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Simple Summary: This work aims to analyze flocks' management practices and sheep breeders' perceptions of the impact of climate change to enhance the resilience of the sheep production systems in the Tunisian semi-arid region. The results revealed three main sheep production systems: the agro-pastoral rain-fed system (AGPRF), the agro-pastoral irrigated system (AGPI), and the agro-sylvo-pastoral system (AGSP). Each production system is characterized by specific management and productive parameters that are used by farmers to build resilience actions. However, farmers' climate change perceptions are mostly the same across the three sheep production systems: a decrease in precipitation and an increase in temperatures and extreme events, which negatively influence feedstuff availability and costs. Global climate change inflicts unambiguous risks on agricultural systems and food security. Small ruminants are known for their ability to adapt to changing environmental conditions. This paper aims to characterize sheep production systems in a vulnerable agricultural zone and the breeders' perceptions of climate change to apprehend challenges that they are confronting, and formulate resilience actions. The data analysis is based on 94 semi-structured surveys of sheep farmers carried out in the Tunisian semi-arid region. The PCA analysis results revealed three main sheep production systems. The agro-pastoral rain-fed system (AGPRF) is dominant (55%), with large farms and common pastures integrating cereals and fodder. The agro-pastoral irrigated system (AGPI: 20%) is characterized by small-area and forage irrigation (1.8 ha) and a smaller number of ewes but a greater use of animal feed supplementation. The agro-sylvo-pastoral system (AGSP: 25%) is a system where grazing is based on common lands and using tree sub-products, while the agricultural area is exclusively used to cultivate cereal crops. Sheep breeders' climate perceptions are summarized as unpredictable climate events, a decrease in precipitation, and an increase in temperature. Resilience actions principally consist of reducing flocks' numbers, using alternative local feed, fodder, and water resources, and building more shelters and planting more trees in the grazing areas. Nevertheless, cost-effectiveness should be considered in such vulnerable zones to insure the sheep production systems' sustainability. [ABSTRACT FROM AUTHOR]

The Tarim Basin is a large inland arid basin in the arid region of northwest China and has been experiencing significant "warming and wetting" since 1987. As a result, the purpose of this paper is to determine whether the climate transition phenomenon occurred in the Tarim Basin as well as the role of atmospheric circulation in this process. We use meteorological data and atmospheric circulation indexes to study the seasonal trends of climate change in this region from 1987 to 2020 to understand how they are affected by atmospheric circulation. The findings show that, from 1987 to 2020, the Tarim Basin experienced significant warming and wetting; with the exception of the winter scale, all other seasonal scales exhibited a clear warming and wetting trend. From the perspective of spatial distribution, most of the areas showed a significant warming trend, and the warming amplitude around the basin is greater than that in the central area of the basin. However, there are significant regional differences in precipitation change rates. Meanwhile, wavelet analysis shows that there is a significant oscillation period of 17–20 years between climate change and the atmospheric circulation index during 1987–2020. The correlation analysis shows that the Pacific decadal oscillation (PDO) and El Niño-Southern Oscillation (ENSO) are the main influencing factors of climate change in the Tarim Basin at different seasonal scales, while the teleconnection of the Arctic Oscillation (AO) and North Atlantic Oscillation (NAO) is low and the PDO dominates the summer and autumn temperature changes in the Tarim Basin. The research results of this paper show that, despite the warming and wetting trends since 1987 in the Tarim Basin, the climate type did not change. From 1987 to 2020, the main teleconnection factors of climate change in the Tarim Basin were PDO and ENSO. [ABSTRACT FROM AUTHOR]

Global climate change affects biodiversity patterns, especially in arid and semi-arid regions such as the Mongolian plateau, one of the most ecologically fragile regions in the world. Three dynamic habitat indices (DHIs) were related to the productivity hypothesis and calculated based on FAPAR, including cumulative productivity ( D H I c u m indicates the availability of resources such as food supply and habitat in a year, representing available energy), minimum productivity ( D H I m i n indicates the limitations of food and habitat resources in a year, representing environmental stress), and seasonal productivity ( D H I s e a denotes the change in productivity in a year, representing environmental stability). In this paper, we investigated the distribution pattern of species richness on the Mongolian Plateau based on the productivity hypothesis. We constructed models of the richness of three species (mammals, birds, and amphibians) using DHIs and climate variables to explain patterns of species richness on the Mongolian Plateau. The results revealed that, on the Mongolian plateau, there is a relatively high correlation between DHIs and species richness, especially with D H I c u m (R = 0.59 for mammals, R = 0.73 for birds, and R = 0.58 for amphibians). There was a significant non-linear relationship between DHIs and species richness, as the model predictive power was significantly enhanced with GAM and RF. The inclusion of climate variables significantly improved the explanatory power of various models for the mammal, bird, and amphibian species richness on the Mongolian Plateau, with the best results for RF (0.89, 0.94, and 0.91, respectively). The influence of climate variables on species richness patterns in the importance ranking was higher than that of DHIs. Climate also has an influence on species richness. Vegetation productivity and climatic factors are good determinants of species richness on the Mongolian Plateau and should be carefully considered in future studies. [ABSTRACT FROM AUTHOR]

In the context of global warming, snow cover changes have an extremely important impact on the hydrological cycle and the redistribution of water resources in arid and semi-arid regions. In this paper, based on the daily cloud-free snow area remote sensing product data in the source region of Yangtze River (SRYR) from 2000 to 2019, the snow phenology variables such as the snow cover day (SCD), snow onset date (SOD), snow end date (SED), and snow duration day (SDD) were extracted separately for each hydrological year, and the vertical distribution of snow cover area (SCA) in the SRYR was analyzed by combining with the digital elevation model (DEM). In addition, we also combined climate factors and land cover types to further explore the spatiotemporal variation characteristics of snow phenology in response to different influencing factors, in order to reveal the spatiotemporal variation patterns of snow cover in the SRYR. The results showed that: (1) The SCA in the SRYR has a more obvious vertical distribution, with the maximum SCA reaching 61.58% at high elevation, while at low elevation, the SCA is mostly below 20%. The distribution of SCD in the study area showed a significant exponential correlation with DEM (R2 = 0.87). (2) The area of SOD in the SRYR showed an advanced trend of about 63.37%, while the area of SED showed a delayed trend of about 69.59%, and the area which showed significant trends is 4.29% and 4.36%, respectively. Therefore, the trends of both SOD and SED showed insignificant changes. (3) Temperature change is the main factor affecting the change of snow cover in the SRYR. Among them, 90.9% of the regions showed a significant positive correlation between temperature and SCD, while precipitation showed a significant negative correlation with SCD in about 75.3% of the total area of SRYR. Under the stable snow area (SCD > 60), the land cover type is glacial or permanent snow about 1.5 × 103 km2, which covers almost the entire glacial or permanent snow of the SRYR. [ABSTRACT FROM AUTHOR]

Compound droughts and heatwaves (CDHWs) are likely to cause more severe natural disasters than a single extreme event, and they have been exacerbated by rapid global warming. Based on high-resolution grid data, this study combines the daily-scale ERA5-Land dataset and the monthly-scale SPEI dataset with multiple indicators to analyze CDHWs. We calculated and analyzed the temporal and spatial modal distribution of CDHWs in Central Asia from 1981 to 2018, and in this paper, we discuss the sequence relationship between drought events, heatwave events, and CDHWs. The results show that the number of CDHWs in the study region have increased over time and expanded in terms of area, especially in eastern and southwestern Central Asia. The tsum (total frequency of CDHWs) was 0.5 times higher than the total heatwave frequency and it increased at a rate of 0.17/yr. The maximum duration of tmax (maximum duration of CDHWs in days) was 17 days. Furthermore, the occurrence rate of tmax was 96.67%, and the AH (CDHWs' accumulated heat) had a rate of 97.78%, which, upon examination of the spatial trend pattern, accounted for the largest increase in terms of area. We also found that the TAH (CDHWs' average temperature anomalies, SPEI < −0.5) shows obvious seasonality, with the increases in winter and spring being significantly greater than the increases in summer and autumn. The intensity of the CDHWs was stronger than that of a single extreme event, the temperature anomaly was higher than the average of 0.4–0.8 °C, and there was a north–south spatial pattern across the study region. In eastern and northwestern Central Asia, the AH and heatwaves (SPEI < −0.5) increased by 15–30 times per year on average. During the transition from the base period to the reference period, CDHWs increased by 25%, and the number of dry days prior to the CDHWs decreased by 7.35 days. The conclusion of our study can provide a theoretical basis for coping with climate change in arid zones. [ABSTRACT FROM AUTHOR]

In recent years, the warming–wetting trend in the arid region of Northwest China has attracted widespread attention. To reveal whether this phenomenon exists in the whole Pan-Central-Asia arid region, this paper adopts the latest monthly gridded dataset of the Climate Research Unit Time Series version 4.05 (CRU TS v4.05) and the multi-model ensemble data of the Coupled Model Intercomparison Project Phase 6 (CIMP6) for discussion from multiple perspectives. The results show that the Pan-Central-Asia arid region has been getting warmer and wetter in the last 80 years. Since the turn of the 21st century, there has been an apparent slowdown in the regional wetting trend despite the acceleration of precipitation increase, mainly caused by the growth in evapotranspiration potential. The interannual scale dominates the precipitation change, including significant quasi-three-year and quasi-six-year cycles. The interannual variability in precipitation is mainly affected by the change in the phases of Pacific decadal oscillation (PDO), while long-term variation dominates the temperature change, which is significantly related to the variations in the Arctic oscillation (AO). Thus, future research and predictions of regional precipitation should focus on the PDO variations, followed by the Southern Oscillation Index (SOI), whereas for research on, and predictions of, temperature, the effect of AO variations should be emphasized. Except for a few regions in Central-Eastern Mongolia and Central Kazakhstan, precipitation levels in most parts of the Pan-Central-Asia region have been increasing. The regional temperature exhibits a distribution pattern which decreases from northwest to southeast. The increase in precipitation in the Pan-Central-Asia arid region alleviates the drought in most regions, including most of Northwest China. However, the arid and semi-arid climate patterns in this region have not changed. The warming–wetting trend will significantly accelerate in medium-emissions scenarios in the next 80 years. Although the increase in precipitation may be a positive aspect of this trend, the rise in potential evapotranspiration caused by sharp warming may cause greater challenges to the regional climate and ecological environment. [ABSTRACT FROM AUTHOR]

The effects of global climate change and human activities are anticipated to significantly impact ecosystem services (ESs), particularly in urban agglomerations of arid regions. This paper proposes a framework integrating the dynamic Bayesian network (DBN), system dynamics (SD) model, patch generation land use simulation (PLUS) model, and the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model for predicting land use change and optimizing ESs spatial patterns that is built upon the SSP-RCP scenarios from CMIP6. This framework is applied to the oasis urban agglomeration on the northern slope of the Tianshan Mountains in Xinjiang (UANSTM), China. The findings indicate that both the SD model and PLUS model can accurately forecast the distribution of future land use. The SD model shows a relative error of less than 2.32%, while the PLUS model demonstrates a Kappa coefficient of 0.89. The land use pattern displays obvious spatial heterogeneity under different climate scenarios. The expansion of cultivated land and construction land is the main form of land use change in UANSTM in the future. The DBN model proficiently simulates the interactive relationships between ESs and diverse factors. The classification error rates for net primary productivity (NPP), habitat quality (HQ), water yield (WY), and soil retention (SR) are 20.04%, 3.47%, 4.45%, and 13.42%, respectively. The prediction and diagnosis of DBN determine the optimal ESs development scenario and the optimal ESs region in the study area. It is found that the majority of ESs in UANSTM are predominantly influenced by natural factors with the exception of HQ. The socio-economic development plays a minor role in such urban agglomerations. This study offers significant insights that can contribute to the fields of ecological protection and land use planning in arid urban agglomerations worldwide. • An integrated framework combining DBN, SD, PLUS and InVEST models was proposed. • Impact of natural and socioeconomic factors on ESs was determined under climate scenarios. • The spatial pattern of ESs was optimized and partitioned using DBNs. • ESs in arid oasis urban agglomerations are mainly affected by natural factors. [ABSTRACT FROM AUTHOR]

Variability in soil moisture has implications for regional terrestrial environments under a warming climate. This paper focuses on the spatiotemporal variability in the intra-annual persistence of soil moisture in China using the fifthgeneration reanalysis dataset by the European Centre for Medium-Range Weather Forecasts for the period 1979-2018. The results show that in China, the mean intra-annual persistence in the humid to arid zones increased from 60 to 115 days in the lower layer but decreased from 19 to 13 days and from 25 to 14 days in the upper and root layers, respectively. However, these changes were strongly attenuated in extremely dry and wet regions due to the scarcity of soil moisture anomalies. Large changes in persistence occurred in the lower soil layer in dryland areas, with a mean difference of up to 40 days between the 2010s and the 1980s. Overall increasing trends dominated the large-scale spatial features, despite regional decreases in the eastern arid zone and the North and Northeast China plains. In the root layer, the two plains experienced an expanded decrease while on the Tibetan Plateau it was dominated by decadal variability. These contrasting changes between the lower and root layers along the periphery of the transition zone was a reflection of the enhanced soil hydrological cycle in the root layer. The enhanced persistence in drylands lower layer is an indication of the intensified impacts of soil moisture anomalies (e.g., droughts) on terrestrial water cycle. These findings may help the understanding of climate change impacts on terrestrial environments. [ABSTRACT FROM AUTHOR]

The literature on barriers to climate change adaptation has largely focused on non-climatic barriers and has provided less insight into climate-induced barriers. Responding to this lacuna, this paper examines the connections between climate change and agricultural adaptation strategies of smallholder farmers in northern Ghana. Results from the qualitative fieldwork show that climatic changes have been accompanied by increases in climate change extremes (CCEs) over the last three decades. In order to adapt, smallholder farmers use improved crop varieties and other support strategies. Paradoxically, however, CCEs have undermined these strategies in several instances, causing crop yields to fall short of their actual potential and leading to financial indebtedness. Therefore, the results showcase that overcoming non-climatic barriers to the uptake of agricultural adaptation strategies is a necessary but insufficient condition for achieving successful adaptation outcomes. This is the case since new barriers to the adaptation process are constantly emerging, and CCEs are an example of this. [ABSTRACT FROM AUTHOR]

This paper reviews the existing research on Sideroxylon mascatense, and provides an argument for being considered a fruit crop in cultivated production systems in the Sultanate of Oman and elsewhere. Climate change due to global warming has adverse effects on the agro-ecosystems of mountain regions in marginal climate zones. For example, in the Western Hajar Mountains of Oman, yields of the temperate fruit crops have decreased in recent years as temperature and other climate anomalies have increased. Other fruit-bearing wild plants have also been impacted by extreme weather fluctuations, particularly those that occupy a narrow altitudinal range. One such plant is S. mascatense, a currently underutilized fruiting plant found growing in the wild all through the Middle East and other arid mountainous regions. Two fruiting types of S. mascatense are found in Oman, both of which are seasonally wild harvested by mountain inhabitants and sold in markets as well as along the roadsides. While some specimens exist in cultivated areas, propagation and new plantings are non-existent. Regeneration in the wild is also in decline in Oman, possibly due to climate change. Increasing S. mascatense populations could be achieved via propagation, as well as commercial cultivation, although further research is needed into cropping systems and best practice methods. [ABSTRACT FROM AUTHOR]

The systematic bias of the estimated average temperature using daily Tmax and Tmin records relative to the standard average temperature of four time-equidistant observations and its effect on the estimated trend of long-term temperature change have not been well understood. This paper attempts to evaluate the systematic bias across mainland China using the daily data of national observational stations. The results revealed that the positive bias of annual mean temperature was large, reaching 0.58°C nationally on average; regional average bias was lowest in the northwest arid region and highest in the Qinghai–Tibetan Plateau; the bias was low in spring and summer and high in autumn and winter, reaching its lowest point in mid- and late May and highest point in early November. Furthermore, the bias showed a significant upward trend in the past 50 years, with a rising rate of 0.021°C (10 yr)−1, accounting for about 12% of the overall warming as estimated from the data of the observational network; the largest positive trend bias was found in the northwest arid region, while the east monsoon region experienced the smallest change; the most remarkable increase of the bias occurred after early 1990s. These results indicate that the customarily applied method to calculate daily and monthly mean temperature using Tmax and Tmin significantly overestimates the climatological mean and the long-term trend of surface air temperature in mainland China. [ABSTRACT FROM AUTHOR]

• Based on the principles of SPEI, we develop a GDAI. • The relationship between GDAI and AI is closer. • The correlation between GDAI and SPEI is also better. Climate change has increased the risk of drought in both arid and non-arid regions of the globe. Therefore, in order to monitor and evaluate global drought and aridity, based on the principle of standardized precipitation evapotranspiration index (SPEI), this paper selected precipitation and potential evapotranspiration data and used a frequency calculation method to develop a multi-scale global drought aridity index (GDAI) that concurrently considers spatial and temporal variation characteristics: the spatiotemporal standardized precipitation evapotranspiration index. The index was compared with the aridity index (AI) and SPEI. The results showed that the correlation coefficients between GDAI and AI were greater than 0.8 in most areas, and the relationship was closer and could reveal the global aridity and wetness zoning. In addition, the correlation between GDAI and SPEI was also better, which could capture the temporal change characteristics of drought. Moreover, this study also compared the grades of GDAI and SPEI with the actual drought grades in Yunnan from September 2009 to August 2010, and found that GDAI was better than SPEI, and GDAI was the most accurately evaluated at the 3 month time scale, with an accuracy rate of 86.11%. Therefore, this index is more helpful for the assessment and monitoring of global drought and aridity. [ABSTRACT FROM AUTHOR]

Water resources in dry environments are becoming scarcer, especially under the changing climate. In response, rainwater harvesting (RWH) is being reemphasized with calls to revive the practice. Ancient knowledge on RWH - mainly the collection through runoff, storage, and use of rainwater for various purposes - is still relevant, especially for dry environments. However, many old practices and technologies may not be suitable or feasible for the present and future. Little has been done to modernize and (or) develop new practices and technologies based on ancient indigenous knowledge. Modernizing old practices or developing new ones and using them in integrated rangelands restoration packages with enabling policy environment can unlock their potential in many water-scarce regions of the world. This paper reviews the state-of-the-art of micro-catchment rainwater harvesting (MIRWH) in dry environments and discusses the opportunities available and the major obstacles faced in using it to restore degraded agro-pastoral ecosystems and support their sustainability. The review highlights the knowledge behind it, the practices developed over the years, and their relevance to today and the future. The paper indicates areas of modernization that can make it more feasible for the future of the dry environments, especially their role in mitigating and adapting to climate change. Conventional and passive approaches to restoring/rehabilitating degraded dry agro-pastoral ecosystems are either too slow to show an obvious impact or not progressing satisfactorily. One main reason is that, because of land degradation, the majority of rain falling on such ecosystems and needed for revegetation is lost with little benefit being gained. Adopting a more progressive intervention to alter the processes of degradation and move towards new system equilibrium is required. MIRWH can enable a large portion of this otherwise lost rainwater to be stored in the soil, and, if used in an integrated packages including suitable plant species and sound grazing management, it may support meaningful vegetation growth and help system restoration. The Badia Benchmark project, implemented by ICARDA in Jordan and Syria, has demonstrated the potential for adoption at large scale in similar environments. This case study illustrates the potential and the constraints of this practice. [ABSTRACT FROM AUTHOR]

Periodic vegetation patterns (PVPs) are striking features of many global drylands. Although they have attracted wide research study, resulting in many hypotheses, their origin and controlling factors remain unresolved. Theoretical works dominate a large literature seeking to account for the occurrence and properties of PVPs, especially banded vegetation patterns ('tiger bush'). In light of the plethora of theoretical studies, there is a need for more empirical observation and monitoring of PVPs, especially their responses to climatic variability and to foreshadowed climatic change. This paper highlights key results derived from more than 20 years of field study and monitoring of banded vegetation in arid New South Wales, Australia, where severe drought is a recurring feature. It advances the view that in this study area, and hence perhaps in other regions, local factors including plant physiology, soil properties, and climatic characteristics result in PVPs whose development and functioning might be quite unlike those of other regions. Importantly, these local characteristics appear to confer on the regional PVPs a considerable resilience to drought, and hence perhps to climate change. The field evidence from the study area suggests that, despite predictions of a number of theoretical analyses, the PVPs are not facing imminent collapse. Generalised and non-specific models of PVPs require more realistic parameterisation and more thorough validation than has been customary, and this will require additional field evidence of the kind reviewed here. Highlights: • highlights results of field study of banded vegetation in the Broken Hill region of Australia over more than 20 years • patterned vegetation in this area appears to be resilient in the face of drought and grazing pressure • contrary to most model predictions, the vegetation bands do not migrate upslope, and do not undergo pattern change during severe drought • direct observation of banded vegetation should increasingly accompany attempts at modelling responses of global drylands to climate change. [ABSTRACT FROM AUTHOR]

In the paper, the aridity is defined on the basis of four climate indices: De Martonne's index of aridity, Lang's Rain Factor and Gračanin's Rain factor for the vegetation period and hydrothermal coefficient of Seljaninov. While the annual value of the drought index (IDM) shows humid characteristics, the monthly values show the variability of the conditions. The summer months (July and August) are classified as semi-arid months, while the winter months (December- February) are extremely humid. The spatial distribution of the isoarids indicates that the northern part of the basin has the characteristics of a semiarid climate, while the southeastern parts are more humid. The analysis of mean annual values of the drought index indicates in semiarid conditions (1990 and 2000), but also the humid conditions (2005 and 2009). A positive linear trend indicates that there is a tendency towards humid conditions. The significance test confirms the existence of a statistically significant trend. During the vegetation period, semi-arid conditions are present (July- August). April is slightly humid, and October is moderately arid. The Lang's Rain Factor (KFg) characterizes basin climate as semiarid, while the Gračanin rain factor for the vegetation period (KFm) indicates a moisture deficit in the summer months. Hydrothermal coefficient Seljaninova (HTC) indicates a lack of moisture in July and August. Vegetation period is characterized as insufficiently humid. Irrigation is one of the most important measures for solving drought problems, since the yield varies from year to year. [ABSTRACT FROM AUTHOR]

In recent years, climate extreme events have caused increasing direct economic and social losses in the arid region of northwestern China. Based on daily temperature and precipitation data from 1960 to 2010, this paper discussed the linear trend and abrupt changes of climate indices. The general evolution was obtained by the empirical orthogonal function (EOF), the Mann-Kendall test, and the distribution-free cumulative sum chart (CUSUM) test. The results are as follows: (1) climate showed a warming trend at annual and seasonal scale, with all temperature indices exhibiting statistically significant changes. The warm indices have increased, with 1.37%days/decade of warm days (TX90p), 0.17 °C/decade of warmest days (TXx) and 1.97 days/decade of warm spell duration indicator (WSDI), respectively. The cold indices have decreased, with − 1.89%days/decade, 0.65 °C/decade and − 0.66 days/decade for cold nights (TN10p), coldest nights (TNn) and cold spell duration indicator (CSDI), respectively. The precipitation indices have also increased significantly, coupled with the changes of magnitude (max 1-day precipitation amount (RX1day)), frequency (rain day (R0.1)), and duration (consecutive dry days (CDD)). (2) Abrupt changes of the annual regional precipitation indices and the minimum temperature indices were observed around 1986, and that of the maximum temperature indices were observed in 1996. (3) The EOF1 indicated the overall coherent distribution for the whole study area, and its principal component (PC1) was also observed, showing a significant linear trend with an abrupt change, which were in accordance with the regional observation results. EOF2 and EOF3 show contrasts between the southern and northern study areas, and between the eastern and western study areas, respectively, whereas no significant tendency was observed for their PCs. Hence, the climate indices have changed significantly, with linear trends and abrupt changes noted for all climate indices, which will have serious impacts on water resources and ecological environment in the arid region of China. [ABSTRACT FROM AUTHOR]

This paper aims at investigating the effect of combining thermal insulation with high thermal inertia on building’s thermal performance in a hot semi-arid climate. The impacts of these passive techniques on the cooling/heating loads and the indoor comfort are analyzed by means of dynamic simulation as well as on-site monitoring of a two floor detached house located in the Green City of Benguerir in Marrakech region (Morocco). This house, mostly built using local materials, integrates many other passive and hybrid systems. The present study focuses on the hemp-gypsum, the double slab technique for thermal insulation, the double glazing and the high thermal inertia of the walls. Thermal performance of these techniques are assessed by comparison to a hypothetical reference case of the house lacking the considered techniques and built with regular classic construction materials. The results show that the investigated passive systems have a remarkable effect on the indoor air temperature, the thermal comfort and the cooling/heating loads of the building. When the three systems are integrated into the studied house, better comfort conditions are achieved compared to the reference case as its indoor air temperature minimum is up to 5 °C higher in winter while the indoor air temperature maximum is reduced by up to 9 °C in summer. In addition, the daily air temperature amplitude (peak-to-peak difference) is drastically reduced compared to the reference case. Moreover, the discomfort hours based on an acceptable thermal comfort zone of 16 °C–28 °C are reduced by 62% compared to the reference case. Furthermore, the house performs up to 81% of reduction in the annual cooling and heating load compared to the reference case. [ABSTRACT FROM AUTHOR]

This paper reports a comprehensive study on the observed and projected spatiotemporal changes in mean and extreme climate over the arid region of northwestern China, based on gridded observation data and CMIP5 simulations under the RCP4.5 and RCP8.5 scenarios. The observational results reveal an increase in annual mean temperature since 1961, largely attributable to the increase in minimum temperature. The annual mean precipitation also exhibits a significant increasing tendency. The precipitation amount in the most recent decade was greater than in any preceding decade since 1961. Seasonally, the greatest increase in temperature and precipitation appears in winter and in summer, respectively. Widespread significant changes in temperature-related extremes are consistent with warming, with decreases in cold extremes and increases in warm extremes. The warming of the coldest night is greater than that of the warmest day, and changes in cold and warm nights are more evident than for cold and warm days. Extreme precipitation and wet days exhibit an increasing trend, and the maximum number of consecutive dry days shows a tendency toward shorter duration. Multi-model ensemble mean projections indicate an overall continual increase in temperature and precipitation during the 21st century. Decreases in cold extremes, increases in warm extremes, intensification of extreme precipitation, increases in wet days, and decreases in consecutive dry days, are expected under both emissions scenarios, with larger changes corresponding to stronger radiative forcing. [ABSTRACT FROM AUTHOR]

This paper aims at assess district-wise vulnerability index of the state of Karnataka State, which is predominantly is rainfed and is highly susceptible to climatic variability. Secondary data on relevant indicators were collected to prepare indices viz., crop production losses, exposure, sensitivity and adaptive capacity. Following normalization and using appropriate weights for indicators, these four indices were used for constructing vulnerability index, which can be used a rapid assessment method for prioritizing districts that need measures to moderate the detrimental impact of climate change. It has been observed that Climatic variability caused higher production losses in cereals, pulses and oilseeds in Davangere, Gulbarga and Raichur districts, respectively. Districts like Koppal, Raichur, Bijapur Gulbarga, Gadag, Bagalkote and Bellary were placed under extreme degree of exposure. As per the sensitivity index scores, Kolar district is the most sensitive. Further, Bengaluru (Urban), Dakshin Kannada and Kodagu are ranked first, second and third in terms of adaptive capacity in the state. Overall, vulnerability index scores indicate that Gulbarga, Koppal, Raichur, Bellary, Bagalkote, Bijapur and Belgaum are extremely vulnerable districts in the state. It was also estimated that around 70% of the cultivated area, which supports 60% and 67% of livestock and rural population of the state, respectively are facing ‘extreme to high’ level of vulnerability. The ranking based prioritization of the vulnerable areas calls for a holistic approach for each district or a group of districts to reduce their sensitivity, minimize exposure to rainfall variability through implementation of site-specific and leverage adaptive capacity through better health and education facilities, expansion of employment opportunities in other sectors or reducing over dependence on agriculture. [ABSTRACT FROM AUTHOR]

Warming of the climate system is unequivocal, and the change of climate variables will eventually have a great impact on vegetation cover and agricultural practices, especially in the arid area Xinjiang in China, whose agriculture and ecosystems are heavily vulnerable to climate change. In this paper, normalized difference vegetation index (NDVI) was used to study the vegetation growth and its response to climate change in Xinjiang. Firstly, two NDVI datasets (Global Inventory Modeling and Mapping Studies (GIMMS) and Moderate Resolution Imaging Spectroradiometer (MODIS)) were merged through a pixel-wise regression analysis to obtain a long time series of NDVI data, and then, relationships between yearly NDVI and yearly climate variables, and monthly NDVI and monthly climate variables were extensively investigated for grassland and cropland in northern and southern Xinjiang, respectively. Results show the following: (1) there was an increasing trend in NDVI for both grassland and cropland in both northern and southern Xinjiang over the past decades and trends were significant except that for grassland in northern Xinjiang; (2) precipitation and evaporation were more important than temperature for grassland in northern Xinjiang, while precipitation and temperature were more important than evaporation for grassland in southern Xinjiang and cropland in both northern and southern Xinjiang; (3) NDVI was highly correlated with accumulated monthly precipitation instead of monthly precipitation, and there was a lagged effect of precipitation, temperature, and evaporation on NDVI change. However, lagged effects were only significant in specific months. The results could be helpful to agricultural practices; e.g., based on lagged effect of precipitation, irrigation in July is very important for crop growth. [ABSTRACT FROM AUTHOR]

[Display omitted] • As compared to precipitation, soil moisture greatly influences GPP. • There is a solid spatial agreement among PUE and SWUE with a step-wise gradient from southwest to northeast. • PUE and SWUE are relatively low in extremely arid and humid regions. • In relatively moderate areas, PUE and SWUE increase with the abundance of moisture conditions. • Meadow grassland has the highest PUE and SWUE, followed by typical grassland and desert steppe. Grassland ecosystem dominates in the Mongolian Plateau, mostly located in its arid and semi-arid regions. Although the ecosystem is an important source for agriculture, it is also a fragile system ecologically. This system is one of the most sensitive areas to global climate change. Precipitation (PPT) and soil moisture (SM) are important water sources in the grassland ecosystem, and their changes would greatly affect vegetation growth. This paper generates the precipitation use efficiency (PUE) and soil water use efficiency (SWUE) of Mongolian Plateau grassland based on multi-source remote sensing data to investigate the spatio-temporal distribution pattern and identify the driving factors. Results showed four main findings. Firstly, two water use efficiency (WUE) indicators show a generally increasing trend from 2000 to 2018, with average PUE and SWUE 1.07 gC·m−2·mm−1 and 1.03 gC/kg·H 2 O, respectively. They have similar spatial distribution patterns, consistent with the available water resources, decreasing from northeast to southwest. However, grassland vegetation growth is more sensitive to soil moisture than precipitation, and the dynamic change of SWUE is smoother and more significant than PUE. Secondly, due to the higher species richness, better vegetation biological characteristics and less severe growth environment, meadow grassland has the highest PUE and SWUE, followed by typical grassland and desert steppe. Thirdly, PUE and SWUE are relatively low in extremely arid and humid regions. In areas with relatively moderate water conditions (PPT in 148–360 mm, SM in 0.14–0.35 cm3/cm3), two indicators increase with the abundance of moisture conditions and reach the maximum. Fourthly, there is a positive linear relationship between PUE (SWUE) with precipitation and a unimodal correlation between PUE (SWUE) with temperature across the entire grassland. However, a varying correlation exists in different grassland ecosystems, especially meadow grassland. Together with analyzing past and future trends, this study provides strong evidence to reflect the impact of global climate change and the management and protection of the grassland ecosystems in arid and semi-arid regions. [ABSTRACT FROM AUTHOR]

Climate change has been identified as a leading human and environmental crisis of the twenty-first century. Drylands throughout the world have always undergone periods of degradation due to naturally occurring fluctuation in climate. Persistence of widespread degradation in arid and semiarid regions of Iran necessitates monitoring and evaluation. This paper aims to monitor the desertification trend in three types of land use, including range, forest and desert, affected by climate change in Tehran province for the 2000s and 2030s. For assessing climate change at Mehrabad synoptic station, the data of two emission scenarios, including A2 and B2, were used, utilizing statistical downscaling techniques and data generated by the Statistical DownScaling Model (SDSM). The index of net primary production (NPP) resulting from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images was employed as an indicator of destruction from 2001 to 2010. The results showed that temperature is the most significant driving force which alters the net primary production in rangeland, forest and desert land use in Tehran province. On the basis of monitoring findings under real conditions, in the 2000s, over 60% of rangelands and 80% of the forest were below the average production in the province. On the other hand, the long-term average changes of NPP in the rangeland and forests indicated the presence of relatively large areas of these land uses with a production rate lower than the desert. The results also showed that, assuming the existence of circumstances of each emission scenarios, the desertification status will not improve significantly in the rangelands and forests of Tehran province. [ABSTRACT FROM AUTHOR]

As an important part of the global ecosystem, wetlands and their dynamics greatly influence regional eco-environment systems. To understand the distributions, change processes and temporal-spatial characteristics of the wetlands of the inland river basin in an arid region (Heihe River Basin, HRB), this paper employed multi-source remote sensing data to facilitate multi-temporal monitoring of the HRB wetland using a wetland information extraction method. First, we performed monitoring of these wetlands for the years 2000, 2007, 2011 and 2014; then, we analyzed the variation characteristics of the spatial-temporal dynamics of the wetlands in the HRB over the last 15 years via the landscape dynamic change model and the transformation matrix. In addition, we studied the possible driving mechanisms of these changes. The research results showed that the total area of the HRB wetlands had decreased by 2959.13 hectares in the last 15 years (Since 2000), and the annual average loss was 1.09%. The dynamics characterizing the HRB wetlands generally presented a trend of slow increase after an initial decrease, which can be classified into three stages. From 2000 to 2007, the total wetland area rapidly decreased; from 2007 to 2011, the area slowly decreased; and from 2011 to 2014, the area gradually increased. The dynamic changing processes characterizing the wetland resources were ascribed to a combination of natural processes and human activities. The main driving mechanisms of wetland dynamic changes include climatic conditions, upper reach water inflows, population, water resources, cultivated area, and policy. The findings of this study can served as reference and support for the conservation and management of wetland resources in the HRB. [ABSTRACT FROM AUTHOR]

Changes in climate and land cover are among the principal variables affecting watershed hydrology. This paper uses a cell-based model to examine the hydrologic impacts of climate and land-cover changes in the semi-arid Lower Virgin River (LVR) watershed located upstream of Lake Mead, Nevada, USA. The cell-based model is developed by considering direct runoff based on the Soil Conservation Service - Curve Number (SCS-CN) method and surplus runoff based on the Thornthwaite water balance theory. After calibration and validation, the model is used to predict LVR discharge under future climate and land-cover changes. The hydrologic simulation results reveal climate change as the dominant factor and land-cover change as a secondary factor in regulating future river discharge. The combined effects of climate and land-cover changes will slightly increase river discharge in summer but substantially decrease discharge in winter. This impact on water resources deserves attention in climate change adaptation planning. Editor Z.W. Kundzewicz [ABSTRACT FROM AUTHOR]

This study focuses on extreme precipitation changes in Xinjiang Province of Northwest China, which has experienced an increase in climate disasters in recent years. This paper investigates extreme precipitation events in Xinjiang, using 54 stations with daily precipitation records from the period 1961–2008. Different statistical tests and approaches were used to check the significance of trends of single and Xinjiang regionally aggregated precipitation series for intensity and in frequency. There were predominantly positive trends in annual maximum precipitation and a remarkable increment in the frequency of extreme precipitation over certain thresholds (from 10 to 40 mm). Although the series of frequencies exceeding thresholds had positive trends, only a minority were statistically significant. This lack of significance is because of the high variability of extreme precipitation in space and time. Thus, significant trends were evident when we assessed the extreme precipitation indicators of intensity and frequency at the regional level, both in intensity and frequency over thresholds, with a clearer signal in Xinjiang. [ABSTRACT FROM AUTHOR]

The arid region of Northwest China, located in the central Asia, responds sensitively to global climate change. Based on the newest research results, this paper analyzes the impacts of climate change on hydrology and the water cycle in the arid region of Northwest China. The analysis results show that: (1) In the northwest arid region, temperature and precipitation experienced “sharply” increasing in the past 50 years. The precipitation trend changed in 1987, and since then has been in a state of high volatility, during the 21st century, the increasing rate of precipitation was diminished. Temperature experienced a “sharply” increase in 1997; however, this sharp increasing trend has turned to an apparent hiatus since the 21st century. The dramatic rise in winter temperatures in the northwest arid region is an important reason for the rise in the average annual temperature, and substantial increases in extreme winter minimum temperature play an important role in the rising average winter temperature; (2) There was a significant turning point in the change of pan evaporation in the northwest arid area in 1993, i.e., in which a significant decline reversed to a significant upward trend. In the 21st century, the negative effects of global warming and increasing levels of evaporation on the ecology of the northwest arid region have been highlighted; (3) Glacier change has a significant impact on hydrology in the northwest arid area, and glacier inflection points have appeared in some rivers. The melting water supply of the Tarim River Basin possesses a large portion of water supplies (about 50%). In the future, the amount of surface water will probably remain at a high state of fluctuation. [ABSTRACT FROM AUTHOR]

Destocking degraded rangeland can potentially help climate change mitigation by re-sequestering emitted carbon. Broad-scale implementation has been limited by uncertainties in the magnitude, duration and location of sequestration and the profitability relative to the existing grazing land use. This paper employs a novel methodology to assess potential rangeland sequestration and its profitability, using 31 Mha of rangeland in New South Wales, Australia as a case-study. This approach combines remotely sensed data and modelled estimates of various components. Remotely sensed, synthetic aperture radar data were used to determine woody biomass of minimally degraded forest (benchmarks) and neighbouring more-degraded forest, followed by sequestration modelling using non-linear growth rates based on woody thickening and slow-growing plantations, scaled to the benchmarks. Livestock concentration and livestock-based farm profits were modelled. We compared sequestration and grazing net profits, for a carbon price of AUD$10 Mg −1 CO 2 -e, at different growth stages for different levels of forest attrition. We found that broad-scale destocking with subsequent C re-sequestration was initially unprofitable compared with grazing. However, after 50 years, with full costing of C emissions, the returns were similar for the two alternatives of continued grazing or re-sequestration, for areas with biomass below benchmark levels. Reforestation of recently deforested land represents the most profitable option with profitability increasing with growth rate. Emissions of soil organic carbon, set in motion by climate change over the next century, were calculated to be the largest of all sources. Emissions from biomass, induced by climate change, will be higher where vegetation cannot adapt. The secondary effects of climate change will reduce re-sequestration and grazing profits, possibly limiting the carbon stored by re-sequestration projects. [ABSTRACT FROM AUTHOR]

Coastal aquifers represent an important source of freshwater in arid and semi-arid regions. The increased extraction from coastal aquifers decreases the freshwater spilled out to the sea. Consequently, seawater intrusion increases inland and wells become contaminated. Nile delta aquifer in Egypt is one of these aquifers which subject to sever seawater intrusion from Mediterranean Sea. Saltwater intrusion is considered one of the main processes t hat degrade water- quality by raising salinity. It may occur due to human activities and /or by natural events. Over- pumping is considered the main cause of saltwater intrusion. Moreover, sea level rise accelerates saltwater intrusion. Due to climate change, it is expected a rise in temperature which would lead to an increase in the rates of evaporation and this will be accompanied by decrease in water level of the Nile, also this change would lead to sea level rise (SLR) .A result to rise in population intensity and expected shortage in surface water would lead to an increase of extraction rate from groundwater. In this paper 3-D model (SEAWAT) is used to study sea water intrusion in Nile delta aquifer considering different scenarios, the first scenario is the increase of sea level by 25, 50 and 100 cm, the second is to decrease the surface water system by 25, 50 and 100 cm, the third is to increase the extraction rate by 25, 50 and 100 % and fourth scenario is a combination of while the three scenarios. The results show that saltwater intrusion in East Nile delta reach 76.25 km from shore line for base case, but reaches to 79.25 km, 79 km, 82 km and 83 km for Equiconcentration line 35 and reaches to 92.25 km, 92 km, 91.75 km and 92.75 km for scenarios1, 2, 3 and 4 respectively after 100 year for Equiconcentration line 1.00. It is also observed that salt water intrusion in the Middle reaches to 63.75 km from shore line for base case, but reaches to 67. 75 km, 67.25 km, 65.75 km and 67.50 km for Equiconcentration line 3 5 and reaches to 97 km, 97.50 km, 107.75 km and 110 km for scenarios1, 2, 3 and 4 respectively after 100 year for Equiconcentration line 1.00. It is clear that saltwater intrusion in the West reaches to 48.00 km from shore line for base case, but reaches to 49.00 km, 48.75 km, 45.50 km and 47.7 5 km for Equiconcentration line 35 and reaches to 73.75 km, 74 km, 79.50 km and 79.50 km for scenarios 1, 2, 3 and 4 respectively after 100 year for Equiconcentration line 1.00. Finally increasing SLR or decreasing recharge from [ABSTRACT FROM AUTHOR]

In comparison with drylands elsewhere, the unpredictability of rainfall in central Australia is globally distinctive. The transformative rhythms of arid Australia reflect extremes of climatic conditions rather than seasons, and are characterized by irregular pulses of productivity that punctuate long periods of drought. These decadal-scale dynamics are only now beginning to be understood. Further complications in predicting and managing the biological processes within these landscapes arise from the vast spatial extent of arid and semi-arid communities, and increasing recognition of the heterogeneities that drive the formation of patterns across multiple scales. In 2010 and 2011 flooding rains broke long-standing rainfall records and triggered an anticipated greening of the typically dry red landscapes of central Australia. These unusual climatic events provided an unparalleled opportunity to test ideas about productivity and function, bottom-up versus top-down effects, and differential responses of biota that reflect landscape connections and heterogeneity. Migrations of species outside their known ranges, irruptions of rodents and redistribution of resources are just a few of the novel observations that were reported. The transformation of the landscape also presented land managers with challenges stemming from the influx of invasive species that trigger novel ecological interactions and processes. The papers presented in this special issue describe how ecologists and managers responded to the unprecedented rainfall events, key lessons that we have learnt, and practical recommendations on how to improve conservation outcomes for the fragile inland environment into the future. [ABSTRACT FROM AUTHOR]

The southeastern Chinese Loess Plateau is the terminal deposition area of dusts transported by the East Asian winter monsoon and the frontal area penetrated by the East Asian summer monsoon, and thus a climate sensitive region. This paper reports a rock magnetic study of a Quaternary loess-paleosol section in such a region. We tried to reconstruct the paleoclimate evolution history in the region during 1.95-0.40 Ma with magnetic parameters. The results show a general up-section decreasing trend of the ratio of HIRM/(SIRM-IRM), indicating a long-term decreasing trend of hematite coercivities in the deposits, which can be mainly related to the cooling and aridification trend of the environment in interglacial depositional area and glacial dust source region. The ratio, χ/ χ, widely used to reflect the variations of magnetic mineral grain size, manifests a long-term increasing trend of the magnetic mineral grain size and tends to indicate an overall weakening trend of the East Asian summer monsoon that controlled the pedogenic intensity. Although the regional multi-segmented paleoclimatic records revealed by several magnetic parameters in our study, the long-term Asian cooling and aridification trend inferred here is of global correlation significance. [ABSTRACT FROM AUTHOR]

Hydrological processes in most semiarid regions on Earth have been changing under the impacts of climate change, human activities, or combinations of the two. This paper first presents a trend analysis of the spatiotemporal changes in water resources and then diagnoses their underlying atmospheric and socio-economic causes over 10 catchments in the Laoha basin, a typical semiarid zone of northeast China. The impacts of climate variability and human activities on streamflow change were quantitatively evaluated by the VIC (Variable Infiltration Capacity) model. First, results indicate that six out of the 10 studied catch-ments have statistically significant downward trends in annual streamflow; however, there is no significant change of annual precipitation for all catchments. Two abrupt changes of annual streamflow at 1979 and 1998 are identified for the four largest catchments. Second, the Laoha basin generally experienced three evident dry-wet pattern switches during the past 50 years. Furthermore, this basin is currently suffering from unprecedented water shortages. Large-scale climate variability has affected the local natural hy-drologie system. Third, quantitative evaluation shows human activities were the main driving factors for the streamflow reduction with contributions of approximately 90% for the whole basin. A significant in-crease in irrigated area, which inevitably resulted in tremendous agricultural water consumption, is the foremost culprit contributing to the dramatic runoff reduction, especially at midstream and downstream of the Laoha basin. This study is expected to enable policymakers and stakeholders to make well-informed, short-term practice decisions and better plan long-term water resource and ecoenvironment management strategies. [ABSTRACT FROM AUTHOR]

Mesoscale Convective Systems (MCSs) over the southern Arabian Peninsula are more common during the spring months of March and April. In this paper, the processes behind such severe convective events and their local-scale impacts are investigated using reanalysis data, satellite-derived and observational products. The analysis of 95 MCS events from 2000 to 2020 revealed that they are triggered by low-level wind convergence and moisture advection from the Arabian Sea, Arabian Gulf and/or Red Sea. An equatorward displacement and strengthening of the subtropical jet also precondition the environment, as does the presence of a mid-level trough. The latter is generally part of a large-scale pattern of anomalies that are equivalent barotropic in nature, and therefore likely a response to tropical or subtropical forcing. At more local-scale, a drying of the mid-troposphere between 850 and 250 hPa typically by 50%, a reduction of the upper-level winds by about 5 m s−1, and an increase in the upper-tropospheric temperature on average by 2–3 K, are typically observed during MCS events. Over the 21-year period, a statistically significant increase in the MCSs' duration over southeast Arabian Peninsula has been found, suggesting that such extreme events may be even more impactful in a warming world. • MCSs over the southern Arabian Peninsula occur more frequently in March and April months. • Preconditioning and triggering processes for MCSs over this region are investigated. • Over the 20-year period, MCSs have been lasting longer over the UAE. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this paper is to study the spatial and temporal variability of the Aridity Index (AI) in Greece, per decade, during the 50-year period (1951–2000). Besides, the projected changes in ensemble mean AI between the period 1961–1990 (reference period) and the periods 2021–2050 (near future) and 2071–2100 (far future) along with the inter-model standard deviations were presented, based on the simulation results, derived from a number of Regional Climatic Models (RCMs), within the ENSEMBLE European Project. The projection of the future climate was done under SRES A1B. The climatic data used, concern monthly precipitation totals and air temperature from 28 meteorological stations (22 stations from the Hellenic National Meteorological Service and 6 stations from neighboring countries, taken from the Monthly Climatic Data for the World). The estimation of the AI was carried out based on the potential evapotranspiration (PET) defined by Thornthwaite (1948). The data processing was done by the application of the statistical package R-project and the Geographical Information Systems (GIS). The results of the analysis showed that, within the examined period (1951–2000), a progressive shift from the “humid” class, which characterized the wider area of Greece, towards the “sub-humid” and “semi-arid” classes appeared in the eastern Crete Island, the Cyclades complex, the Evia and Attica, that is mainly the eastern Greece. The most significant change appears during the period 1991–2000. The future projections at the end of twentieth century, using ensemble mean simulations from 8 RCMs, show that drier conditions are expected to establish in regions of Greece (Attica, eastern continental Greece, Cyclades, Dodecanese, eastern Crete Island and northern Aegean). The inter-model standard deviation over these regions ranges from 0.02 to 0.05 against high values (0.09–0.15) illustrated in western mountainous continental Greece, during 2021–2050. Higher values of inter-model standard deviation appear in the 2071–2100 ranging from 0.02 to 0.10 reaching even 0.50 over mountainous regions of the country. [Copyright &y& Elsevier]

The majority of the world's population growth to 2050 is projected to occur in the tropics. Hence, there is a serious need for robust methods for undertaking water resource assessments to underpin the sustainable management of water in tropical regions. This paper describes the largest and most comprehensive assessment of the future impacts of runoff undertaken in a tropical region using conceptual rainfall-runoff models (RRMs). Five conceptual RRMs were calibrated using data from 115 streamflow gauging stations, and model parameters were regionalized using a combination of spatial proximity and catchment similarity. Future rainfall and evapotranspiration projections (denoted here as GCMES) were transformed to catchment-scale variables by empirically scaling (ES) the historical climate series, informed by 15 global climate models (GCMs), to reflect a 1°C increase in global average surface air temperature. Using the best-performing RRM ensemble, approximately half the GCMES used resulted in a spatially averaged increase in mean annual runoff (by up to 29%%) and half resulted in a decrease (by up to 26%%). However, ~70%% of the GCMES resulted in a difference of within ±5%% of the historical rainfall (1930-2007). The range in modeled impact on runoff, as estimated by five RRMs (for individual GCMES), was compared to the range in modeled runoff using 15 GCMES (for individual RRMs). For mid- to high runoff metrics, better predictions will come from improved GCMES projections. A new finding of this study is that in the wet-dry tropics, for extremely large runoff events and low flows, improvements are needed in both GCMES and rainfall-runoff modeling. [ABSTRACT FROM AUTHOR]

Abstract: The combined impact of global climate change and increasing human activities has led to the severe deterioration of grasslands in China. Using the solar irrigation systems is an effective way for sustaining pasture lands in arid regions. A solar irrigation system is the device that uses the solar cell from the sun’s radiation to generate electricity for driving the pump. And photovoltaic pump consists of an array of photovoltaic cells and pumps water from a well or reservoir for irrigation. Although ecologists and organizations constantly work and find ways to conserve grasslands through irrigation systems that use solar energy, issues on water resources are not yet thoroughly discussed. This paper takes into account the main factors in the study of water resources, including precipitation and groundwater, to analyze the feasibility of using a photovoltaic (PV) pumping irrigation. The appropriate area for such a PV pumping irrigation in Qinghai Province is also presented. The results show that the grasslands appropriate for PV pumping cover about 8.145millionha, accounting for 22.3% of the grasslands in the entire province. Finally, the problems and countermeasures of PV pumping irrigation, including the impact on regional water balance, groundwater level and highland permafrost, are also considered. [Copyright &y& Elsevier]

In this paper, we aim to investigate how local communities cope with and adapt to multiple stresses in rural semiarid South Africa. In semiarid regions water scarcity is one of a number of stresses that shape livelihood vulnerability. With climate change, it is predicted that rainfall in South Africa will become more uncertain and variable in the future, exposing more people to water insecurity. At the same time, the impacts of disease, a lack of institutional capacity, and limited livelihood opportunities can combine to limit adaptive capacity. Therefore, adaptation to changing climate should not be viewed in isolation but instead in the context of social, economic, and political conditions, all of which shape local community vulnerability and people's ability to cope with and adapt to change. This study uses a qualitative-quantitative-qualitative framework, including the use of a stated preference survey, to identify the drivers of agroecosystem change, to understand the capacity of households to cope with droughts, and to determine the ability of local institutions to respond to crises. The analysis suggests that the capacity of the agroecosystem to remain productive during droughts is decreasing, individual/household adaptive capacity remains low, and institutional capacity faces considerable barriers that prevent it from supporting households to adapt to multiple stresses. This research adds weight to the claim that vulnerability reflects multiple forces and processes, and that multiple stresses, that are agroecological, socioeconomic, and institutional in nature, need to be examined to understand vulnerability and to prevent maladaptation. [ABSTRACT FROM AUTHOR]

Climate change and expected weather patterns in the long-term threaten the livelihood inside oases settlements in arid lands, particularly under the recurring heat waves during the harsh months. This paper investigates the impact of climate change on the outdoor thermal comfort within a multifamily housing neighborhood that is considered the most common residential archetype in Algerian Sahara, under extreme weather conditions in the summer season, in the long-term. It focuses on assessing the outdoor thermal comfort in the long-term, based on the Perceived Temperature index (PT), using simulation software ENVI-met and calculation model RayMan. Three different stations in situ were conducted and combined with TMY weather datasets for 2020 and the IPCC future projections: A1B, A2, B1 for 2050, and 2080. The results are performed from two different perspectives: to investigate how heat stress evolution undergoes climate change from 2020 till 2080; and for the development of a mathematical algorithm to predict the outdoor thermal comfort values in short-term, medium-term and long-term durations. The results indicate a gradual increase in PT index values, starting from 2020 and progressively elevated to 2080 during the summer season, which refers to an extreme thermal heat-stress level with differences in PT index averages between 2020 and 2050 (+5.9 °C), and 2080 (+7.7 °C), meaning no comfortable thermal stress zone expected during 2080. This study gives urban climate researchers, architects, designers and urban planners several insights into predicted climate circumstances and their impacts on outdoor thermal comfort for the long-term under extreme weather conditions, in order to take preventive measures for the cities' planning in the arid regions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Grassland degradation is the main reason for the decline in carbon storage. • The carbon storage of farmland has increased significantly. • The risk of carbon storage reduction in the future is still high. The carbon storage of terrestrial ecosystems is closely related to global climate change. Therefore, assessing the impact of land-use changes on carbon storage is instructive to reduce global carbon emissions. Taking an arid region in northwest China as an example, this paper analyzed the land-use changes in arid region from 1980 to 2015. It used the CA-Markov model to predict the land-use pattern from 2020 to 2050, the carbon storage and sequestration module in Integrated Valuation of Ecosystem Services and Tradeoffs (Invest) mode to assess and predict ecosystem carbon storage over the past 35 years and in the next 30 years and discusses the impact of land-use changes on the carbon storage of terrestrial ecosystems. The results showed that: (1) The high-value areas of carbon storage in arid region were primarily concentrated in grassland, forests and farmland, and the low-value areas of carbon storage were mainly in desert areas. (2) The carbon storage in arid region showed a downward trend. From 1980 to 2015, the carbon reserves of terrestrial ecosystems in arid region decreased by 90.95 Tg, and the net loss of carbon reserves from 2020 to 2050 was 14.72 Tg. Grassland degradation was the main reason for the reduction of carbon storage in arid region. (3) The carbon storage of farmland had increased significantly, but the expansion of farmland dominated by high carbon density grassland, wetland and forest, had reduced the overall carbon storage of the arid region. [ABSTRACT FROM AUTHOR]

Because land surface emissivity (ℇ) has not been reliably measured, global climate model (GCM) land surface schemes conventionally set this parameter as simply constant, for example, 1 as in the National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Prediction (NCEP) model, and 0.96 for bare soil as in the National Center for Atmospheric Research (NCAR) Community Land Model version 2 (CLM2). This is the so-called constant-emissivity assumption. Accurate broadband emissivity data are needed as model inputs to better simulate the land surface climate. It is demonstrated in this paper that the assumption of the constant emissivity induces errors in modeling the surface energy budget, especially over large arid and semiarid areas where ℇ is far smaller than unity. One feasible solution to this problem is to apply the satellite-based broadband emissivity into land surface models. The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument has routinely measured spectral emissivities (ℇλ) in six thermal infrared bands. The empirical regression equations have been developed in this study to convert these spectral emissivities to broadband emissivity (ℇ) required by land surface models. The observed emissivity data show strong seasonality and land-cover dependence. Specifically, emissivity depends on surface-cover type, soil moisture content, soil organic composition, vegetation density, and structure. For example, broadband ℇ is usually around 0.96–0.98 for densely vegetated areas [(leaf area index) LAI > 2], but it can be lower than 0.90 for bare soils (e.g., desert). To examine the impact of variable surface broadband emissivity, sensitivity studies were conducted using offline CLM2 and coupled NCAR Community Atmosphere Models, CAM2–CLM2. These sensitivity studies illustrate that large impacts of surface ℇ occur over deserts, with changes up to 1°–2°C in ground temperature, surface skin temperature, and 2-m surface air temperature, as well as evident changes in sensible and latent heat fluxes. [ABSTRACT FROM AUTHOR]

The area–time integral (ATI) method has previously been successfully used to estimate the area-averaged rain-rate distribution and the rainfall volume over an area from radar or from satellite infrared (IR) data. In most cases, the method was implemented over regions or test areas with an assumed homogeneous climatic character, that is, without a strong spatial variation of the rain regime throughout the test area. In the present paper, the behavior of the ATI method is discussed for a test area displaying two strong gradients of the cumulative annual rainfall: one meridional, at the transition between regions having, respectively, a desertic and an equatorial climate and the other zonal, at the transition between land and sea. The studied area is divided into four subtest areas (north, south, land, and sea) over which the ATI computation is applied separately. The linear coefficient relating the radar-observed area-averaged rain rate and the fractional area where the rain is higher than a threshold calculated over the four subtest areas is found to be almost constant, in agreement with the ergodic character of the rain-rate distribution observed in this region. Similarly, the linear coefficient relating the rain volume over the subtest areas to the IR satellite-derived ATI, a parameter analogous to the Geostationary Operational Environmental Satellite (GOES) Precipitation Index (GPI), is found to be very steady, with a mean value of 3.02 mm h-1 and a coefficient of variation of only 8%. These coefficients, as well as the underlying dynamic and microphysical processes, do not seem significantly influenced by the climatic character, even at a short space scale, in the studied area. The ratio of radar rain areas to cloud areas is, notably, almost constant. For a brightness temperature of 235 K, the ratio of the cloud area to rain area is around 1.68. [ABSTRACT FROM AUTHOR]

Climate variability and change coupled with small landholdings, low land productivity and water scarcity in arid and semi-arid regions contribute to environmental degradation, reduced agricultural productivity, and increased vulnerability to the rural communities. With the aid of the fuzzy cognitive maps constructed by 427 community groups with 4–5 members in each group, drawn from 96 villages in 12 districts of arid and semi-arid India, the paper evaluates the effectiveness of various adaptation pathways. The ongoing adaptations in arid and semi-arid India face adaptation deficits. The FCM-based simulations revealed that integrated adaptation measures that embrace nature-based solutions, including integrated water resource management, natural farming-assisted soil rejuvenation, and improved agricultural productivity are most likely to enhance the resilience of small and marginalised farming communities to climate variability and change. Facilitation of such adaptation measures requires inclusive and adaptive local institutions, sufficient financial assistance, and climate information services. Besides, gender-nuanced, inclusive, and adaptive governance and processes would be helpful for the implementation of appropriate adaptation interventions in arid and semi-arid drylands worldwide. Hence policy-makers must enable polycentric and adaptive governance, and inclusive institutions and processes. The emphasis on multiple factors in a socio-ecological system often makes it difficult to understand the critical role of a particular factor. However, the FCM-based simulations in this study helped us overcome such limitations. Image 1 • FCM-based simulations used to examine the effectiveness of current adaptations. • Current adaptations face adaptation deficit and provide limited resilience. • Integrated adaptations embracing nature-based solutions could provide resilience. • Lack of finance, technology, and locally relevant information are the key barriers. • Polycentric-adaptive governance and inclusive institutions & processes are crucial. [ABSTRACT FROM AUTHOR]

This review paper compiles research related to debris flows and hyperconcentrated flows in the central Andes (30°–33° S), updating the knowledge of these phenomena in this semiarid region. Continuous records of these phenomena are lacking through the Andean region; intense precipitations, sudden snowmelt, increased temperatures on high relief mountain areas, and permafrost degradation are related to violent flow discharges. Documented catastrophic consequences related to these geoclimatic events highlight the need to improve their understanding in order to prepare the Andean communities for this latent danger. An amplified impact is expected not only due to environmental changes potentially linked to climate change but also due to rising exposure linked to urban expansion toward more susceptible or unstable areas. This review highlights as well the need for the implementation of preventive measures to reduce the negative impacts and vulnerability of the Andean communities in the global warming context. [ABSTRACT FROM AUTHOR]

Optimization of the urban landscape composition and configuration through initiative planning is important to sustainable development of the drylands of northern China (DNC). Taking the agro-pastoral transitional zone of northern China (APTZNC) as an example, this paper developed an approach of sustainable urban landscape planning (SULP) under the stress of climate change in the DNC. First, we quantify the amount of water resources under the future climate change impacts (CCI). Then, we adjust the urban land area based on water resources carrying capacity constraints. Finally, we use the LUSD-urban (Land Use Scenario Dynamics-urban) model to adjust the configuration of the urban landscape to avoid occupying important natural habitats and corridors, prime croplands, and floodplains. We find that the SULP can effectively mitigate the comprehensive effects of regional urban landscape dynamics on water resources, food security, ecological security, and flood risks. By performing the SULP, prime croplands, floodplains, and important natural habitats and corridors occupied by urban land will decrease by 2,187 km2, 750 km2, and 130 km2, respectively, during the period of 2015–2050 in the APTZNC. We also find that the proposed approach can effectively manage the impacts of climate change on water resource capacity and reduce water stress of the entire APTZNC and its sub-regions. Thus, the proposed SULP approach and the experiences from the case study in the APTZNC are helpful for guiding urban landscape planning to achieve sustainable development of cities in the DNC and even in the drylands around the world. • Sustainable urban landscape planning under the stress of climate change was performed. • Urban land area was adjusted based on water resources carrying capacity constraints. • Urban landscape configuration was adjusted to avoid occupying important areas. • The planning can mitigate the comprehensive effects of urban landscape dynamics. • Addressing the climate change impacts should be incorporated into urban landscape planning. [ABSTRACT FROM AUTHOR]

The climate instability (millennial-scale rapid climatic oscillations) during the last glacial period has been a hot issue in Quaternary paleoclimate cycle, however, the driving mechanism and involved areas are still unclear. Previous reports mainly came from Green ice cores, North Atlantic deep-sea sediments and loess, stalagmites, lake records in the East Asian monsoon area, however, evidences from the Asian interior arid regions are scarce. Central Asia is distant from oceanic moisture sources and the climate is dominated by the Westerlies and the Subtropical High. Late Pleistocene loess sediments sporadically distributed at the pediments, terraces and basins provide us an opportunity to verify the existence of millennial-scale climatic fluctuations in Central Asia and understand the relations between high-low latitude climate. During the last decades, we have carried lots of loess investigations in Central Asian mainly around the Tienshan Mountains including Xinjiang in China, Kazakhstan, Kyrgyzstan and Tajikistan. In this paper, we report the preliminary results of loess investigations, and divide the loess distribution in Central Asia into three zones, which correspond to different hydrothermal combination conditions; and coupled with previous literatures, we review the progress of paleoclimate study of loess especially chronology in Central Asia, analyze problems of the last glacial climate events in Central Asia, and discusses its process and mechanism. Up to now, paleoclimatic proxies like grain size, mineralogy and geochemistry confirmed that that there are indeed millennial-scale rapid oscillations during the last glacial period in Central Asia, but they are inconsistent in age and variability. These rapid changes may be related to the following aspects: (a) contraction and expansion of the ice sheet in the high latitudes region of North Atlantic, (b) changes in the intensity and extent of the Siberian high pressure which further lead to the variance in wind dynamics, (c) and the north-south migration of the mid-latitude westerlies. The solar radiation is not the main driving factor for the rapid changes in Central Asia. [ABSTRACT FROM AUTHOR]

In semi-arid regions of the world, knowledge about the long-term hydroclimate variability is essential to analyze and evaluate the impact of current climate change on ecosystems. We present the first tree-ring δ18O based hydroclimatic reconstruction for northern semi-arid Iran spanning the period 1515–2015. A highly significant correlation between tree-ring δ18O variations of juniper trees and spring (April–June) precipitation reveals a major influence of spring water availability during the early growing season. The driest period of the past 501 years occurred in the 16th century while the 18th century was the wettest, during which the overall highest frequency of wet year events occurred. A gradual decline in spring precipitation is evident from the beginning of the 19th century, pointing to even drier climate conditions. The analysis of dry/wet events indicates that the frequency of years with relatively dry spring increased over the last three centuries, while the number of wet events decreased. Our findings are in accordance with historical Persian disaster records (e.g., the severe droughts of 1870–1872, 1917–1919; severe flooding of 1867, the 1930s, and 1950). Correlation analyses between the reconstruction and different atmospheric circulation indices revealed no significant influence of large-scale drivers on spring precipitation in northern Iran. [ABSTRACT FROM AUTHOR]