What’s Needed for Decisionmaking on Atmospheric Experiments

The Union of Concerned Scientists (UCS) emphasizes that while solar geoengineering (SG) cannot substitute for emissions reductions, the potential for atmospheric experiments requires robust, transparent, and inclusive public engagement. The brief outlines the risks of SG, such as 'termination shock' and 'moral hazard,' and provides a framework for engagement levels—ranging from informing to empowering—to ensure that research is conducted with societal legitimacy and ethical oversight.

• Solar geoengineering (SG) is not a substitute for reducing emissions because it does not address the primary cause of climate change—heat-trapping gas emissions—and fails to stop ocean acidification or the negative effects of fossil fuel use on terrestrial ecosystems.
• The two primary SG approaches under consideration are stratospheric aerosol injection (SAI), which mimics volcanic eruptions to cool the planet globally, and marine cloud brightening (MCB), which uses sea salt to create regional-scale cooling.
• SG technologies carry significant risks, including 'moral hazard' (reducing motivation to cut emissions), 'slippery slope' (research leading inadvertently to deployment), and 'termination shock' (rapid temperature spikes if SAI is abruptly stopped).
• Current SG research has largely occurred without meaningful public input, particularly for civil society and governments in developing countries, creating a need for a more inclusive and deliberative platform for decisionmaking.
• UCS recommends that small-scale outdoor experiments must meet specific criteria: they require legitimate governance mechanisms, negligible environmental, social, and legal risks, and meaningful engagement with publics both within and beyond the experimental area.
• Adapting the US EPA Public Participation Guide, the document proposes five levels of engagement for SG research: Inform (providing facts), Consult (understanding preferences), Involve (seeking nonbinding recommendations), Collaborate (building consensus), and Empower (giving decisionmaking authority to the public).
• The brief highlights specific proposed experiments, including Harvard's SCoPEx (a small-scale SAI test using calcium carbonate) and MCB tests for Australia's Great Barrier Reef, noting that the latter has proceeded with government funding but without public and stakeholder engagement.

APA

Union of Concerned Scientists (2020). What’s Needed for Decisionmaking on Atmospheric Experiments. https://www.ucs.org/sites/default/files/2020-06/Solar%20Geo_WEB_New.pdf

Chicago

Union of Concerned Scientists. What’s Needed for Decisionmaking on Atmospheric Experiments. 2020. https://www.ucs.org/sites/default/files/2020-06/Solar%20Geo_WEB_New.pdf.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=What’s Needed for Decisionmaking on Atmospheric Experiments |date=June 2020 |url=https://www.ucs.org/sites/default/files/2020-06/Solar%20Geo_WEB_New.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientists2020whats, author = {{Union of Concerned Scientists}}, title = {{What’s Needed for Decisionmaking on Atmospheric Experiments}}, institution = {Union of Concerned Scientists}, year = {2020}, month = jun, url = {https://www.ucs.org/sites/default/files/2020-06/Solar%20Geo_WEB_New.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }