Global Soil Methane Uptake Estimated by Scaling Up Local Measurements

Area of Science:

• Environmental Science
• Biogeochemistry
• Climate Science

Background:

• Aerobic soils play a vital role in atmospheric methane removal.
• Global Soil Methane Uptake (SMU) estimates are highly uncertain due to challenges in data scaling.
• Understanding SMU is critical for climate regulation and methane feedback loops.

Purpose of the Study:

• To refine global Soil Methane Uptake (SMU) estimates using a data-driven approach.
• To link global SMU budgets to local fluxes by incorporating soil properties.
• To improve projections of future SMU and identify key biomes for methane management.

Main Methods:

• Developed a data-driven model integrating 79,800 flux measurements from 198 sites.
• Varied model parameters based on soil properties to link global and local SMU.
• Analyzed SMU contributions across different biomes and projected future trends.

Main Results:

• The global SMU estimate for 2003-2018 is approximately 39.0 Tg CH4 year⁻¹, 30% higher than previous bottom-up estimates.
• Cold grasslands and deserts contribute significantly (~30%) to total SMU.
• Disturbed agricultural biomes exhibit the lowest SMU, while soil moisture is a primary driver of local SMU.

Conclusions:

• Soils have a substantial, previously underestimated, role in climate regulation via methane uptake.
• Future SMU is influenced by temperature and atmospheric methane concentrations.
• Targeting key biomes and understanding soil moisture dynamics are essential for effective methane management strategies.