SAI could act as a temporary measure to reduce radiative forcing by injecting reflective aerosols into the stratosphere to increase Earth's albedo. This method
Two strategies proposed for SRM involve adding dust or chemicals to the Earth's atmosphere to increase the reflected fraction of sunlight (6–8)
In this chapter, we briefly review what is known about proposed solar radiation management (SRM) approaches and related governance and ethical issues and conclude with a discussion of the research needed to better understand SRM. For use of SRM as a potential “backstop option” in the case of an emerging “climate emergency,” improved observations and understanding of climate system thresholds, reversibility, and abrupt changes (see Chapter 6)—for example, observations to let us know when an ice sheet or methane hydrate field may become unstable (e.g., Khvorostyanov et al., 2008; Shakhova et al., 2010)—could inform societal debate and decision making about needs for deployment of a climate intervention system. There is, however, additional research that would be needed to support full evaluation of SRM approaches (just as there is with other options for limiting the magnitude of future climate change), including a variety of social, ecological, and physical sciences (see Chapter 4).
What Kinds of SRM Methods Are Available (and What Do They Involve)? · Space-based Geoengineering · Stratospheric aerosol injection · Surface albedo modification
Solar radiation management (SRM) is a subfield of geoengineering focused on altering the Earth's climate by modifying how sunlight interacts with the planet. Two primary approaches within SRM include albedo modification, which involves increasing the Earth's reflectivity, and solar irradiation mitigation, which focuses on reducing sunlight absorption. The strategy of solar management, in contrast, involves either limiting the amount of sunlight reaching Earth’s surface (solar mitigation) or reflecting some of the sunlight that does reach the surface back into space (albedo modification). One suggested approach to solar radiation management is to increase Earth’s albedo artificially to lower the planet’s temperature by reflecting sunlight into space so that it cannot be absorbed. Furthermore, because such a shield would make no modifications to the atmosphere or to land on Earth, it would not have the possible negative environmental impacts that other approaches to solar radiation management would have.
If you want to do solar radiation management, don't do atmosphere aerosols. Put a sunshade at SEL1 between the Sun and the earth. Make it
**Solar Radiation Modification (SRM) refers to deliberate, large-scale actions intended to decrease global average surface temperatures by increasing the reflection of sunlight away from the Earth.** Proposed SRM methods involve the use of aerosols (small particles) or other materials to increase the reflectivity of the atmosphere, clouds, or Earth’s surface. **Long-term protection of Earth’s climate and oceans requires substantial reductions in emissions and atmospheric concentrations of CO2 and other GHGs. SRM is not considered a substitute for climate mitigation efforts, which include decarbonization and GHG emission cuts.** SRM research is being conducted as a response to growing concerns that the pace of CO2 emissions reductions and CDR technology development is not sufficient to avoid severe impacts of climate change in the next decades. **Many of the processes most important for understanding SRM approaches—such as those that control the formation of clouds and aerosols—are among the most uncertain components of the climate system.** Climate models differ in simulating large-scale aerosol climate effects, including on surface temperatures, due to variations in how aerosol processes, atmospheric transport and mixing, and physics are represented.
The use of sulfate particles (only one of the op tions being considered) could produce acid rain, changes in the chemistry of the atmosphere, and/or depletion of the ozone layer.20 These environmental impacts mean SAI may contribute to greater greenhouse gas retention in the atmo sphere.21 Other outcomes of placing large quantities of sulfur suggested that 1 degree of cooling could be achieved for as little as $20 billion.10 Within the US, this poten tial to achieve quick, cheap cooling impacts has con tributed to major increas es in private investments in research and testing.11 Small-scale outdoor tests of SAI were conducted in the US last year, and more are expected in 2025.12 Figure 1) Potential for SRM to Provide Global Temperature Reduction WHAT ARE THE RISKS OF STRATOSPHERIC AEROSOL INJECTION? The Board notes the many recommendations, including by UNEP and the IPCC, for a globally inclusive, transparent and equitable scientific review pro cess for SRM.39 Such an assess ment would enable a scientifically-informed assessment of the risk trade-offs between climate altering technologies and those of continued global warming at current rates.40 Such a review could also draw on a wide range of perspec tives, including views from global South, developing regions, and Indigenous communities.41 Page 5 of 7 source=chatgpt.com; https://geoengineering.environment.harvard.edu/frank-keutsch-stratospheric-controlled-perturba tion-experiment.