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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 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]

The effects of climate change in Uganda are manifested by severe and sometimes extreme weather events such as droughts and landslides. An Integrated Watershed Management (IWM) plan was initiated in the Karamoja region, aimed at generating information that could be used to reduce climate vulnerabilities among the rural poor. The study aimed at determining the local community's perception of the effects of climate change on their livelihoods; and, to examine the effectiveness of the Integrated Watershed Management practices (IWMPs) on agricultural production within the area. Three hundred and ninety-seven households were randomly chosen and included in the survey. Interviews with local government officials who held high posts were conducted. Direct observations were also used for data collection. Findings showed that droughts and increases in pests and diseases; were some of the impacts caused by climate change events. Despite the initiation of IWMPs, climate change events moderately increased food insecurity (γ = 0.556; P=0.000) and also moderately affected community assets like roads and valley dams (γ = 0.426; P=0.000). In addition, household income insecurity was moderately and positively related to climate change effects (γ = 0.556; P=0.000). A weak positive relationship was found between the application of IWMPs and agricultural production (γ = 0.273; P=0.000). The Uganda Government should emphasize and intensify the implementation of IWMPs among the farmers living in agricultural watersheds as a means of continuously improving agricultural production and building the farmers' resilience to climate change events. [ABSTRACT FROM AUTHOR]

This paper explores current and future issues of water availability and use in one of the world's major wine-producing areas, Mendoza Province in Argentina. The region is located close to the Central Andes and is characterized by an arid to semi-arid climate, which exacerbates pressures on land-use and water resources for wine production. The principal supply of water originates in the snow and ice fields of the nearby Andean peaks. Already under stress today, the environmental, economic and societal structure of the region, highly dependent on the wine industry, is likely to be vulnerable to climate change in the course of the 21st century. In this study, the possible impacts of shifting temperature and precipitation patterns and climate variability linked to extreme events and El Niño/Southern Oscillation ENSO on water resources in the region and consequently on the wine industry will be investigated. While climatic factors already today exert a major control on water availability, water use is also shown to be influenced by non-climatic factors, in particular overexploitation of the resource and a certain degree of opacity of policies related to water rights and water allocation. Climate model results for the future suggest that there may be important changes in the quantity and timing of stream flow, highly dependent on the Andean cryosphere where many glaciers are already rapidly shrinking today. The direct impacts of a changing climate on wineries include extreme events and also decreased water availability for irrigation in the long term. In view of the importance wine as a major income-earner for Argentina, public water policies will need to address both the issues of unreliable current water governance practices and the adaptations necessary to cope with a changing climate. [ABSTRACT FROM AUTHOR]

The major tributary of the lower Colorado River, the Gila River, is a critical source of water for human and natural environments in the southwestern United States. Warmer and drier than the upper Colorado River basin, with less snow and a bimodal precipitation regime, the Gila River is controlled by a set of climatic conditions that is different from the controls on upper Colorado River flow. Unlike the Colorado River at Lees Ferry in Arizona, the upper Gila River and major Gila River tributaries, the Salt and Verde Rivers, do not yet reflect significant declines in annual streamflow, despite warming trends. Annual streamflow is dominated by cool-season precipitation, but the monsoon influence is discernable as well, variable across the basin and complicated by an inverse relationship with cool-season precipitation in the Salt and Verde River basins. Major multiyear streamflow droughts in these two basins have frequently been accompanied by wet monsoons, suggesting that monsoon precipitation may partially offset the impacts of a dry cool season. While statistically significant trends in annual streamflow are not evident, decreases in autumn and spring streamflow reflect warming temperatures and some decreases in spring precipitation. Because climatic controls vary with topography and the influence of the monsoon, the impact of warming on streamflow in the three subbasins is somewhat variable. However, given relationships between climate and streamflow, current trends in hydroclimate, and projections for the future, it would be prudent to expect declines in Gila River water supplies in the coming decades. Significance Statement: This research investigates the climatic controls on the Gila River and its major tributaries, the Verde and Salt Rivers, to gain insights on how trends in climate may impact future water supply. The Gila River is the major tributary of the lower Colorado River, but, unlike the situation for the upper Colorado River, no significant decreasing trends in annual streamflow are evident despite warming temperatures. Climate–streamflow relationships are more complex in this part of the Colorado River basin, and several factors may be buffering streamflow to the impact of warming. However, given the key climatic controls on streamflow, current and emerging trends in climate, and projections for the future, declines in streamflow should be expected in the future. [ABSTRACT FROM AUTHOR]

Declines in terrestrial water storage (TWS) exacerbate regional water scarcity and global sea level rise. Increasing evidence has shown that recent TWS declines are substantial in ecologically fragile drylands, but the mechanism remains unclear. Here, by synergizing satellite observations and model simulations, we quantitatively attribute TWS trends during 2002–2016 in major climate zones to three mechanistic drivers: climate variability, climate change, and direct human activities. We reveal that climate variability had transitory and limited impacts (<20%), whereas warming‐induced glacier loss and direct human activities dominate the TWS loss in humid regions (∼103%) and drylands (∼64%), respectively. In non‐glacierized humid areas, climate variability generated regional water gains that offset synchronous TWS declines. Yet in drylands, TWS losses are enduring and more widespread with direct human activities, particularly unsustainable groundwater abstraction. Our findings highlight the substantive human footprints on the already vulnerable arid regions and an imperative need for improved dryland water conservation. Plain Language Summary: Terrestrial water storage (TWS) losses are increasingly prominent in both global and regional scales, particularly in vulnerable drylands. An accurate attribution of TWS changes is essential for the sustainability and conservation of water resources. We provide a comprehensive interpretation of recent satellite‐observed TWS changes in each climate zone through quantitative attributions to natural and anthropogenic factors. We found climate change and direct human activities are the dominant drivers of zonal TWS changes but their impacts are considerably divergent between drylands and humid regions. In humid regions, TWS losses are primarily concentrated on glacierized regions and the net TWS budget in the non‐glacierized humid regions exhibits an equilibrium. Contrastively, TWS declines in drylands are more widespread and enduring with human groundwater depletion. Our analysis highlights a pressing need for improving water conservation strategies in global drylands. Key Points: Recent zonal terrestrial water storage (TWS) losses are primary results of climate change and human activities, instead of climate variabilityIn humid regions, glacier loss fully explains the net TWS decline, meaning a water budget equilibrium in non‐glacierized humid regionsIn drylands, widespread TWS losses are mainly attributed to direct human activities [ABSTRACT FROM AUTHOR]

The present study explores the impact of climate change on subsistence farming in Mutoko community, Zimbabwe. Mutoko is a rural community situated in the eastern part of Zimbabwe. Climate change is one of the biggest environmental challenges. Its impact is more intense in developing countries, particularly in rural communities which have become a major concern to the societal livelihood. The most affected people are the rural poor because they are highly dependent on climatic and environmental factors in addition to their greater reliance on climate-sensitive sectors such as agriculture and health, posing critical challenges for natural development. Focus group discussions were conducted to explore perceptions of climate change and its impacts on subsistence farming. The study reports community members' awareness of changes in the local natural environment. The changes are increased temperature and scarcity of rain. Observable impacts of these changes are decreased crop yields because of drought. The findings are supported by observation that Zimbabwe lies in a semi-arid region with limited and unreliable rainfall patterns and temperature variations. Rainfall exhibits considerable spatial and temporal variability. It is concluded that the impact of climate change on subsistence farming is real and is negatively affecting food security in the study area. [ABSTRACT FROM AUTHOR]

Water managers across the United States face the need to make informed policy decisions regarding long-term impacts of climate change on water resources. To provide a scientifically informed basis for this, the evolution of important components of the basin-scale water balance through the end of the twenty-first century is estimated. Bias-corrected and spatially downscaled climate projections, from phase 3 of the Coupled Model Intercomparison Project (CMIP3) of the World Climate Research Programme, were used to drive a spatially distributed Variable Infiltration Capacity (VIC) model of hydrologic processes in the Salt-Verde basin in the southwestern United States. From the suite of CMIP3 models, the authors select a five-model subset, including three that best reproduce the historical climatology for the study region, plus two others to represent wetter and drier than model average conditions, so as to represent the range of GCM prediction uncertainty. For each GCM, data for three emission scenarios (A1B, A2, and B1) were used to drive the hydrologic model into the future. The projections of this model ensemble indicate a statistically significant 25% decrease in streamflow by the end of the twenty-first century. The primary cause for this change is due to projected decreases in winter precipitation accompanied by significant (temperature driven) reductions in storage of snow and increased winter evaporation. The results show that water management in central Arizona is highly likely to be impacted by changes in regional climate. [ABSTRACT FROM AUTHOR]

An atmospheric general circulation model (AGCM) is coupled to three different land surface schemes (LSSs), both individually and in combination (i.e., the LSSs receive the same AGCM forcing each time step and the averaged upward surface fluxes are passed back to the AGCM), to study the uncertainty of simulated climatologies and variabilities caused by different LSSs. This tiling of the LSSs is done to study the uncertainty of simulated mean climate and climate variability caused by variations between LSSs. The three LSSs produce significantly different surface fluxes over most of the land, no matter whether they are coupled individually or in combination. Although the three LSSs receive the same atmospheric forcing in the combined experiment, the inter-LSS spread of latent heat flux can be larger or smaller than the individually coupled experiment, depending mostly on the evaporation regime of the schemes in different regions. Differences in precipitation are the main reason for the different latent heat fluxes over semiarid regions, but for sensible heat flux, the atmospheric differences and LSS differences have comparable contributions. The influence of LSS uncertainties on the simulation of surface temperature is strongest in dry seasons, and its influence on daily maximum temperature is stronger than on minimum temperature. Land–atmosphere interaction can dampen the impact of LSS uncertainties on surface temperature in the tropics, but can strengthen their impact in middle to high latitudes. Variations in the persistence of surface heat fluxes exist among the LSSs, which, however, have little impact on the global pattern of precipitation persistence. The results provide guidance to future diagnosis of model uncertainties related to LSSs. [ABSTRACT FROM AUTHOR]