Tropical wetlands: A missing link in the global carbon cycle?

Area of Science:

• Environmental Science
• Climate Science
• Ecology

Background:

• Tropical wetlands are crucial carbon sinks and sources, releasing significant methane (CH4) and carbon dioxide (CO2).
• Current Earth system models lack tropical wetland data, hindering accurate climate change predictions.
• Undisturbed tropical wetlands exhibit considerable spatial and temporal variability in greenhouse gas fluxes.

Purpose of the Study:

• To review available data on carbon balance and gas fluxes from tropical wetlands.
• To highlight the data gaps limiting global change model accuracy.
• To estimate global methane and carbon dioxide emissions from tropical wetlands.

Main Methods:

• Literature review of existing studies on tropical wetland carbon gas fluxes.
• Upscaling of in situ measurements to estimate regional and global fluxes.
• Comparison of gas fluxes between mineral and organic soils.

Main Results:

• Global emissions estimated at 90 ± 77 Tg CH4 year⁻¹ and 4540 ± 1480 Tg CO2 year⁻¹.
• Methane fluxes are higher from mineral soils; CO2 fluxes show no soil type difference.
• High CO2 and CH4 emissions correlate with high net primary productivity and litter decay.

Conclusions:

• There is an urgent need for systematic data collection on tropical wetland carbon dynamics.
• Understanding tropical wetlands is crucial for improving global climate models.
• Tropical wetlands differ significantly from northern wetlands, requiring specific research focus.