2010年-世界发展银行全球_Sustainable_Land_Management_for_Mitigation_of_and_Adaptation_to_Climate_Change_187页_7mb

Summary of Sustainable Land Management for Mitigation of and Adaptation to Climate Change

Core Content

This report, authored by Rattan Lal and Enos E. Esikuri, explores the role of Sustainable Land Management (SLM) in addressing climate change (CC) through both mitigation and adaptation strategies. It emphasizes the importance of SLM in developing countries, particularly in the tropics and subtropics, where land degradation and food insecurity are prevalent. The report outlines various SLM technologies and practices that can restore degraded soils, enhance carbon sequestration, and improve agricultural productivity, while also considering the co-benefits such as increased biodiversity and water quality.

Main Objectives

• To demonstrate the benefits of sustained investment in SLM for climate change adaptation and mitigation.
• To highlight the potential of SLM in enhancing food security and natural resource management.
• To provide a comprehensive overview of SLM technologies and their application in different ecosystems and land uses.
• To identify constraints and strategies for promoting SLM in developing countries.

Key Points and Main Views

1. Climate Change and Greenhouse Gas Emissions

• Anthropogenic activities, such as land use conversion and fossil fuel combustion, are the primary causes of increased atmospheric CO₂ and other greenhouse gases (GHGs).
• The global warming potential (GWP) of GHGs varies: CO₂ = 1, CH₄ = 21, N₂O = 310.
• Land use conversion has led to significant loss of soil organic carbon (SOC), with some soils losing up to 75% of their original carbon pool.

2. Role of SLM in Climate Change Mitigation and Adaptation

• SLM technologies can create positive C, water, and elemental balances, enhance net primary productivity, and improve agronomic yield.
• SLM is essential for adapting to climate change, especially in developing countries where land degradation is severe.
• SLM practices can mitigate climate change by increasing carbon sequestration and reducing net emissions.

3. Ecosystems and SLM Potential

• Tropical Forest Ecosystems (TFEs):

  • Natural regrowth and forest succession have a technical potential for C sequestration of 0.8-1.0 Gt C/yr.
  • Forest plantations can contribute 0.2-0.5 Gt C/yr but may have trade-offs such as water balance disruption and biodiversity loss.

• Tropical Savanna and Rangelands Ecosystems (TSREs):

  • Management of these ecosystems has a C sequestration potential of 0.3-0.5 Gt C/yr.
  • Overgrazing must be avoided to prevent degradation and loss of soil C.

• Cropland Management:

  • World cropland soils (~1500 million hectares) have a large C sink capacity, with potential for 0.6-1.2 Gt C/yr.
  • Practices such as no-till (NT) farming, integrated nutrient management (INM), and water conservation enhance productivity and reduce emissions.

• Desertification and Salt-Affected Soils:

  • Restoration of degraded and desertified soils can sequester 0.4-1.0 Gt C/yr.
  • Salt-affected soils can also contribute to C sequestration, with potential of 0.4-1.0 Gt C/yr.
  • Techniques like biochar, manuring, and agroforestry can improve soil quality and reduce salinity.

4. Co-Benefits of SLM

• SLM contributes to improved soil quality, increased input use efficiency, enhanced water resources, and increased biodiversity.
• It helps alleviate food insecurity, which affects ~1 billion people globally.
• SLM can increase agronomic yields by 300-400 kg/ha for maize, 40-60 kg/ha for soybeans, and so on, leading to increased food production and farm income.

5. Strategies for Promoting SLM

• Payments for Ecosystem Services (PES) and carbon and green water credits can incentivize SLM adoption.
• SLM must be integrated into broader development strategies to address both poverty and climate change.
• Site-specific SLM technologies are essential, and the choice of technology depends on local conditions.

6. Constraints to SLM Adoption

• Limited institutional capacity and resources in developing countries.
• Trade-offs between SLM practices and other land uses (e.g., agriculture, forestry).
• Policies must support SLM to ensure its success and sustainability.

Conclusion

• The global potential for C sequestration through SLM is estimated at 2.8-5.3 Gt C/yr, with economic potential at 50-75% of that.
• SLM can offset fossil fuel emissions at a rate of 2-3 Gt C/yr and reduce atmospheric CO₂ by 120-150 ppm over the 21st century.
• SLM is a win-win strategy for climate change mitigation, adaptation, food security, and poverty reduction in developing countries.

Key Information

• SLM Technologies: No-till farming, integrated nutrient management, agroforestry, biochar, water harvesting, and improved pasture management.
• SLM Benefits: Enhanced soil productivity, reduced GHG emissions, improved water quality, increased biodiversity, and increased farm income.
• SLM Challenges: Institutional limitations, policy misalignment, and trade-offs between different land uses.
• SLM Opportunities: Payments for Ecosystem Services (PES), carbon markets, and integration with broader development programs.

Areas of Focus

• Tropical and Sub-tropical Regions: Emphasis on TFEs, TSREs, croplands, and degraded soils.
• Developing Countries: Especially those in Sub-Saharan Africa, South Asia, and the Caribbean.
• Global Perspective: SLM has potential across all biomes and is crucial for addressing climate change on a global scale.

Future Outlook

• SLM must be scaled up to achieve significant climate change mitigation and adaptation outcomes.
• There is a need for more awareness and investment in SLM to realize its full potential in combating climate change and improving food security.