《全球甲烷评估》（英）-173页_13mb

Global Methane Assessment: Benefits and Costs of Mitigating Methane Emissions

Core Content

The Global Methane Assessment highlights the significant opportunities and benefits of reducing methane emissions, emphasizing that it is one of the most cost-effective strategies to slow global warming and improve public health and agricultural productivity. Methane is a potent short-lived climate pollutant (SLCP) with a global warming potential (GWP) much higher than carbon dioxide, and it contributes to the formation of ground-level ozone, which has severe health and environmental impacts. The report outlines the sources, mitigation potentials, and benefits of reducing methane emissions, and calls for urgent and coordinated global action to align with the Paris Agreement’s 1.5°C target.

Main Points

1. Methane Emissions Overview

• Methane emissions have increased faster than at any time in the last 30 years.
• Over half of global methane emissions are anthropogenic, coming from three main sectors:
  • Fossil fuels (35%): Oil, gas, and coal production and distribution.
  • Waste (20%): Landfills and wastewater treatment.
  • Agriculture (40%): Livestock emissions and rice cultivation.

2. Mitigation Potential

• By 2030, targeted measures can reduce anthropogenic methane emissions by up to 45%, or 180 million tonnes per year (Mt/yr).
• 30% of these reductions (about 120 Mt/yr) can be achieved at low or negative cost.
• Additional measures (e.g., energy efficiency, fuel switching, reduced food waste) can contribute a further 15% reduction, or 60 Mt/yr.

3. Benefits of Methane Mitigation

• Climate Benefits: Reducing methane emissions could avoid nearly 0.3°C of warming by the 2040s.
• Health Benefits: Every million tonnes of methane reduced could prevent:
  • 1,430 premature deaths annually from ozone-related health issues.
  • 4,000 asthma-related hospital visits and 90 hospitalizations.
• Agricultural Benefits: Methane mitigation could increase global crop yields by 26 million tonnes per year.
• Economic Benefits: The global monetized benefits are estimated at US$4,300 per tonne of methane reduced, with the benefits of preventing premature deaths alone amounting to US$450 billion per year.

4. Sector-Specific Mitigation Measures

• Fossil Fuel Sector:
  • Leak detection and repair.
  • Capture and utilization of vented gas.
  • Improved control of fugitive emissions.
  • Coal mine methane management.
  • Additional Measures: Renewable energy adoption, energy efficiency improvements.
• Waste Sector:
  • Improved solid waste management with recycling and energy recovery.
  • Wastewater treatment upgrades with biogas recovery.
  • Additional Measures: Reduced consumer waste, improved waste separation and recycling.
• Agricultural Sector:
  • Improved animal health and husbandry.
  • Livestock manure management.
  • Rice paddy water management and alternative practices.
  • Additional Measures: Reduced food waste, dietary changes.

Key Findings

• Low-Cost Mitigation:

  • 60% of targeted measures have low or negative mitigation costs.
  • Oil and gas and coal sectors offer the greatest potential for low-cost abatement.
  • Waste sector also presents significant cost-effective opportunities.

• Regional Variations:

  • Europe and India: Waste sector offers the largest mitigation potential.
  • China: Coal and livestock are the main sources.
  • Africa: Livestock and oil/gas.
  • Asia-Pacific (excluding China and India): Coal and waste.
  • Middle East, North America, Russia/Former Soviet Union: Oil and gas.
  • Latin America: Livestock.

• Need for Integrated Strategies:

  • Mitigation efforts must address multiple impacts on climate, air quality, public health, and agriculture.
  • A combination of targeted and additional measures is necessary to achieve the 1.5°C target.
  • Broad decarbonization strategies alone are insufficient, as they can only achieve about 30% of the required methane reductions.

• Urgency of Action:

  • Immediate implementation of targeted measures is critical.
  • The short atmospheric lifetime of methane means rapid benefits can be realized if emissions are reduced now.

Conclusion

The Global Methane Assessment underscores the importance of methane mitigation as a key strategy to achieve multiple benefits for climate, health, and agriculture. It highlights that 45% reduction in methane emissions by 2030 is both achievable and cost-effective, with significant health, economic, and environmental advantages. The report calls for greater global coordination, improved monitoring and data transparency, and policy and regulatory support to ensure that these measures are implemented effectively. The Climate and Clean Air Coalition (CCAC) plays a vital role in driving international ambition and supporting national efforts.

A web-based decision support tool is available to help users assess the benefits of methane reductions at the national level. The assessment also emphasizes the importance of behavioral and policy changes, such as reducing food waste, improving livestock management, and adoption of healthier diets, in achieving the necessary emission reductions.