Abstract
Numerous studies have confirmed that climate change leads to a decrease in the net ecosystem productivity (NEP) of terrestrial ecosystems and alters regional carbon source/sink patterns. However, the response mechanism of NEP to climate change in the arid regions of Central Asia remains unclear. Therefore, this study combined the Carnegie–Ames–Stanford approach (CASA) and empirical models to estimate the NEP in Central Asia and quantitatively evaluate the sensitivity of the NEP to climate factors. The results show that although the net primary productivity (NPP) in Central Asia exhibits an increasing trend, it is not significant. Soil heterotrophic respiration (RH) has increased significantly, while the NEP has decreased at a rate of 6.1 g C·m−2·10 a−1. Spatially, the regional distribution of the significant increase in RH is consistent with that of the significant decrease in the NEP, which is concentrated in western and southern Central Asia. Specifically, the NPP is more sensitive to precipitation than temperature, whereas RH and NEP are more sensitive to temperature than precipitation. The annual contribution rates of temperature and precipitation to the NEP are 28.79% and 23.23%, respectively. Additionally, drought has an important impact on the carbon source/sink in Central Asia. Drought intensified from 2001 to 2008, leading to a significant expansion of the carbon source area in Central Asia. Therefore, since the start of the 21st century, climate change has damaged the NEP of the Central Asian ecosystem. Varying degrees of warming under different climate scenarios will further aggravate the expansion of carbon source areas in Central Asia. An improved understanding of climate change impacts in Central Asia is critically required for sustainable development of the regional economy and protection of its natural environment. Our results provide a scientific reference for the construction of the Silk Road Economic Belt and global emissions reduction.
Highlights
Since 1880, the average global temperature has increased by 0.85 ± 0.2 ◦ C [1]
Studies have found that farmland, grassland, forest, and shrub share a similar response to climate change; grassland is the most sensitive ecosystem in Central Asia [23]
The simulation was determined by two variables, i.e., the absorbed photosynthetically active radiation (APAR) (MJ/m2 ) and light energy conversion (ε) (g C/MJ), as follows: net primary productivity (NPP) = APAR × ε
Summary
Since 1880, the average global temperature has increased by 0.85 ± 0.2 ◦ C [1]. The burning of fossil fuels and the rapid reduction in the forest area have resulted in the emission of large quantities of carbon into the atmosphere. In the context of climate change, research on the ecosystem carbon cycle in arid areas of Central Asia has significantly increased [22]. Studies have found that farmland, grassland, forest, and shrub share a similar response to climate change; grassland is the most sensitive ecosystem in Central Asia [23] Both climate change and grazing affect the grassland ecosystem, which is the main carbon source [24]. Determining the contribution of precipitation and temperature changes to the NEP of terrestrial ecosystems in Central Asia is necessary, as well as the link between carbon source/sink areas and increased drought. In this study, Central Asia was selected as the research area, and the empirical models of forest and grassland ecosystems were combined to estimate the NEP of the Central Asian terrestrial ecosystem.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
