Solar radiation management and its discontents
The Department for Energy Security and Net Zero has put out a policy paper with the government’s views on solar radiation modification technologies (SRM). The bottom line is very blunt:
“The UK Government does not support the deployment of SRM and does not plan to do so. It does not undertake any form of deliberate weather modification.”
Solar radiation modification refers to attempts to reflect more sunlight into space, as a possible means of countering climate change. As the paper sets out, this typically takes two main forms: injecting aerosol particles into clouds over the sea to make them more reflective, or injecting gases into the stratosphere with a similar purpose.
Over the last couple of years the topic has become a magnet for controversies which have often verged into conspiracy theory, not helped by newspaper headlines floating the idea that there is a secret government-funded plan to “dim the sun”. There has been at least one debate in Parliament on the matter, following a petition against geoengineering which received more than 160,000 signatures.
The DESNZ paper argues that there is a “need to understand the risks and impacts of SRM” and that it supports “responsible research that advances scientific understanding of those risks and impacts.”
The paper also gives a summary of UK publicly-funded research into SRM, saying that “most of the research is desk-based with a small number of contained, small-scale field research activities planned.”
Much of the funding to date – as well as much of the media coverage – has involved ARIA’s Exploring Climate Cooling workstream, which will involve five small field trials:
“[The] trials announced will be subject to independent environmental impact and legal assessments, which will be made publicly available before any outdoor experiment takes place. The trials will be limited in size and scale, time-bound, and designed so that effects dissipate within 24 hours or are fully reversible.”
Elsewhere there is a NERC programme which uses only computer modelling, a Met Office programme which uses climate modelling to “explore the implications of SRM deployment,” and a UKRI-/EU-funded project focused on governance principles for SRM research.
DESNZ says that the government’s priority is reducing greenhouse gas emissions, and that research into cooling technologies “does not reduce the urgent need for increased decarbonisation efforts.” It also observes that aircraft contrails are “sometimes mistaken for evidence of weather modification or SRM.”