TY - JOUR
T1 - Three Decades of Wetland Methane Surface Flux Modeling by Earth System Models-Advances, Applications, and Challenges
AU - Forbrich, Inke
AU - Yazbeck, Theresia
AU - Sulman, Benjamin
AU - Morin, Timothy H.
AU - Tang, Angela Che Ing
AU - Bohrer, Gil
N1 - Publisher Copyright:
© 2024. The Authors.
PY - 2024/3
Y1 - 2024/3
N2 - Earth System Models (ESMs) simulate the exchange of mass and energy between the land surface and the atmosphere, with a key focus on modeling natural greenhouse gas feedbacks. Methane is the second most important greenhouse gas after carbon dioxide. There are growing concerns over the rapidly increasing methane concentration in the atmosphere, underscoring the need for accurate global modeling of its emissions using ESMs. Of the multitude of sources of methane globally, wetlands are the largest natural emitters for methane, leading to significant efforts targeting their representation in ESMs with a special focus on their methane emissions. In this review, we first provide a historical overview of including wetland-methane components in ESMs and how methane modeling approaches have evolved over time. Second, we discuss recent modeling advancements that show promise for improvements in methane emissions predictions, namely the coupling of surface and atmospheric modules of ESMs, the representation of microtopography and transport mechanisms, the resolution of microbial processes at different spatial-temporal scales, and the improved mapping of wetland area extent across the different wetland types. Third, we shed light on the different challenges hindering accurate estimations of wetland-methane emissions, as shown by the consistent discrepancy between bottom-up and top-down models' predictions. Finally, we emphasize that more detailed representation of biogeochemistry and dynamic hydrology while resolving the within-wetland vegetation heterogeneity should improve model predictions, especially when coupled with expanding ground-based measurement networks and high-resolution remote sensing mapping of methane-relevant variables, such as water elevation, water table depth, and methane concentration.
AB - Earth System Models (ESMs) simulate the exchange of mass and energy between the land surface and the atmosphere, with a key focus on modeling natural greenhouse gas feedbacks. Methane is the second most important greenhouse gas after carbon dioxide. There are growing concerns over the rapidly increasing methane concentration in the atmosphere, underscoring the need for accurate global modeling of its emissions using ESMs. Of the multitude of sources of methane globally, wetlands are the largest natural emitters for methane, leading to significant efforts targeting their representation in ESMs with a special focus on their methane emissions. In this review, we first provide a historical overview of including wetland-methane components in ESMs and how methane modeling approaches have evolved over time. Second, we discuss recent modeling advancements that show promise for improvements in methane emissions predictions, namely the coupling of surface and atmospheric modules of ESMs, the representation of microtopography and transport mechanisms, the resolution of microbial processes at different spatial-temporal scales, and the improved mapping of wetland area extent across the different wetland types. Third, we shed light on the different challenges hindering accurate estimations of wetland-methane emissions, as shown by the consistent discrepancy between bottom-up and top-down models' predictions. Finally, we emphasize that more detailed representation of biogeochemistry and dynamic hydrology while resolving the within-wetland vegetation heterogeneity should improve model predictions, especially when coupled with expanding ground-based measurement networks and high-resolution remote sensing mapping of methane-relevant variables, such as water elevation, water table depth, and methane concentration.
KW - earth system models
KW - land surface models
KW - methane
KW - weltands
UR - http://www.scopus.com/inward/record.url?scp=85188475838&partnerID=8YFLogxK
U2 - 10.1029/2023JG007915
DO - 10.1029/2023JG007915
M3 - Review article
AN - SCOPUS:85188475838
SN - 2169-8953
VL - 129
JO - Journal of Geophysical Research: Biogeosciences
JF - Journal of Geophysical Research: Biogeosciences
IS - 3
M1 - e2023JG007915
ER -