Evidence for a weakening relationship between interannual temperature variability and northern vegetation activity

Shilong Piao (1) , Huijuan Nan (1) , Chris Huntingford (2) , Philippe Ciais (3, 4) , Pierre Friedlingstein (5) , Stephen Sitch (6) , Shushi Peng (7) , Anders Ahlström (8) , Josep Canadell (9) , Nan Cong (10) , Sam Levis (11) , Peter Levy (12) , Lingli Liu (10) , Mark Lomas (13) , Jiafu M Mao (14) , Ranga Myneni (15) , Philippe Peylin (3, 16) , Ben Poulter (17) , Xiaoying Shi (14) , Guodong Yin (1) , Nicolas Viovy (3, 16) , Tao Wang (1) , Xuhui Wang (3) , Soenke Zaehle (18) , Ning Zeng (19) , Zhenzhong Zeng (20) , Anping Chen (21)

1 Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences
2 CEH - Centre for Ecology and Hydrology [Wallingford]
3 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
4 ICOS-ATC - ICOS-ATC
5 University of Exeter
6 College of Life and Environmental Sciences [Exeter]
7 Peking University [Beijing]
8 Skane University Hospital [Lund]
9 CSIRO - Commonwealth Scientific and Industrial Research Organisation [Canberra]
10 CAS - Chinese Academy of Sciences [Beijing]
11 NCAR - National Center for Atmospheric Research [Boulder]
12 UK Centre for Ecology & Hydrology
13 University of Sheffield [Sheffield]
14 Environmental Sciences Division [Oak Ridge]
15 BU - Boston University [Boston]
16 MOSAIC - Modélisation des Surfaces et Interfaces Continentales
17 MSU - Montana State University
18 MPI-BGC - Max Planck Institute for Biogeochemistry
19 IAP - Institute of Atmospheric Physics [Beijing]
20 NERCITA - National Engineering Research Center for Information Technology in Agriculture [Beijing]
21 Princeton University

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 R NDVI-GT) declined substantially between 1982 and 2011. This decrease in R NDVI-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 R NDVI-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.

Domaines: Bioclimatologie

Shilong Piao, Huijuan Nan, Chris Huntingford, Philippe Ciais, Pierre Friedlingstein, et al.. Evidence for a weakening relationship between interannual temperature variability and northern vegetation activity. Nature Communications, 2014, 5, pp.5018. ⟨10.1038/ncomms6018⟩. ⟨hal-02927916⟩