SAI: A Geoengineering Approach

Context

As global temperatures continue to rise and the world struggles to meet climate goals, scientists are exploring innovative and sometimes controversial methods to mitigate climate change. One such method gaining renewed attention is Stratospheric Aerosol Injection (SAI), a geoengineering technique that involves spraying tiny reflective particles into the upper atmosphere to reflect sunlight and cool the Earth. A recent study has made this idea more feasible, sparking debate about its potential and risks.

What is Stratospheric Aerosol Injection (SAI)?

• SAI is a process that injects aerosols, e.g., sulphur dioxide or mineral dust such as limestone and dolomite, into the stratosphere at heights of approximately 15 to 50 kilometers. These particles create a reflective layer which diminishes the amount of solar radiation received by the Earth’s surface, thus lowering global temperatures in the short term.
• This idea is based on natural processes like volcanic eruptions, which emit huge quantities of aerosols that have been known to cool the world for limited durations.

Recent Advances Making SAI More Realistic

• A newly released study in the journal Earth’s Future suggests techniques that may make SAI less expensive and simpler to implement. The study recommends different materials and methods of delivery that enhance the stratospheric lifetime and reflectivity of aerosols, and possibly lower cost and logistics.
• Moreover, the United Kingdom’s Advanced Research and Invention Agency (ARIA) has dedicated heavy funding (£56.8 million) to studying climate-cooling technologies like SAI, representing one of the first government-supported initiatives to experiment with such geoengineering techniques via controlled outdoor tests.

Potential Benefits of SAI

• Quick cooling: SAI can rapidly lower world temperatures and prevent exceeding critical climate tipping points, like the melting of the Greenland ice sheet or the disruption of oceanic circulations.
• Supporting Tool: It can be used as an interim option to provide time as the world ups its game to curtail greenhouse gas emissions and switch to clean energy.
• Cost-Effectiveness: SAI is likely to be comparatively less costly to deploy at scale compared to other climate interventions.

Controversies and Challenges

Despite its promise, SAI is highly controversial due to several reasons:

• Environmental Risks: The long-term effects on weather patterns, ozone layer depletion, and ecosystems remain uncertain. Aerosols could alter precipitation, potentially causing droughts or floods in vulnerable regions.
• Ethical and Political Concerns: There are fears that deployment could be controlled by a few powerful nations or corporations, raising issues of governance, equity, and consent from affected populations.
• Moral Hazard: Critics argue that reliance on geoengineering might reduce the urgency to cut carbon emissions, distracting from sustainable climate solutions.
• Legal and Regulatory Gaps: Currently, international agreements like the Convention on Biological Diversity impose a de facto moratorium on large-scale geoengineering, complicating research and deployment.

Global Governance and the Way Forward

Experts emphasize the need for a robust global governance framework to regulate SAI research and potential deployment. This includes:

• Transparency and Accountability: Open sharing of research data and inclusive decision-making processes involving all nations, especially those most vulnerable to climate impacts.
• Complementary Climate Strategies: SAI should not replace emission reductions but be part of a broader portfolio including renewables, carbon capture, and adaptation measures.
• Cautious Research Approach: Small-scale, controlled experiments with community consultation are essential to build trust and understand risks before any large-scale deployment.

 Source: The Hindu

UPSC Mains Practice Question

Q. Discuss various national and international approaches to combat global warming and critically examine their effectiveness. (250 words)

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