Harvard scientists announced that they were using geoengineering to dim the sun

A $100 million geoengineering research programme to ‘dim the sun’ has been proposed.

In a new report, the National Academies of Sciences, Engineering, and Medicine, said that the US should dedicate between $100m (£73m) to $200m over five years to better understand the feasibility of interventions to dim the sun in order to fight climate change.

It recommended interventions designed to cool Earth by adding small reflective particles to the upper atmosphere, by increasing reflective cloud cover in the lower atmosphere, or by thinning high-altitude clouds that can absorb heat.

It argued that the impacts of global heating could be so great that every option to limit these must be explored.

The report claimed that outdoor experiments should be allowed only if they provide critical knowledge that cannot be obtained by other means. 

However, in a separate report the researchers argued that while strategies have the potential to reduce global temperatures and thereby ameliorate some of the risks posed by climate change, they could also introduce an array of unknown or negative consequences.

Prof Marcia McNutt, the president of the academy, stated: “Given the urgency of the climate crisis, solar geoengineering needs to be studied further. But just as with advances in fields such as artificial intelligence or gene editing, science needs to engage the public to ask not just can we, but should we?

“The US solar geoengineering research programme should be all about helping society make more informed decisions.”

However, critics of the proposal have warned that solar geoengineering could damage crops, and would need to be maintained to avoid temperature spikes unless carbon emissions fall rapidly.

The academy said the programme should include scientific research on the possible climate outcomes of geoengineering and its impacts on ecosystems and society. 

Silvia Ribeiro, Latin America director for the ETC campaign group, added: “The report asking for more research into a technology we don’t want is essentially flawed.”

However, efforts to use cloud seeding technology have already been deployed to block the sun. David Keith from Harvard University claimed that they would be spraying sun-reflecting chemical particles into the atmosphere to artificially cool the planet, using a balloon flying 80,000 feet over Fort Sumner, New Mexico. 

At the time of the experiment, Keith said: “The objective is not to alter the climate, but simply to probe the processes at a micro-scale. The direct risk is very small.”

Keith owns a multimillion-dollar geoengineering research centre provided by Microsoft founder Bill Gates. The research centre previously commissioned a study by a US aerospace company that made the case for the feasibility of large-scale deployment of solar geoengineering technologies.