Climate warming accelerates carbon release from foliar litter-A global synthesis

Area of Science:

• Earth and Environmental Sciences
• Ecology
• Biogeochemistry

Background:

• Annual litterfall transfers over one-third of terrestrial net primary productivity to the soil.
• Litter decomposition is a critical control on atmospheric carbon dioxide (CO2) levels.
• Quantitative global projections of litter carbon release under climate change are scarce.

Purpose of the Study:

• To estimate the global response of foliar litter carbon residence time (τ) to climate change.
• To provide spatially explicit predictions of litter carbon release rates under future climate scenarios.
• To identify key drivers, including vegetation type and climate conditions, influencing litter carbon dynamics.

Main Methods:

• Compiled a global foliar litter carbon release dataset (8973 samples).
• Generated spatially explicit estimates of litter residence time (τ).
• Modeled the response of τ to projected future climate scenarios (SSPs).

Main Results:

• Global mean litter carbon release rate (k) is 0.69 year⁻¹ (range: 0.09–5.6 year⁻¹).
• Global mean τ is projected to decrease by 2.7% (SSP 1-2.6) and 5.9% (SSP 5-8.5) between 2071-2100.
• Significant regional variations observed: decreased τ in cold/arid regions, increased τ in tropical forests under SSP 5-8.5.

Conclusions:

• Vegetation type is a key factor in global litter carbon release patterns.
• Climate conditions significantly influence the response of carbon release to climate change.
• Observation-based estimates can refine carbon cycle models and improve climate feedback projections.