Scientists propose guidelines to assess solar geoengineering research

Scientists have proposed a set of guidelines to assess the feasibility of solar geoengineering scenarios (Oxford Open Clim. Change 2024, DOI: 10.1093/oxfclm/kgae010). With the guidelines, the researchers aim to give scientists and policymakers a way to evaluate the risks and benefits of injecting sulfur particles into the air to mitigate climate change—a process known as stratospheric aerosol injection (SAI).

Solar geoengineering research has been taking place for years, but no one has created a full picture of whether the approaches being studied are technologically feasible or if they could have unwanted side effects.

The goal is to use the guidelines “to assess the current state of research” in a way that mirrors the work of groups like the World Meteorological Organization (WMO), says Simone Tilmes, a project scientist at the US National Center for Atmospheric Research and coauthor of the paper.

The WMO brings together scientists every 4 years to evaluate the health of the ozone layer. “That type of model works really well for informing policymakers about the health of the ozone layer and what regulation needs to be put in place,” Tilmes says. “We need something similar, but in a bigger context, for SAI or climate intervention strategies.”

The guidelines include eight criteria to examine ascenario’s technical and design requirements, impact on human and natural systems, and societal effects. “We’re not advocating deployment. We’re advocating knowledge accumulation,” says coauthor Karen Rosenlof, a senior scientist for climate and climate change at the US National Oceanic and Atmospheric Administration.

Lili Fuhr, director of the fossil economy program at the Center for International Environmental Law, says the guidelines appear well intentioned. “However, they ultimately fall short of addressing the fundamental risks and ethical concerns associated with” solar geoengineering, she says.

The researchers did consider societal risks, but Tilmes explains that the proposed guidelines include only high-level criteria that need further refinement.