New study makes controversial weather-tweaking idea more realistic

Key Highlights:

1. Stratospheric Aerosol Injection (SAI) is a proposed geoengineering method to cool the planet by injecting aerosols into the stratosphere.
2. A new study shows SAI could be implemented at lower altitudes (13 km) using modified existing aircraft, reducing cost and deployment time.
3. Researchers simulated spraying sulphur dioxide using UKESM1 model; 12 million tonnes/year at 13 km could cool Earth by ~0.6°C.
4. Higher altitudes (20 km) require specially designed aircraft and less sulphur dioxide, but involve greater technical and financial hurdles.
5. The method is inspired by volcanic eruptions like Mount Pinatubo (1991), which had measurable cooling effects.
6. Significant risks include acid rain, ozone layer delays, regional climatic imbalances, and global geopolitical disputes.

Detailed Insights:

1. Geoengineering Strategy: SAI is one of several solar radiation modification methods aimed at reducing incoming solar energy to mitigate global warming.
2. Volcanic Analogy: Mimics natural cooling observed after volcanic eruptions, providing a natural precedent for large-scale deployment.
3. Technical Innovation: New approach targets lower altitudes (esp. polar and extratropical regions) where aircraft can reach the stratosphere without extreme modifications.
4. Cost and Accessibility: Using modified commercial aircraft like the Boeing 777F could make the technology viable within a few years, avoiding billion-dollar aircraft development.
5. Effectiveness vs. Risk Trade-off: More aerosols at lower altitude may compensate for shorter particle residence time but raise environmental and health risks.
6. Global Governance Challenge: The technology affects the entire planet; unilateral deployment may provoke international tension or unintended cross-border impacts.
7. Masking Effect: Could reduce perceived urgency of emission cuts, making countries less likely to take long-term mitigation steps.

Scientific/Technical Concepts Involved:

1. Stratospheric Aerosol Injection (SAI): Solar geoengineering method involving high-altitude injection of reflective aerosols to reduce solar radiation.
2. Tropopause: The boundary between troposphere and stratosphere; varies by latitude and determines feasible altitudes for aerosol injection.
3. UKESM1 (UK Earth System Model): Climate simulation tool used to model aerosol effects and global temperature changes.

Mains Mock Question:

Q. Discuss the prospects and challenges of Stratospheric Aerosol Injection (SAI) as a climate mitigation tool. Should India support international geoengineering research and regulation efforts?