“Cooling credits” are not a viable climate solution

• Published in: Climatic change Vol. 176; no. 7; p. 96
• Main Authors: Diamond, Michael S., Wanser, Kelly, Boucher, Olivier
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.07.2023; Springer Nature B.V
• Subjects: Aerosols; altitude; Atmosphere; Atmospheric Sciences; Carbon offsets; Climate; Climate change; Climate Change/Climate Change Impacts; Cooling; Earth and Environmental Science; Earth atmosphere; Earth Sciences; Environmental impact; Environmental risk; Essay; Gases; Global warming; Greenhouse effect; Greenhouse gases; greenhouses; Intervention; liquids; Low altitude; Monitoring systems; risk; solar radiation; Sunlight; Upper atmosphere; Stratospheric aerosol injection; Geoengineering; Climate risk; Solar radiation modification; Marine cloud brightening; Climate intervention
• ISSN: 0165-0009; 1573-1480
• DOI: 10.1007/s10584-023-03561-w

As the world struggles to limit warming to 1.5 or 2 °C below pre-industrial temperatures, research into solar climate interventions that could temporarily offset some amount of greenhouse gas-driven global warming by reflecting more sunlight back out to space has gained prominence. These solar climate intervention techniques would aim to cool the Earth by injecting aerosols (tiny liquid or solid particles suspended in the atmosphere) into the upper atmosphere or into low-altitude marine clouds. In a new development, “cooling credits” are now being marketed that claim to offset a certain amount of greenhouse gas warming with aerosol-based cooling. The science of solar climate intervention is currently too uncertain and the quantification of effects insufficient for any such claims to be credible in the near term. More fundamentally, however, the environmental impacts of greenhouse gases and aerosols are too different for such credits to be an appropriate instrument for reducing climate risk even if scientific uncertainties were narrowed and robust monitoring systems put in place. While some form of commercial mechanism for solar climate intervention implementation, in the event it is used, is likely, “cooling credits” are unlikely to be a viable climate solution, either now or in the future.