Context:

Reducing aerosol emissions is crucial for air quality but poses a climate paradox: aerosols cool the atmosphere by reflecting sunlight. A 2024 Geophysical Research Letters study warns that rapid aerosol cuts without reducing greenhouse gases (GHGs) could accelerate warming, especially in polluted regions like India.

Greenhouse Gases vs. Aerosols

GHGs like carbon dioxide and methane trap heat, causing long-term warming. In contrast, aerosols—sulphates, nitrates, black carbon, and dust—scatter sunlight, creating a cooling effect.

• Lifespan: GHGs persist for decades to centuries, while aerosols last days to weeks.
• Impact: GHGs cause sustained warming; aerosols provide temporary cooling but worsen air pollution.

Sudden aerosol reductions without cutting GHGs could lead to rapid temperature increases in heavily polluted areas.

India’s Industrial Dependence on Aerosols

India’s reliance on coal-based thermal power (70% of electricity) produces high aerosol emissions. These emissions have offset about 1.5°C of warming since 1906, keeping observed warming at 0.54°C instead of 2°C.

A 2020 Ministry of Earth Sciences report found India’s temperature rose 0.7°C between 1901-2018, partially mitigated by aerosols and land-use changes.

Aerosols and Monsoon Variability

Aerosols weaken monsoon circulation by altering atmospheric temperatures. The IPCC estimates aerosol cooling at 0.6°C globally, but unevenly distributed:

• Northern Hemisphere: 0.9°C cooling.
• Southern Hemisphere: 0.3°C cooling.

China’s recent aerosol cuts intensified heat waves in the Pacific and North America. Similarly, India’s aerosol reductions could disrupt monsoons, impacting agriculture and water resources.

Health vs. Climate Trade-offs

Aerosols offset warming but cause severe respiratory and cardiovascular diseases, with over 1 million pollution-related deaths annually in India. They also contribute to acid rain, smog, and weather instability.

Policy Challenges and Solutions

India must balance air pollution control with climate adaptation. The Indo-Gangetic plains, with high aerosol levels, risk severe heat stress if emissions drop without reducing GHGs.
Key policy steps:

1.   Integrate pollution control with climate adaptation.

2.   Strengthen heat action plans for vulnerable cities.

3.   Enhance climate modeling for better predictions.

4.   Phase out coal while expanding renewables.

Conclusion

Reducing aerosols is vital for public health, but without GHG mitigation, it could accelerate warming and disrupt monsoons. Sustainable policies must balance air quality improvements with climate stability.