Why we urgently need to talk about geoengineering

We are heading towards a future that is so much hotter we won’t just be able to carry on as normal. Along the way, there is a very high risk of triggering “tipping points” that would make the climate chaos dramatically worse. Given our failure to cut carbon emissions, the appeal of geoengineering to cool the planet is growing – but is it the right thing to do?

As we report in “Geoengineering could avoid climate tipping points, but not if we delay”, some researchers are coming round to the idea that pumping sunlight-reflecting aerosols into the stratosphere could prevent tipping points like the shutdown of vital ocean currents. But the risks of geoengineering are huge.

For starters, there is no prospect of getting international agreement on this soon, but if one country went it alone, things could go very wrong, shifting rainfall around the world, for example. And if one nation felt it were being harmed by another’s geoengineering, we could end up in a climate war in which geoengineering is used as a weapon.

Even if there were agreement, things would be far from straightforward. Done wrong, geoengineering could make things worse, not better. There has been far too little computer modelling and real-world testing of any geoengineering ideas for us to have any confidence that they will pan out as intended.

The thing is, the clock is ticking. The sooner we start geoengineering, the better the chance of averting dangerous tipping points. It is an option that we should at least explore.

Still, many scientists are opposed to even doing research on geoengineering. One fear is that it will be used as an excuse to not cut carbon dioxide emissions. Yet that argument holds less sway in a world where US President Donald Trump is reversing climate action without bothering with an excuse of any kind (see “What will be the climate fallout from Trump’s ‘big beautiful bill’?”).

Geoengineering may be a terrible idea – but we won’t know that unless we carry out significantly more research. The time to do that is now, before we are forced to take drastic action without robust science to guide us.