Mitigating methane emissions from municipal solid waste in Chinese cities

Area of Science:

• Environmental Science
• Climate Change Research
• Urban Sustainability

Background:

• Rapid urbanization in China presents substantial methane (CH4) emission challenges from municipal solid waste (MSW).
• These emissions pose a significant obstacle to achieving China's net-zero methane target.
• Effective waste management strategies are crucial for mitigating climate impact.

Purpose of the Study:

• To establish the first city-level inventory of MSW-CH4 emissions in China (2006-2023).
• To identify primary drivers influencing changes in MSW-CH4 emissions.
• To inform tailored policies for achieving China's net-zero MSW-CH4 goals.

Main Methods:

• Development of a comprehensive city-level inventory for municipal solid waste methane emissions.
• Analysis of emission data from 2006 to 2023 to identify trends and drivers.
• Scenario modeling to project future emission pathways under different waste management strategies.

Main Results:

• A significant 84.7% reduction in MSW-CH4 emissions across Chinese cities since 2017.
• Megacities and large cities contributed 80% of the total emission reductions.
• Transition from landfilling to incineration and methane recovery are key drivers, particularly in larger urban areas.

Conclusions:

• Tailored waste management policies are essential for different city sizes to meet net-zero methane goals.
• A no-landfill, anaerobic digestion-focused strategy could enable negative/near-zero emissions in megacities and large cities by 2060.
• Small and microcities require enhanced incineration capacity to achieve emission reduction targets.