Assessing methane emissions from tropical wetlands: Uncertainties from natural variability and drivers at the global scale
Murguia‐Flores, F; Luke, VJ; Gallego‐Sala, A
Date: 25 August 2023
Article
Journal
Global Biogeochemical Cycles
Publisher
Wiley / American Geophysical Union
Publisher DOI
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Abstract
Methane (CH4) emissions from tropical wetlands represent half of the global wetland emissions,
but uncertainties remain concerning the extent of tropical methane sources. One limitation is to
conceive tropical wetlands as a single ecosystem, especially in global land surface models. We
estimate CH4 emissions and assess their ...
Methane (CH4) emissions from tropical wetlands represent half of the global wetland emissions,
but uncertainties remain concerning the extent of tropical methane sources. One limitation is to
conceive tropical wetlands as a single ecosystem, especially in global land surface models. We
estimate CH4 emissions and assess their environmental and anthropogenic drivers. We created a
dataset with 101 studies involving 328-point measurements, classified the sites into four wetland
types, and included relevant biological and environmental information. We estimate the global
CH4 emission rate from tropical wetlands as 35 (5-160) mg CH4 m-2 d-1 (median, first and third
quartile) and an annual global rate of 94 (56, 158) Tg y-1
. Fluxes differed among the wetland
types, but except for anthropogenic factors, significant environmental drivers at the global scale
could not be quantitatively identified due to high flux variability, even within wetland types.
Coastal wetlands generate median emissions of 12(5-23) Tg y-1
. Inland deep-water wetlands emit
53 (32-114) Tg y-1
, with highly variable areal extent. Emissions from inland shallow-water
wetlands are 52(33-78) Tg y-1 with variation due to seasonal changes in water table level.
Human-made wetlands emit 17 (10-4) Tg y-1
. Pollution and N inputs from agriculture are
significant anthropogenic drivers of emissions from tropical wetlands. Specific drivers of change
need to be considered according to wetland type when estimating global emissions, as well as
their specific vulnerability to global change. Additionally, these differences should be
contemplated when implementing wetland management practices aimed at decreasing methane
emissions.
Geography
Faculty of Environment, Science and Economy
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