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Toward “optimal” integration of terrestrial biosphere models
Author(s) -
Schwalm Christopher R.,
Huntzinger Deborah N.,
Fisher Joshua B.,
Michalak Anna M.,
Bowman Kevin,
Ciais Philippe,
Cook Robert,
ElMasri Bassil,
Hayes Daniel,
Huang Maoyi,
Ito Akihiko,
Jain Atul,
King Anthony W.,
Lei Huimin,
Liu Junjie,
Lu Chaoqun,
Mao Jiafu,
Peng Shushi,
Poulter Benjamin,
Ricciuto Daniel,
Schaefer Kevin,
Shi Xiaoying,
Tao Bo,
Tian Hanqin,
Wang Weile,
Wei Yaxing,
Yang Jia,
Zeng Ning
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl064002
Subject(s) - biosphere , predictability , carbon flux , earth system science , terrestrial ecosystem , carbon cycle , environmental science , primary production , computer science , ecosystem , grid , cycling , biomass (ecology) , ecology , mathematics , statistics , biology , forestry , geometry , geography
Multimodel ensembles (MME) are commonplace in Earth system modeling. Here we perform MME integration using a 10‐member ensemble of terrestrial biosphere models (TBMs) from the Multiscale synthesis and Terrestrial Model Intercomparison Project (MsTMIP). We contrast optimal (skill based for present‐day carbon cycling) versus naïve (“one model‐one vote”) integration. MsTMIP optimal and naïve mean land sink strength estimates (−1.16 versus −1.15 Pg C per annum respectively) are statistically indistinguishable. This holds also for grid cell values and extends to gross uptake, biomass, and net ecosystem productivity. TBM skill is similarly indistinguishable. The added complexity of skill‐based integration does not materially change MME values. This suggests that carbon metabolism has predictability limits and/or that all models and references are misspecified. Resolving this issue requires addressing specific uncertainty types (initial conditions, structure, and references) and a change in model development paradigms currently dominant in the TBM community.