Geoengineering: the scientists who argue modifying the climate could buy the world time – podcast

With global temperature records broken for months on end, and the severity of extreme weather events routinely attributed to climate change, you might think any technological developments with the potential to stop global warming would be welcomed the world over.

But the pursuit of geoengineering – attempts to modify the climate for the purposes of reversing climate change – is a hugely divisive issue. So divisive, that we’ve decided to explore the debate on geoengineering in two episodes of The Conversation Weekly podcast.

In this first episode, we talk to scientists working on different potential geoengineering technologies who argue the case for researching these interventions. In our second episode, we speak to researchers mounting a campaign against a particular type of geoengineering called solar radiation management.

For Hugh Hunt, geoengineering is a “band aid, this thing we need to do to buy us time”. Hunt is deputy director at the Centre for Climate Repair at the University of Cambridge in the UK, led by his colleague Shuan Fitzgerald. They’re leading a team of scientists exploring potential engineering strategies to reduce global warming.

In arguing the case for climate repair, Hunt points to a graph first set out by scientist John Shepherd in 2010. Now referred to simply as the “napkin diagram”, it suggests that aggressive emission reductions, combined with large scale carbon dioxide removal could take temperatures back below 1.5 degrees above pre-industrial levels by around 2300.

Once we get our emissions cut and we get our carbon dioxide removal that’s great, but that’s not for another 150 years and the Arctic ice will have melted and the Antarctic glaciers will be irreversibly damaged.

Advocates of geoengineering believe technological fixes can help in the meantime, including through technologies aimed at reflecting more sunlight back into space to help cool the Earth, known as solar radiation management.

At Cambridge, Fitzgerald and Hunt are also involved in a number of research projects assessing various potential technological interventions. One, explains Fitzgerald, is how to increase ice cover in the Arctic.

We are looking at whether we can get more sea ice in the Arctic, especially in the Arctic summer … and the way to do that is to see whether you can grow more of the stuff in the Arctic winter.

This involves pumping sea water on top of the sea ice in various volumes to assess how much this helps to thicken the ice and in what ways. The centre is collaborating with a UK-based company called Real Ice, which began a pilot study in northern Canada in early 2024. The team pumped sea water over about 4,000 square meters of snow. Four months later, in May, they returned to measure the depth of the sea ice in that area and in a control area.

What they found was that the ice depth was 50cm greater in the area where they had flooded the snow compared with the control region.

More experiments are being planned for the coming Arctic winter to test various permutations of this ice flooding technique and their effects on the sea ice.

Tricky calculus

Even among scientists actively researching geoengineering, there is debate about its potential risks and benefits. Ben Kravitz, assistant professor of Earth and atmospheric sciences at Indiana University in the US, spends much of his time modelling the potential effects of solar geoengineering. This includes a technique called stratospheric aerosol injection, which involves releasing particles of sulphur dioxide high up in the stratosphere to reflect sunlight away from Earth.

From all of the climate modelling and natural science research that we’ve done, the conclusion is … it’s not a replacement for reducing our emissions, but by and large for most people, a little bit of geoengineering is helpful.

However, Kravitz says when you get into the social implications of geoengineering “things start to get a lot more messy”. He’s looked into the various national security and geopolitical risks involved in solar geoengineering, but he’s also worried about what deploying these technologies might mean for food security and people’s livelihoods.

It’s really important to remember that climate change is causing a lot of risks too. It is entirely possible that geoengineering would alleviate some of those risks, and also possibly introduce new risks. That’s the sort of calculus that we really need to get a handle on if people are going to make an informed decision about whether we should do this.

Listen to the full episode on The Conversation Weekly podcast, which also features Stacy Morford, the environment and climate editor at The Conversation in the US. The second part, featuring interviews with solar geoengineering critics Chukwumerije Okereke and Aarti Gupta, will be released on August 30.

A transcript of this episode is available on Apple Podcasts.

This episode of The Conversation Weekly was written and produced by Katie Flood with assistance from Mend Mariwany. Sound design was by Eloise Stevens, and our theme music is by Neeta Sarl. Gemma Ware is the executive producer.

Newsclips in this episode from DW News, BBC News, Al Jazeera English and CBS News.

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