Simulation of Aerosol Distributions Before and During a Geoengineering

Simulation of Aerosol Distributions Before and During a Geoengineering

Sulfate Aerosol distribution before and during the first 5 years of an application of stratospheric aerosol geoengineering (using feedback) simulated by a state-of-the-art coupled earth system model. Colors represent aerosol radius and do not illustrate the transparency of such an aerosol cloud.

Geoengineering, often using stratospheric sulfate aerosols, is discussed as a potential means of deliberately offsetting some of the effects of climate change, such as rising temperatures. Many previous simulations have looked at specific scenarios of geoengineering and analyzed the resulting climate effects. Here we turn the question around by choosing specific climate objectives and evaluating whether and how one can meet those objectives in the presence of uncertainty.

In particular, we show the results of meeting three simultaneous surface temperature objectives (global mean, inter-hemispheric, and equator-to-pole gradient).

The model uses feedback on the “observed” model state and adjusts the amount of sulfate aerosol injection in the stratosphere at each of four latitudes every year, depending on whether more or less is needed to keep the climate at 2020 conditions with increasing greenhouse gas emissions.

While warming in the RCP8.5 simulation (a scenario with no climate policy) continues unabated, global patterns of warming are suppressed in the geoengineering (feedback) simulation.

This simulation was produced with CESM1(WACCM), a version of the Community Earth System Model version 1 (CESM1) with the Whole Atmosphere Community Climate Model (WACCM) as its atmospheric component.

This state-of-the-art atmosphere-ocean earth system model, developed by the National Center for Atmospheric Research (NCAR), contains significant advances in representations of chemistry, stratospheric dynamics, and aerosol microphysics.

https://www.youtube.com/watch?app=desktop&v=DC6Lkb7VbFU