A new global map of potential surface-reflected solar radiation
Abstract
Solar radiation modification methods have been proposed for interventions located at Earth's surface, in the atmosphere, and at the L1 point in space. Space-based and atmospheric reflectivity interventions have captured the attention of researchers, media, and policymakers, whereas surface-based reflectivity interventions have gotten short shrift due to limited land area and atmospheric attenuation. A National Academies of Sciences, Engineering, and Medicine 2021 report featuring recommendations for solar geoengineering research and research governance left out surface albedo modification entirely. Global-mean estimates of surface-reflectivity potential have been published, however a global map is lacking. Here we show a map of surface-reflected outgoing solar radiation potential using a simple radiative transfer model that accounts for atmospheric absorption, transmission, and reflection. The map reveals land areas where annual-mean surface-reflected outgoing solar radiation (i.e. outsolation) could be increased above 200 Wm-2, like subtropical deserts, and ocean areas where annual-mean surface-reflected outsolation could be increased above 150 Wm-2, like sub-equatorial oceans. Whereas land areas have higher potential on average, the potential over ocean areas is larger relative to the amount that the surface currently reflects. The results are robust to the choice of input data, including reanalysis and satellite-based solar fluxes. Our approach builds upon previous results that explored particular surface-based reflectivity interventions like urban, crop, and desert brightening. The results confirm that surface albedo enhancement can contribute to negative radiative forcing as part of a broader set of climate intervention strategies and suggest specific geographies with particularly high potential. Future research could extend our methods to consider seasonal variations or apply them to estimate the impact of local albedo enhancements like reflective roofs, shade structures, water covers, and cover crops.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMGC22E0660S