Solar Radiation Management (SRM):
- Stratospheric Aerosol Injection: This proposed technique involves injecting reflective aerosols, such as sulfur dioxide, into the stratosphere, mimicking the cooling effect of volcanic eruptions.
- Marine Cloud Brightening: Spraying seawater into the atmosphere could increase the reflectivity of marine clouds, reflecting more sunlight back into space.
- Space-Based Reflectors: Deploying large mirrors or reflective materials in space could block a portion of incoming sunlight.
Carbon Dioxide Removal (CDR):
- Direct Air Capture (DAC): As discussed in a previous section, DAC technologies capture CO2 directly from the air, which can then be sequestered underground or utilized in industrial processes.
- Bioenergy with Carbon Capture and Storage (BECCS): This technique involves growing biomass, which absorbs CO2 during growth, then burning it for energy while capturing and storing the released CO2 underground.
- Ocean Fertilization: Introducing nutrients, such as iron, to specific ocean regions can stimulate phytoplankton growth, enhancing CO2 absorption.
- Enhanced Weathering: Accelerating the natural weathering process of rocks can sequester CO2.
TRL : Varies greatly depending on the specific technology. SRM techniques are generally at a lower TRL (2-4) due to their complexity and potential global impacts. CDR techniques like DAC and BECCS are at a higher TRL (5-7), with some already being commercially implemented.