title: Detection and attribution of vegetation greening trend in China over the last 30 years.
abstract: The reliable detection and attribution of changes in vegetation growth is a prerequisite for the development of strategies for the sustainable management of ecosystems. This is an extraordinary challenge. To our knowledge, this study is the first to comprehensively detect and attribute a greening trend in China over the last three decades. We use three different satellite-derived Leaf Area Index (LAI) datasets for detection as well as five different process-based ecosystem models for attribution. Rising atmospheric CO2 concentration and nitrogen deposition are identified as the most likely causes of the greening trend in China, explaining 85% and 41% of the average growing-season LAI trend (LAIGS) estimated by satellite datasets (average trend of 0.0070 yr(-1), ranging from 0.0035 yr(-1) to 0.0127 yr(-1)), respectively. The contribution of nitrogen deposition is more clearly seen in southern China than in the north of the country. Models disagree about the contribution of climate change alone to the trend in LAIGS at the country scale (one model shows a significant increasing trend, whereas two others show significant decreasing trends). However, the models generally agree on the negative impacts of climate change in north China and Inner Mongolia and the positive impact in the Qinghai-Xizang plateau. Provincial forest area change tends to be significantly correlated with the trend of LAIGS (P < 0.05), and marginally significantly (P = 0.07) correlated with the residual of LAIGS trend, calculated as the trend observed by satellite minus that estimated by models through considering the effects of climate change, rising CO2 concentration and nitrogen deposition, across different provinces. This result highlights the important role of China's afforestation program in explaining the spatial patterns of trend in vegetation growth.
authors.affiliation: Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China; Institute of Tibetan Plateau Research, Center for Excellence in Tibetan Earth Scicence, Chinese Academy of Sciences, Beijing, 100085, China.
authors.forename: Shilong
authors.initials: S
authors.lastname: Piao
authors.forename: Guodong
authors.initials: G
authors.lastname: Yin
authors.forename: Jianguang
authors.initials: J
authors.lastname: Tan
authors.forename: Lei
authors.initials: L
authors.lastname: Cheng
authors.forename: Mengtian
authors.initials: M
authors.lastname: Huang
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.forename: Ronggao
authors.initials: R
authors.lastname: Liu
authors.forename: Jiafu
authors.initials: J
authors.lastname: Mao
authors.forename: Ranga B
authors.initials: RB
authors.lastname: Myneni
authors.forename: Shushi
authors.initials: S
authors.lastname: Peng
authors.forename: Ben
authors.initials: B
authors.lastname: Poulter
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Shi
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Xiao
authors.forename: Ning
authors.initials: N
authors.lastname: Zeng
authors.forename: ZhenZhong
authors.initials: Z
authors.lastname: Zeng
authors.forename: Yingping
authors.initials: Y
authors.lastname: Wang
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis*; D002681:China; D057231:Climate Change; D003247:Conservation of Natural Resources; D004784:Environmental Monitoring; D065928:Forests; D008962:Models, Theoretical; D009584:Nitrogen / Q000032:analysis*; D063245:Plant Development; D058998:Remote Sensing Technology; D018531:Spacecraft; D013696:Temperature
chemical_list: D002245:Carbon Dioxide; D009584:Nitrogen
keywords: CO2 fertilization effect; China; afforestation; attribution; detection; greening trend; nitrogen deposition