Climate Change Trends and Impacts on Vegetation Greening Over the Tibetan Plateau

Abstract

The Tibetan Plateau (TP) is an ecologically fragile region that is sensitive to climate change. In the context of global climate change, the climate change trends of the TP and the vegetation dynamic response need to be investigated. Based on in situ meteorological data, Satellite Pour l'Observation de la Terre vegetation data, and Moderate Resolution Imaging Spectroradiometer land cover data, a comprehensive analysis was conducted to determine the trends of climate parameters in the TP region at different time scales (long term: 1960–2014; midterm: 1980–2014; short term 1999–2014). A consistent warming trend was observed for different temporal scales, while a warming slowdown was identified during 1999 and 2014. The warming rate was also shown to be much higher in the high‐altitude regions (>4,000 m), especially at midterm and short‐term time scales. A new cloud‐free time series of vegetation index data sets was reconstructed, and the vegetation density showed a general increasing trend along with a warming trend in the TP. The regions showing significant increases accounted for 7.63% of the total Tibetan territory. The major significant greening trend of the TP was mainly caused by climate factors. The reforestation projects may have played a minor role in the vegetation greening in specific regions of the TP. In addition, various vegetation types showed markedly different responses to climate changes. The grassland in semiarid regions, which accounted for 41.9% of the territory of the TP, was identified to be very sensitive to variations in both temperature and precipitation.

Interannual Spatiotemporal Variations of Land Surface Temperature in China From 2003 to 2018

“…Overgrazing has degraded pastures, resulting in an increase in exposed ground, which has increased the solar radiation absorbed by the ground and its LST. Regarding the Qinghai-Tibet Plateau, Zhong et al [44] pointed out that while discerning natural and anthropogenic effects on vegetation dynamics is difficult, a significant increase in barren land was observed in this region. Huang et al [45] investigated the impact of human intervention on the vegetation of the Qinghai-Tibet Plateau and reported that after 2000, the significant increase in human activities seriously affected the vitality of the vegetation in this region.…”

Local Climatic Factors Mediated Impacts of Large-Scale Climate Oscillations on the Growth of Vegetation Across the Tibetan Plateau

“…The TP has experienced significant climatic warming over the past five decades (Lu and Liu, 2010;Cai et al, 2017;Zhong et al, 2019), and the warming has accelerated since the 1980s (Lu and Liu, 2010;Zhong et al, 2019). The mean annual temperature has increased faster in the northeastern and northwestern areas than in the southeastern areas of the TP over the past five decades (Li et al, 2010;Deng et al, 2017).…”

“…Annual precipitation has increased substantially in the western, central, and northeastern areas but has decreased slightly along the southeastern and southwestern edges of the TP over the past 40 years (Zhang et al, 2017). Climatic change has resulted in substantial changes in the growth of vegetation across the TP (Piao et al, 2012;Lehnert et al, 2016;Zhu et al, 2016;Zhang et al, 2018;Zhong et al, 2019). For instance, climate warming not only advanced vegetation green-up date but also extended the length of the growing season across the TP (Liu et al, 2006;Piao et al, 2011;Dong et al, 2012) Shen et al (2016 have reported that nighttime warming advanced vegetation green-up date in most area across the TP, likely nighttime warming reduced low temperature constraints.…”

Interactive Effects of Climatic Factors on Seasonal Vegetation Dynamics in the Central Loess Plateau, China

“…Substantial research progress has been achieved in studying vegetation dynamics under climate changes in arid, semiarid and semi-humid regions by using the satellite earth observation time-series data, for example the Normalized Difference Vegetation Index (NDVI) data [5,[10][11][12]. Studies in the Tibetan Plateau region have found that vegetation cover has mainly been affected by climatic factors and increased as temperature and precipitation increased [13,14]. In central Asia, precipitation has been identified as the main factor driving vegetation growth, while temperature has been identified as a control variable for vegetation greenness [11,15,16].…”