*This item and others will be in the monthly “Solar Geoengineering Updates Substack” newsletter:* https://solargeoengineeringupdates.substack.com/ -----------------------------------------------------------------
https://www.science.org/doi/full/10.1126/sciadv.adh7716 *Authors* TIANLE YUAN , HUA SONG, ROBERT WOOD, LAZAROS OREOPOULOS, STEVEN PLATNICK, CHENXI WANG, HONGBIN YU, KERRY MEYER, AND ERIC WILCOX *8 November 2023* DOI: 10.1126/sciadv.adh7716 Abstract Aerosols cool Earth’s climate indirectly by increasing low cloud brightness and their coverage (Cf), constituting the aerosol indirect forcing (AIF). The forcing partially offsets the greenhouse warming and positively correlates with the climate sensitivity. However, it remains highly uncertain. Here, we show direct observational evidence for strong forcing from Cf adjustment to increased aerosols and weak forcing from cloud liquid water path adjustment. We estimate that the Cf adjustment drives between 52% and 300% of additional forcing to the Twomey effect over the ocean and a total AIF of −1.1 ± 0.8 W m−2. The Cf adjustment follows a power law as a function of background cloud droplet number concentration, *Nd *. It thus depends on time and location and is stronger when *Nd *is low. Cf only increases substantially when background clouds start to drizzle, suggesting a role for aerosol-precipitation interactions. Our findings highlight the Cf adjustment as the key process for reducing the uncertainty of AIF and thus future climate projections. *Source: Science Advances* -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/CAHJsh99H_ZAZuJyavwh5YGGidyRCyURxn3aQjKcPAC5Kdi-WbQ%40mail.gmail.com.
