Portal:Climate change/Selected article/13
Pictured left: The albedo of several types of roofs.
Solar radiation modification (SRM) (or solar radiation management or solar geoengineering), are large-scale approaches to limit global warming by increasing the amount of sunlight (solar radiation) that the atmosphere reflects back to space. This would take place by reducing the trapping of outgoing thermal radiation. Among the multiple potential approaches, stratospheric aerosol injection (SAI) is the most-studied, followed by marine cloud brightening (MCB). SRM could be a supplement to climate change mitigation measures, but would not be a substitute for reducing greenhouse gas emissions. SRM methods include mainly atmospheric methods but also ground-based albedo modification (GBAM). Space-based concepts (with space sunshade, space mirrors) also exist but are not currently included in the IPCC Sixth Assessment Report as a relevant option. SRM is a form of climate engineering.
Scientific studies, based on evidence from climate models, have generally shown that some forms of SRM could in theory reduce global warming and therefore many effects of climate change. However, because warming from greenhouse gases and cooling from SRM would operate differently across latitudes and seasons, a world where global warming would be offset by SRM would have a different climate from one where this warming did not occur in the first place. Furthermore, confidence in the current projections of how SRM would affect regional climate and ecosystems is low. SRM would therefore pose environmental risks.
Governing SRM is challenging for multiple reasons, including that several countries would likely be capable of doing it alone. For now, there is no formal international framework designed to regulate SRM, although aspects of existing international law would be applicable. Issues of governance and effectiveness are intertwined, as poorly governed use of SRM might lead to its highly suboptimal implementation. Thus, many questions regarding the acceptable deployment of SRM, or even its research and development, are currently unanswered. In 2022, a dozen academics launched a campaign for national policies of "no public funding, no outdoor experiments, no patents, no deployment, and no support in international institutions... including in assessments by the Intergovernmental Panel on Climate Change." As of December 2024, nearly 540 academics and 60 advocacy organizations have endorsed the proposal. (Full article...) (Full article...)