The effects of climate change are getting more and more severe.

Some experts argue that it’s time to deploy some form of ambitious solar geoengineering project to buy ourselves time to get the climate back under control. But solar geoengineering technology is still largely untested, and there’s a lot of uncertainty about whether it will work, or how it would be managed. Something could go wrong.

We could try solar geoengineering now, or spend a few more years talking about it first, trying to reach international consensus about how we should go about it.

Should we try a last-ditch geoengineering solution?

Solar geoengineering is a proposed group of technologies that aim to reflect more sunlight away from the earth to cool the climate. These include ideas like injecting sulphur aerosols into the stratosphere, brightening the clouds above the ocean, or even deploying space mirrors. None of these technologies are ready for deployment (in 2021). Research suggests that solar geoengineering could reduce temperatures, but it could also introduce some big new risks, like disrupting rainfall in major food-producing regions. Solar geoengineering has been called a stopgap measure because it does not reduce greenhouse gas emissions, the underlying driver of climate change. It treats the symptoms rather than curing the underlying condition. Solar geoengineering is highly controversial, with some people arguing more research should be done on these technologies, and others saying that tampering even more with our climate system is too risky.