title: Evidence for a weakening relationship between interannual temperature variability and northern vegetation activity.
abstract: Satellite-derived Normalized Difference Vegetation Index (NDVI), a proxy of vegetation productivity, is known to be correlated with temperature in northern ecosystems. This relationship, however, may change over time following alternations in other environmental factors. Here we show that above 30°N, the strength of the relationship between the interannual variability of growing season NDVI and temperature (partial correlation coefficient RNDVI-GT) declined substantially between 1982 and 2011. This decrease in RNDVI-GT is mainly observed in temperate and arctic ecosystems, and is also partly reproduced by process-based ecosystem model results. In the temperate ecosystem, the decrease in RNDVI-GT coincides with an increase in drought. In the arctic ecosystem, it may be related to a nonlinear response of photosynthesis to temperature, increase of hot extreme days and shrub expansion over grass-dominated tundra. Our results caution the use of results from interannual time scales to constrain the decadal response of plants to ongoing warming.
authors.affiliation: 1] Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China [2] Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China [3] CAS Center for Excellence in Tibetan Plateau Earth Sciences,Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Shilong
authors.initials: S
authors.lastname: Piao
authors.affiliation: Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Nan
authors.affiliation: Centre for Ecology and Hydrology, Benson Lane, Wallingford OX10 8BB, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Huntingford
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Ciais
authors.affiliation: College of Engineering, Computing and Mathematics, University of Exeter, Exeter EX4 4QF, UK.
authors.forename: Pierre
authors.initials: P
authors.lastname: Friedlingstein
authors.affiliation: College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Sitch
authors.affiliation: 1] Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China [2] Laboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, France.
authors.forename: Shushi
authors.initials: S
authors.lastname: Peng
authors.affiliation: Department of Earth and Ecosystem Sciences, Lund University, Sölvegatan 12, SE-223 62 Lund, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Ahlström
authors.affiliation: Global Carbon Project, Commonwealth Scientific and Industrial Research Organization, Ocean and Atmospheric Flagship, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Josep G
authors.initials: JG
authors.lastname: Canadell
authors.affiliation: Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Cong
authors.affiliation: National Center for Atmospheric Research, Boulder, Colorada 80301, USA.
authors.forename: Sam
authors.initials: S
authors.lastname: Levis
authors.affiliation: Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB, UK.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Levy
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Lingli
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Lomas
authors.affiliation: Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Jiafu
authors.initials: J
authors.lastname: Mao
authors.affiliation: Department of Geography and Environment, Boston University, 675 Commonwealth Avenue, Boston, Massachusetts 02215, USA.
authors.forename: Ranga B
authors.initials: RB
authors.lastname: Myneni
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Peylin
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, France.
authors.forename: Ben
authors.initials: B
authors.lastname: Poulter
authors.affiliation: Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Shi
authors.affiliation: Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
authors.forename: Guodong
authors.initials: G
authors.lastname: Yin
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Viovy
authors.affiliation: 1] Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China [2] Laboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, France.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.affiliation: Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
authors.forename: Xuhui
authors.initials: X
authors.lastname: Wang
authors.affiliation: Max Planck Institute for Biogeochemistry, P.O. Box 10 01 64, 07701 Jena, Germany.
authors.forename: Soenke
authors.initials: S
authors.lastname: Zaehle
authors.affiliation: Department of Atmospheric and Oceanic Science, University of Maryland, College Park, Maryland 20740, USA.
authors.forename: Ning
authors.initials: N
authors.lastname: Zeng
authors.affiliation: Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
authors.forename: Zhenzhong
authors.initials: Z
authors.lastname: Zeng
authors.affiliation: Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Anping
authors.initials: A
authors.lastname: Chen
mesh_terms: D001110:Arctic Regions; D002980:Climate; D003198:Computer Simulation; D055864:Droughts; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D005843:Geography; D057232:Global Warming; D010788:Photosynthesis; D018521:Plant Physiological Phenomena; D010944:Plants; D006109:Poaceae; D063809:Satellite Imagery; D012621:Seasons; D012987:Soil; D013696:Temperature
chemical_list: D012987:Soil