Abstract
Global mean surface temperature (GMST) is the primary target used to design and compare solar geoengineering simulations, and it is a useful first-order predictor of the climate response. Its limits as a measure of performance, however, remain largely untested. Studies of how solar geoengineering alters climate extremes exist yet remain inadequately explored. We argue that extreme-event metrics should become a formal part of performance assessment, so that success is judged by how interventions alter the risks of floods, heatwaves and droughts especially for climate vulnerable regions.
