EGU24-10285, updated on 08 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Assessing GFDL-ESM4.1 Climate Responses to CESM2-WACCM6 Geoengineering Forcing for 2.0°C Warming Target

Shipeng Zhang1,2, Vaishali Naik2, David Paynter2, Simone Tilmes3, and Jasmin John4
Shipeng Zhang et al.
  • 1Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, NJ, USA (
  • 2NOAA Geophysical Fluid Dynamics Laboratory, Princeton, NJ, USA
  • 3Atmospheric Chemistry, Observations, and Modeling Laboratory, National Center of Atmospheric Research, Boulder, CO, USA
  • 4NOAA Atlantic Oceanographic and Meteorological Laboratory, Miami, FL, USA

In this work we apply GFDL Earth System Model (GFDL-ESM4.1) to explore the climate responses to a geoengineering scenario that aims to restrict global warming to 2.0°C above pre-industrial levels (1850–1900) under the CMIP6 overshoot scenario (SSP534-OS) . Simulations of this geoengineering scenario with the CESM Whole Atmosphere Community Climate Model (CESM2-WACCM6) showed nearly unchanged interhemispheric and pole-to-Equator surface temperature gradients relative to present-day conditions around 2020, and reduced global impacts, such as heatwaves, sea ice melting, and large shifts in precipitation patterns (Tilmes et al 2020). Here we implement the identical stratospheric forcing in the GFDL-ESM4.1 model and find excessive global surface cooling and reduced precipitation responses, compared to those projected in CESM2-WACCM. Notably, the Southern Hemisphere experiences more substantial cooling compared to the Northern Hemisphere, accompanied by a north-ward shift in the Intertropical Convergence Zone (ITCZ). These distinct climate responses between GFDL-ESM4.1 and CESM2-WACCM6 can be traced back to their different climate feedback parameters. Furthermore, our analysis reveals that spatially heterogeneous forcing within the geoengineering scenario results in diverse climate feedback parameters even just in one model, through varying surface warming and cooling patterns. This research highlights the importance of considering model structure uncertainties and spatial forcing patterns for a comprehensive evaluation of future scenarios and geoengineering strategies.

How to cite: Zhang, S., Naik, V., Paynter, D., Tilmes, S., and John, J.: Assessing GFDL-ESM4.1 Climate Responses to CESM2-WACCM6 Geoengineering Forcing for 2.0°C Warming Target, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10285,, 2024.