https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL087929
Forcing Dependence of Atmospheric Lapse Rate Changes Dominates Residual Polar Warming in Solar Radiation Management Climate Scenarios Matthew Henry Timothy M. Merlis First published: 19 July 2020 https://doi.org/10.1029/2020GL087929 About Sections Share on Abstract Simulations of solar radiation management (SRM) geoengineering using comprehensive general circulation models show a residual surface warming at high latitudes. Previous work attributes this to the difference in forcing structure between the increase in greenhouse gases and decrease in insolation, but this neglects the role of the induced reduction in atmospheric energy transport. Here we show that the difference in vertical structure of temperature change between increasing CO2, decreasing insolation, and decreasing atmospheric energy transport is the dominant reason for the residual near‐surface warming at high latitudes. A single‐column model (SCM) is used to decompose the high‐latitude temperature change and shows the importance of the enhanced near‐surface warming from the CO2 increase in explaining the residual polar warming. This suite of models invites caution when attributing high‐latitude surface temperature changes to the lapse rate feedback, as various forcings and nonlocal processes affect the vertical structure of temperature change differently. Plain Language Summary Solar radiation management (SRM) geoengineering has been proposed as a way of counteracting the warming effects of increasing greenhouse gases by reflecting solar radiation. When the carbon dioxide concentration (CO2) is quadrupled and the solar constant is reduced in climate models to reach zero global mean surface temperature change, there is still residual warming in polar regions. Previous analyses suggested that it was caused by the latitudinal difference in forcing between the CO2 increase and insolation reduction. This work shows the importance of the differences in vertical structure of atmospheric temperature change between the CO2 increase and solar radiation reduction in explaining this residual polar warming. This underlines the importance of considering the vertical structure of temperature change caused by a given forcing when trying to understand what shapes the pattern of surface temperature change. -- 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/CAJ3C-06asK4ZRFz7CiMpufwUmxRuwQ4iuYVPOuhj_9HoADTL2g%40mail.gmail.com.
