pressed to as well. Countries could seek to move first rather than risk seeing a rival reshape the global climate to its liking, and hang all others—or see everyone hang back, with the result being dangerous warming for all. More likely, geoengineering would not relieve humanity of the need to co-operate globally. Having embarked on the great experiment of industrialisation, countries must either work together or burn together.