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Increased light‐use efficiency in northern terrestrial ecosystems indicated by CO 2 and greening observations
Author(s) -
Thomas Rebecca T.,
Prentice Iain Colin,
Graven Heather,
Ciais Philippe,
Fisher Joshua B.,
Hayes Daniel J.,
Huang Maoyi,
Huntzinger Deborah N.,
Ito Akihiko,
Jain Atul,
Mao Jiafu,
Michalak Anna M.,
Peng Shushi,
Poulter Benjamin,
Ricciuto Daniel M,
Shi Xiaoying,
Schwalm Christopher,
Tian Hanqin,
Zeng Ning
Publication year - 2016
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 - 10.1002/2016gl070710
Subject(s) - greening , biosphere , environmental science , atmospheric sciences , terrestrial ecosystem , ecosystem , latitude , vegetation (pathology) , representative concentration pathways , climate change , climatology , coupled model intercomparison project , climate model , physical geography , ecology , geography , geology , biology , medicine , geodesy , pathology
Observations show an increasing amplitude in the seasonal cycle of CO 2 (ASC) north of 45°N of 56 ± 9.8% over the last 50 years and an increase in vegetation greenness of 7.5–15% in high northern latitudes since the 1980s. However, the causes of these changes remain uncertain. Historical simulations from terrestrial biosphere models in the Multiscale Synthesis and Terrestrial Model Intercomparison Project are compared to the ASC and greenness observations, using the TM3 atmospheric transport model to translate surface fluxes into CO 2 concentrations. We find that the modeled change in ASC is too small but the mean greening trend is generally captured. Modeled increases in greenness are primarily driven by warming, whereas ASC changes are primarily driven by increasing CO 2 . We suggest that increases in ecosystem‐scale light use efficiency (LUE) have contributed to the observed ASC increase but are underestimated by current models. We highlight potential mechanisms that could increase modeled LUE.