UK Scientists Want to Block Out The Sun to Fight Climate Change

UK scientists will soon begin outdoor geoengineering tests to block the Sun, supported by a £50 million government fund. The project is led by the Advanced Research and Invention Agency (ARIA) and will be carefully monitored to make sure it’s safe and accurate.

The aim is to gather real-world data on whether these technologies could slow the effects of climate change. A separate £11 million programme will run alongside it. Together, they make the UK one of the top funders of geoengineering research globally.

How Blocking Sunlight Could Help

Geoengineering focuses on methods to reduce the amount of sunlight reaching Earth. A key approach is solar radiation management (SRM), which includes spraying reflective particles into the air or using seawater to make clouds brighter.

Supporters say this could cool the planet temporarily and reduce damage from extreme heat. It would buy time for deeper cuts to carbon emissions. They believe this research is vital as emissions keep rising and temperatures hit new records.

Fears Over Risks and Delayed Action

Despite its promise, SRM is highly controversial. Some experts warn it could disrupt rainfall patterns needed for food. Others worry it might distract from the real goal; ending fossil fuel use.

Professor Mark Symes, who leads the ARIA programme, said the risk of crossing climate tipping points makes this research urgent.

He explained: “The uncomfortable truth is that our current warming trajectory makes a number of such tipping points distinctly possible over the next century. This has driven increased interest in approaches that might actively cool the world in a short timeframe in order to avoid those tipping points.’

“Having spoken to hundreds of researchers, we reached the conclusion that a critical missing part of our understanding was real-world, physical data. These would show us whether any of these potential approaches would actually work and what their effects might be. Modelling and indoor studies are essential as prerequisites, but can only tell us so much.”

He added that no toxic materials will be used. An environmental impact report will be shared before any outdoor testing, and local communities will also be asked for their views. Details of the projects are expected soon.

Some Call it a Dangerous Distraction

Not everyone agrees with the research. Senior scientists have called ARIA’s programme a “dangerous distraction” from cutting emissions. Some even labelled SRM “barking mad” and compared it to “treating cancer with aspirin.”

NERC Launches Separate Geoengineering Study, No Outdoor Testing Involved

Another £10 million geoengineering research project was launched on 3 April by the UK’s National Environment Research Council (NERC). This one won’t involve new outdoor tests. Instead, it will use computer models, past data, and natural events like volcanic eruptions or pollution changes at sea.

Kate Hamer, a director at NERC, said: “Our role is to provide the best possible, robust evidence, but without advocating for [geoengineering] one way or the other.”

Who’s Leading on Geoengineering?

According to Dr Pete Irvine from the University of Chicago, geoengineering research still receives much less funding than wider climate science. Most of it totals only in the low hundreds of millions. The US used to lead, but cuts under President Donald Trump could see the UK take that spot.

“It’s worth stressing that geoengineering is not a substitute for emission cuts,” Irvine said.

Professor Jim Haywood from the University of Exeter, who received NERC funding, said SRM could possibly be scaled up within a decade.

He warned: “At the moment, all of these ideas need to remain on the table, because otherwise climate change in the coming decades could be extremely damaging. Recent global temperatures have been a real wake-up call.”

No Global Rules Yet and Global Talks Are Needed

Right now, there’s no international agreement to manage geoengineering. Experts say a global pause on deployment should be considered until one exists.

Dr Sebastian Eastham from Imperial College London, also funded by NERC, said:

“We know that SRM, or the prospect of SRM, would affect international relations – it’s a serious research question.’

“So part of our project is going to be to convene people from different world regions to understand what might be the consequences.”

He added that some ideas might be ruled out once testing starts:

“I expect we will gather a small amount of observational evidence and it will close the door for some. Then we’ll know we focus our efforts on the areas that are going to be most helpful and least harmful.”