Explore technical uncertainties in SAI* research
A dynamic, public, scientifically-grounded assessment of the key technical uncertainties in SAI, focusing on questions related to physical and chemical processes and engineering feasibility.
*Stratospheric Aerosol Injection
26 uncertaintiesLast updated 1mo ago
Uncertainty visualizations
Visualizations
Matrix view
High decision relevance
Medium decision relevance
Volcanic Eruptions During Deployment
Physical Impacts of Deployment Interruption
Stratospheric Ozone
Cirrus Cloud Response
Large-Scale Modes of Atmospheric or Atmosphere-Ocean Variability
Meridional Temperature Gradients
Surface Climate Response to Stratospheric Heating
AMOC
Material Dispersion Technology
Aerosol Spatial Distribution
Extratropical Circulation
Stratospheric Water Vapor
Ice Sheets and Glaciers
Ground Infrastructure
New Aircraft Development
Existing Aircraft Retrofitting
In-Situ Observational Infrastructure
Low decision relevance
Early Deployment Aerosol Observational Requirements
Stratospheric Transport Feedback
Oceanic Carbon Cycle
Surface Air Quality
Low uncertainty
Medium uncertainty
High uncertainty
Aerosol evolution
Aerosol Size Distribution
Impact of aerosol mixing, coagulation, and other sub-grid-scale processes on the radiative forcing of injectionAerosol evolution
Early Deployment Aerosol Observational Requirements
Observational requirements for sufficient monitoring of the stratospheric aerosol distribution during early deploymentAerosol evolution
Aerosol Spatial Distribution
Spatial distribution of aerosols due to stratospheric transport and mixingClimate response
Volcanic Eruptions During Deployment
Changes in how a sulfur-rich volcanic eruption impacts the climate during SAI compared to a climate without interventionClimate response
Physical Impacts of Deployment Interruption
Physical impacts of deployment interruption — specifically the climate impacts associated with a short, sharp rise in temperaturesClimate response
Stratospheric Ozone
Impact on stratospheric ozone due to changes in physical and chemical processesClimate response
Stratospheric Transport Feedback
Effect of stratospheric heating due to aerosol LW absorption on stratospheric transportClimate response
Cirrus Cloud Response
Changes to cirrus clouds due to SAI, such as via changes in vertical temperature gradientClimate response
Large-Scale Modes of Atmospheric or Atmosphere-Ocean Variability
Change in mean-state or variance of large-scale modes of atmospheric or atmosphere-ocean variability — such as the ENSO, NAO, PDO, and SAMClimate response
Meridional Temperature Gradients
Impact of meridional profile of AOD on changes in meridional temperature gradientsClimate response
Surface Climate Response to Stratospheric Heating
Impacts of Stratospheric Heating on Surface Climate Processes Such as the North Atlantic Oscillation, QBO and Polar VorticesClimate response
Tropical Circulation
Changes in tropical circulation — including monsoons, the MJO and the Walker circulationClimate response
Extratropical Circulation
Changes in extratropical circulation — including the polar vortices, jet streams, and storm tracksClimate response
AMOC
Changes in AMOC — along with other ocean circulations and their patterns and strengthsClimate response
Stratospheric Water Vapor
Impact of increased aerosol SAD-induced stratospheric heating on eventual increased water vapor in the stratosphereEarth system response
Oceanic Carbon Cycle
Impact on oceanic carbon cycle, due to changes in biogeochemistry, ocean circulation, and other driversEarth system response
Terrestrial Carbon Cycle
Impact on terrestrial carbon cycle of changes in NPP, carbon storage, etc.Earth system response
Terrestrial Vegetation
Terrestrial vegetation (including crop) response to the combined changes in CO2, temperature, water availability, direct-diffuse light ratios, etc.Earth system response
Ice Sheets and Glaciers
Land ice response to SAI, including temperature-driven and circulation-driven impacts, and marine ice-sheet instability (tipping)Earth system response
Surface Air Quality
Changes in PM2.5 and surface ozone and associated imapct on human healthEngineering
Ground Infrastructure
Feasibility of and timeline to develop necessary ground infrastructure to start deployment (at ~1Mt/yr)Engineering
Satellite Observational Infrastructure
Feasibility of and timeline to bring sufficient satellite observational infrastructure onlineEngineering
New Aircraft Development
Feasibility of and timeline to develop and build aircraft which can deploy material at 20kmEngineering
Existing Aircraft Retrofitting
Feasibility of and timeline to retrofit existing aircraft for low-altitude (15km), high-latitude (>60°N/S) (HiLLA) deploymentEngineering
Material Dispersion Technology
Feasibility of and timeline to research, develop, and build material dispersement technology, including but not limited to nozzles and in-flight storageEngineering