Evapotranspiration is a sensitive parameter for assessing climate change. It controls energy and mass exchange and is a descriptor of drought in arid‐ and semi‐arid regions. Using the Mann–Kendall (M–K) test, Sen's slope estimator, and the stepwise regression, temporal, and spatial variations in potential evapotranspiration (ET₀) and its dominant factors were analysed. The analysis was based on data from 173 meteorological stations in a desertification‐prone region of China over the period from 1960 to 2013. The annual ET₀ decreased prior to 1990s and increased thereafter. The majority of stations had a decreasing ET₀ trend, especially in summer, in which the average slope of all stations was −2.43 mm decade⁻¹. Analysis of determining factors showed that a decrease in wind speed was the primary factor associated with decreasing ET₀. The trend magnitude of ET₀ increased from −2.25 mm decade⁻¹ to −7.43 mm decade⁻¹ as wind speed increased, then decreased to −3.00 mm decade⁻¹. Decreasing ET₀ and increasing P in the western region led to decrease in the aridity index, suggesting a wetter climate and reduced desertification. Increasing aridity index in the eastern region reduced the vegetation cover and facilitated desertification processes, which might be a disadvantage for ecological reconstruction and desertification control. Better understanding of the response of ET₀ to regional climate change may facilitate efficient use of limited water resources and establish management strategies that can combat desertification and maintain ecological security in a desertification‐prone region.

The abandonment and cultivation of croplands in the Eurasian Steppe has become the focus of global and regional food security and agricultural policy-making. A large area of cropland in some post-Soviet countries has proven to be abandoned with the disintegration of the Soviet Union; however, it is unclear as to whether Kazakhstan also experienced a similar change as one of the main food providers for the former Soviet Union. In this study, we used the annual land cover dataset (1992–2015) from the European Space Agency, Climate Change Initiative (ESA-CCI) to detect spatio-temporal characteristics of rainfed and irrigated cropland changes in Kazakhstan. The Mann–Kendall test and regime shift analysis showed that rainfed and irrigated cropland at national level had a significant increasing trend with a significant rising up to 1999 and stagnation during 2000–2015, which was further confirmed with analysis at 14 regions. The greatest contributor to rainfed and irrigated croplands was steppes, followed by shrinkage of water bodies since 2005 to a great extent, rapid urbanization process resulted in losses of a part of irrigated oases. The trend surface analysis indicated that reorganized stable pattern characterized by rainfed cropland in north and irrigated cropland in south was driven by the strategy of the gradual agricultural development of oases. The nonexistence of cycle between the abandonment and recultivation proved that newly-gained cropland from steppe may be less degraded and more productive for sustainable land use in Kazakhstan. In conclusion, this study can provide strong evidence for sustainable land use and a basis for food security policy-making in Kazakhstan, and even all of the Central Asian countries in the future.

The response of potential evapotranspiration (ET0) to widespread irrigation is important to fully understand future regional climate changes and to infer adaptive management of agricultural water resources. The quantitative impact of irrigation on ET0 from 1960 to 2013 was evaluated using historical time series data of daily meteorological observations in the hyper-arid region of northwest China. The decreasing trends in ET0 were accelerated for meteorological stations in regions with oasis agriculture, especially in the summer and during the growing season. Irrigation led to a cooling effect on temperature, increased relative humidity and precipitation. All of these changes contributed to a larger decrease of ET0 trend. The findings of this study advance our insight into the effects of irrigation on dynamics in ET0 and meteorological factors. Further investigations to understand how ET0 responds to climate change and agricultural irrigation could provide guidance for determining effective measures of water resources for adapting to global change.

In order to examine temperature changes and extremes in the Beijing-Tianjin Sand Source Region (BTSSR), ten extreme temperature indices were selected, categorized, and calculated spanning the period 1960–2014, and the spatiotemporal variability and trends of temperature and extremes on multitimescales in the BTSSR were investigated using the Mann-Kendall (M-K) test, Sen’s slope estimator, and linear regression. Results show that mean temperatures have increased and extreme temperature events have become more frequent. Annual temperature has recorded a significant increasing trend over the BTSSR, in which 51 stations exhibited significant increasing trends (p<0.05); winter temperature recorded the most significant increasing trend in the northwest subregion. All extreme temperature indices showed warming trends at most stations; a higher warming slope in extreme temperature mainly occurred along the northeast border and northwest border and in the central-southern mountain area. As extreme low temperature events decrease, vegetation damage due to freezing temperatures will reduce and low cold-tolerant plants may expand their distribution range northward to revegetate barren areas in the BTSSR. However, in water-limited areas of the BTSSR, increasing temperatures in the growing season may exacerbate stress associated with plants relying on precipitation due to higher temperatures combining with decreasing precipitation.