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Geoengineering is politically off-limits—could a Trump presidency change that?

Donald Trump's second presidential term is likely to mean big changes for those of us interested in geoengineering. The term refers to deliberate large-scale manipulation of the climate, perhaps by blocking out some sunlight or directly removing greenhouse gases from the atmosphere. Sometimes called climate engineering, we prefer the term "."

Trump is not the most natural supporter of climate change interventions. He is set to expand oil and gas production hot on the heels of the most terrible wildfires in California. At some point, the US could see hurricanes on scales even more extreme than Katrina or Helene.

Extreme weather will become harder to ignore. Trump could, of course, downplay any link to climate change, but there's a chance this might trigger him to decide emergency action is required and demand to know more about climate engineering options.

After all, Trump is close to certain tech figures who like to global problems. He likes to act fast and is prepared to deal with democratic reactions later. In those circumstances, he might feel that we should do whatever it takes to deploy new climate-saving strategies at speed.

The most effective methods for cooling the planet involve making the Earth more reflective so that it absorbs less heat from the sun. One option, known as , involves spraying sulfur dioxide into the upper atmosphere to mimic the cooling effect of volcanic eruptions.

Clouds could also be altered to become more reflective, an option known as . We can even make ice in the Arctic more reflective by during the winter months so that it lasts longer in the summer, reflecting the sun's heat back into space.

These technologies sound rather fanciful. Some might find them scary. But with the devastation of hurricanes and wildfires, Trump could potentially instruct the US military to give aerosol injection a go. At present, the technology would rely on high-altitude jets to take millions of tons of sulfur dioxide up to the stratosphere above the Arctic, and the US has a lot of these planes.

Alternatively, Trump might take the opposite path and say "this is just part of the natural cycle of weather". Climate-change deniers or those who believe reducing emissions alone will work to hit the 1.5°C or even 2°C targets may be given a platform to convince us all that there is no need for geoengineering.

Geoengineering as an investment

Maybe there is a middle ground. Trump could decide to support geoengineering research to help the insurance industry. If insurance companies will benefit by having fewer storms and fires, then this would be good for the US economy. So perhaps some expenditure on research right now may be a strategic investment.

Behind the scenes are deep discussions on geoengineering governance. There are some who argue that geoengineering is so risky for the climate (what if the world cools too much? are we prepared for any unintended consequences?) that —or at least the research should not be funded by governments.

Others argue that global governance and democratic issues (who is in charge? who gets a say?) need to be addressed . Then there's the "slippery slope" argument, that .

Until now these kinds of arguments have slowed the pace of research, but Trump could say that the current position is wrong, as it holds back our knowledge of something which might help the US economy. If Trump decides to unlock geoengineering as an opportunity, then he may not just provide funding but instruct the national labs to get on with research at pace, thereby accelerating our knowledge of the different options. With good data we can make informed decisions.

How much would this cost? It turns out that geoengineering research is not very expensive and Trump may figure that the potential upside is huge. If he gets excited about it, then geoengineering might suddenly capture the imagination of the US public.

There is increased interest around the world, so the situation in the US is being watched closely. With additional funding and instructions from the new president, geoengineering would soon become established in the mainstream.

Our team at the Center for Climate Repair in Cambridge are not the only ones . This is a hot topic and one which is likely to see significant changes in the coming year.