Climate Change Decreased Net Ecosystem Productivity in the Arid Region of Central Asia

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.

Global Challenges and Responses: Agriculture, Economic Globalization, and Environmental Sustainability in Central Asia

“…Temperature rises in Central Asia must be addressed immediately since they have been linked to the considerable growth of the carbon source area between 2001 and 2008. A rise in temperature causes soil respiration to speed up, reducing carbon sinks in the ecosystem [20]. This is also supported by Han et al [112].…”

“…Meanwhile, Central Asia's most prominent climate changes were marked by decreasing temperature, growing glaciers, increasing precipitation, and increasing humidity during transitions from the Sub-Boreal to Sub-Atlantic period and from the Medieval Warm period to the Little Ice Age [53]. Since the twenty-first century, climate change in Central Asian countries has harmed net ecosystem productivity [20]. However, climate changes still have a positive impact, such as warmer winters and increasing precipitation in Buqtyrma River Basin areas in Kazakhstan [54].…”

“…There are several causes for these problems, including (1) crises in economic policy that do not account for the cost of services to the environment, (2) a lack of community and public sustainability education, (3) an inability to adapt to new challenges, and (4) technological constraints [58]. Hence, regional and national sustainable development policy and a better understanding of climate change is required in Central Asia [20,59]. There are various factors to keep the environment sustainable: (i) reduce environmental pollution and enable model energy; (ii) expand the use of recycling facilities and renewable energy sources; (iii) give financial support to boost renewable technologies; (iv) optimize the global trading environment with mutual compromise and participation; (v) improve the ecological laws and public education [59,60].…”

“…However, this may influence the region's escalating environmental harm. Thus, a better understanding of environmental sustainability in Central Asia is crucial for the region's long-term economic development and environmental conservation [20]. Fourth, natural resource interdependence exists among Central Asian countries.…”

Spatio-Temporal Development of Vegetation Carbon Sinks and Sources in the Arid Region of Northwest China

“…Whereas the carbon emitted through soil microbial respiration is greater than the vegetation carbon stock and behaves as the carbon source [ 4 ]. The net ecosystem productivity (NEP) represents the net carbon exchange between the atmosphere and terrestrial ecosystem, which has been widely used to quantitatively evaluate carbon sinks and sources of terrestrial ecosystems [ 5 , 6 , 7 ].…”