In active developmentChangelogFeedback
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
23 uncertaintiesLast updated 1mo ago
Uncertainty visualizations
Visualizations
Matrix view
High decision relevance
Medium decision relevance
Volcanic Eruptions During Deployment
Stratospheric Ozone
Cirrus Cloud Response
Large-Scale Modes of Atmospheric or Atmosphere-Ocean Variability
Surface Climate Response to Stratospheric Heating
Existing Aircraft Retrofitting
Material Dispersion Technology
Stratospheric Transport of Aerosols
Extratropical Circulation
Atlantic Meridional Overturning Circulation
Stratospheric Water Vapor
Ice Sheets and Glaciers
Ground Infrastructure
New Aircraft Development
Climate Response Monitoring
Low decision relevance
Low uncertainty
Medium uncertainty
High uncertainty
Research priority
- Lower
- Medium
- High
- Critical
Aerosol evolution
Aerosol Size Distribution
Impact of aerosol mixing, coagulation, and other sub-grid-scale processes on the radiative forcing of injection- Uncertainty
- Medium
- Decision relevance
- High
- Resolvability scale
- Small-scale testing
Aerosol evolution
Stratospheric Transport of Aerosols
Spatial distribution of aerosols due to stratospheric transport and mixing- Uncertainty
- Medium
- Decision relevance
- Medium
- Resolvability scale
- Small-scale testing
Climate response
Volcanic Eruptions During Deployment
Changes in how a sulfur-rich volcanic eruption impacts the climate during SAI compared to a climate without intervention- Uncertainty
- Low
- Decision relevance
- Medium
- Resolvability scale
- Long-term sustained deployment
Climate response
Stratospheric Ozone
Impact on stratospheric ozone due to changes in physical and chemical processes- Uncertainty
- Low
- Decision relevance
- Medium
- Resolvability scale
- Discernible surface climate impact
Climate response
Stratospheric Transport Feedback
Effect of stratospheric heating due to aerosol LW absorption on stratospheric transport- Uncertainty
- Low
- Decision relevance
- Low
- Resolvability scale
- Discernible surface climate impact
Climate response
Cirrus Cloud Response
Changes to cirrus clouds due to SAI, such as via changes in vertical temperature gradient- Uncertainty
- Low
- Decision relevance
- Medium
- Resolvability scale
- Large-scale testing
Climate 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 SAM- Uncertainty
- Low
- Decision relevance
- Medium
- Resolvability scale
- Long-term sustained deployment
Climate response
Surface Climate Response to Stratospheric Heating
Impacts of stratospheric heating on the surface climate via changes to stratospheric dynamics which project onto the tropospheric response- Uncertainty
- Low
- Decision relevance
- Medium
- Resolvability scale
- Long-term sustained deployment
Climate response
Tropical Circulation
Changes in tropical circulation — including monsoons, the MJO and the Walker circulation- Uncertainty
- Medium
- Decision relevance
- High
- Resolvability scale
- Long-term sustained deployment
Climate response
Extratropical Circulation
Changes in extratropical circulation – including jet streams, storm tracks and the polar vortices- Uncertainty
- Medium
- Decision relevance
- Medium
- Resolvability scale
- Long-term sustained deployment
Climate response
Atlantic Meridional Overturning Circulation
Changes to Atlantic Meridional Overturning Circulation (AMOC) strength under SAI, including tipping dynamics- Uncertainty
- Medium
- Decision relevance
- Medium
- Resolvability scale
- Long-term sustained deployment
Climate response
Stratospheric Water Vapor
Impact of increased aerosol SAD-induced stratospheric heating on eventual increased water vapor in the stratosphere- Uncertainty
- Medium
- Decision relevance
- Medium
- Resolvability scale
- Discernible surface climate impact
Earth system response
Oceanic Carbon Cycle
Impact on oceanic carbon cycle, due to changes in biogeochemistry, ocean circulation, and other drivers- Uncertainty
- Low
- Decision relevance
- Low
- Resolvability scale
- Long-term sustained deployment
Earth system response
Terrestrial Carbon Cycle
Impact on terrestrial carbon cycle of changes in NPP, carbon storage, etc.- Uncertainty
- Medium
- Decision relevance
- Low
- Resolvability scale
- Long-term sustained deployment
Earth system response
Terrestrial Vegetation
Terrestrial vegetation (including crop) response to the combined changes in CO2, temperature, water availability, direct-diffuse light ratios, etc.- Uncertainty
- Medium
- Decision relevance
- High
- Resolvability scale
- Long-term sustained deployment
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)- Uncertainty
- Medium
- Decision relevance
- Medium
- Resolvability scale
- Long-term sustained deployment
Earth system response
Surface Air Quality
Changes in PM2.5 and surface ozone and associated impact on human health- Uncertainty
- Medium
- Decision relevance
- Low
- Resolvability scale
- Discernible surface climate impact
Engineering
Ground Infrastructure
Feasibility of and timeline to develop necessary ground infrastructure to start deployment (at ~1Mt/yr)- Uncertainty
- Medium
- Decision relevance
- Medium
- Resolvability scale
- Small-scale testing
Engineering
New Aircraft Development
Feasibility of and timeline to develop and build aircraft which can deploy material at 20km- Uncertainty
- Medium
- Decision relevance
- Medium
- Resolvability scale
- Small-scale testing
Engineering
Observations for Stratospheric Processes
Feasibility and timeline to have sufficient monitoring of aerosol properties to be able to adjust deployment strategy- Uncertainty
- High
- Decision relevance
- Medium
- Resolvability scale
- Large-scale testing
Engineering
Existing Aircraft Retrofitting
Feasibility of and timeline to retrofit existing aircraft for low-altitude (15km), high-latitude (>60°N/S) (HiLLA) deployment- Uncertainty
- Low
- Decision relevance
- Medium
- Resolvability scale
- Small-scale testing
Engineering
Material Dispersion Technology
Feasibility of and timeline to research, develop, and build material dispersement technology, including but not limited to nozzles and in-flight storage- Uncertainty
- Low
- Decision relevance
- Medium
- Resolvability scale
- Small-scale testing
Engineering
Climate Response Monitoring
Feasibility of and timeline to ensure sufficient monitoring of critical climate system components whose response must be observed to maximise learning from observed changes under SAI- Uncertainty
- Medium
- Decision relevance
- Medium
- Resolvability scale
- Large-scale testing