SRM & Security

The document explores how sunlight reflection methods (SRM), such as stratospheric aerosol injection (SAI) and marine cloud brightening (MCB), interact with global security. While SRM could mitigate climate-driven security risks by lowering temperatures, it may introduce new tensions regarding its use and outcomes. The briefing distinguishes SRM from cloud seeding, noting that while the latter has a history of weaponisation (e.g., Operation Popeye), SAI and MCB are too imprecise for direct weapon use but could still be used for general disruption. It argues that large-scale deployment would be difficult to hide due to detectable infrastructure and atmospheric effects. Two hypothetical scenarios are presented: one involving military tensions in the Arctic over an SAI programme and another involving accusations of drought in South Asia. The authors recommend building trust, transparency, and using scenario gaming to manage these security challenges.

• Sunlight reflection methods (SRM) are distinguished from cloud seeding by their scale and intent. Cloud seeding is used in over 50 countries for local precipitation or hail reduction. In contrast, Marine Cloud Brightening (MCB) aims for regional cooling with potential global impacts, and Stratospheric Aerosol Injection (SAI) would produce a "global cooling effect, altering the climate around the world."
• While cloud seeding was used by the US military during the Vietnam War in Operation Popeye, leading to the ENMOD treaty ban, MCB and SAI are "not suited to being used as direct weapons" because they are too imprecise to target specific areas. However, they could still be used as "a tool of general disruption" or deployed without regard for neighbours, creating security challenges.
• Large-scale SAI and MCB deployment would be difficult to conduct in secret. SAI would be detectable through "new types of planes flying the same unusual sorties" and the "millions of tonnes of sulphate particles" required, which satellites would monitor. MCB would be visible via "fleets of ships patrolling patches of the open ocean."
• SRM deployment could create new geopolitical frictions even if it reduces overall climate risks. Hypothetical scenarios illustrate risks such as military encroachment in the Arctic leading to objections from Russia, or nuclear-armed powers in South Asia demanding compensation and cessation of SAI after attributing an "unprecedented drought" to the programme.

APA

The Council on Strategic Risks (2026). SRM & Security. https://councilonstrategicrisks.org/wp-content/uploads/2026/02/SRM360-SECURITY-PRIMER.pdf

Chicago

The Council on Strategic Risks. SRM & Security. 2026. https://councilonstrategicrisks.org/wp-content/uploads/2026/02/SRM360-SECURITY-PRIMER.pdf.

Wikipedia

{{cite report |author=The Council on Strategic Risks |title=SRM & Security |date=February 2026 |url=https://councilonstrategicrisks.org/wp-content/uploads/2026/02/SRM360-SECURITY-PRIMER.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{thecouncilonstrategicrisks2026srm, author = {{The Council on Strategic Risks}}, title = {{SRM \& Security}}, institution = {The Council on Strategic Risks}, year = {2026}, month = feb, url = {https://councilonstrategicrisks.org/wp-content/uploads/2026/02/SRM360-SECURITY-PRIMER.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }