Theme: 2. Mitigation

Topic Area: 2a. Market Mechanisms (Technology & Process) for Carbon Neutrality

Background/Objectives:

The growing severity of the impacts of anthropogenic climate change, particularly those resulting from increased extreme weather events and large-scale wildfires, has led to calls for serious consideration of multiple approaches to intentional climate intervention, or geoengineering. In addition to attempts at carbon dioxide removal (CDR) through direct air capture and other means, achieving net-zero emissions through enhanced biospheric carbon uptake and carbon sequestration, and transitioning to renewable and hydrogen power sources, there is growing interest in ways to reduce or stabilize global surface temperatures. Stratospheric aerosol intervention (SAI), the direct injection of sulfur into the lower stratosphere, is considered the most feasible option to have a significant impact on surface temperature.

Approach/Activities:

In our research, we quantify the benefits and risks of SAI by applying it under several CMIP6-endorsed future scenarios in DOE’s Energy Exascale Earth System Model (E3SM) and comparing the results to CMIP6 model outputs. To dynamically redistribute the injected sulfate aerosol and capture the stratospheric chemistry, we implemented the Whole Atmosphere Community Climate Model (WACCM) Troposphere, Stratosphere, and Lower Thermosphere (TSMLT) chemistry mechanism into E3SM.

Results/Lessons Learned:

In the presentation, we will show our assessment on the impact of SAI-induced reductions in radiative forcing on global and regional climate, atmospheric dynamics and aerosol-cloud interactions, and the strength of land and ocean carbon sinks under scenarios involving changing CO₂ levels and CDR.

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Salil Mahajan