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

• Published in: Nature communications Vol. 5; no. 1; p. 5018
• Main Authors: Piao, Shilong, Nan, Huijuan, Huntingford, Chris, Ciais, Philippe, Friedlingstein, Pierre, Sitch, Stephen, Peng, Shushi, Ahlström, Anders, Canadell, Josep G., Cong, Nan, Levis, Sam, Levy, Peter E., Liu, Lingli, Lomas, Mark R., Mao, Jiafu, Myneni, Ranga B., Peylin, Philippe, Poulter, Ben, Shi, Xiaoying, Yin, Guodong, Viovy, Nicolas, Wang, Tao, Wang, Xuhui, Zaehle, Soenke, Zeng, Ning, Zeng, Zhenzhong, Chen, Anping
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 16.10.2014; Nature Publishing Group
• Subjects: 704/106/47; 704/158/2165; Arctic Regions; Bioclimatology; Climate; Computer Simulation; Correlation coefficient; Drought; Droughts; Earth and Related Environmental Sciences; Ecology, environment; Ecosystem; Ecosystem models; Ecosystems; Environmental factors; Environmental Monitoring - methods; Geography; Geovetenskap och miljövetenskap; Geovetenskap och relaterad miljövetenskap; Global Warming; Growing season; Humanities and Social Sciences; Life Sciences; multidisciplinary; Natural Sciences; Naturgeografi; Naturvetenskap; Photosynthesis; Physical Geography; Plant Physiological Phenomena; Plants; Poaceae; Satellite Imagery; Science; Science (multidisciplinary); Seasons; Soil; Temperature; Tundra; Vegetation
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms6018

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. Northern Hemisphere photosynthesis is thought to respond positively to temperature variations, yet the strength of this relationship may change over time. Here, using a combination of satellite data and models, the authors assess the temporal change of this relationship over the past three decades.