Assessing the impacts of climatic change on mountain water resources

Climate change impacts on groundwater discharge-dependent streamflow in an alpine headwater catchment

Climate change will have-and, in much of the world, is already having-a pronounced impact on alpine water resources. A deeper understanding of the future role of groundwater in alpine catchments, including quantification of climate change impacts on groundwater discharge, is vital for understanding the future of alpine water resources as a whole. Here, we develop and couple a geophysics-informed groundwater model with a net recharge model to investigate the impacts of climate change on a nival-regime alpine headwater catchment with significant unconfined Quaternary aquifer coverage. Flow in the groundwater-fed stream at the catchment outlet is analysed to determine changes in its annual dynamics. Comparing the periods 2020-2040 and 2080-2100 under ten RCP-8.5 climate models, we find a 35 % decrease in mean groundwater discharge and an increase in no-flow periods from ~0 % to 4.3 %. We also observe significant changes to the timing of monthly mean discharge maxima and minima, which shift ~1 month and ~5 months earlier, respectively. While groundwater has the potential to dampen the impacts of snow cover loss, currently perennial nival-regime alpine streams could be at risk of becoming intermittent by the end of the century. Our study underscores the increasingly critical role that groundwater will play in alpine catchments and emphasizes the need for quantitative understanding of the limits to its buffering capacity.

Towards a greater engagement of universities in addressing climate change challenges

Many higher education institutions around the world are engaged in efforts to tackle climate change. This takes place by not only reducing their own carbon footprint but also by educating future leaders and contributing valuable research and expertise to the global effort to combat climate change. However, there is a need for studies that identify the nature of their engagement on the topic, and the extent to which they are contributing towards addressing the many problems associated with climate change. Against this background, this paper describes a study that consisted of a review of the literature and the use of case studies, which outline the importance of university engagement in climate change and describe its main features. The study identified the fact that even though climate change is a matter of great relevance to universities, its coverage in university programmes is not as wide as one could expect. Based on the findings, the paper also lists the challenges associated with the inclusion of climate change in university programmes. Finally, it describes some of the measures which may be deployed in order to maximise the contribution of higher education towards handling the challenges associated with a changing climate.

Conflict-Sensitive Climate Change Adaptation: A Review

Climate change adaptation (CCA) evolved in the global policy framework in the early 1990s. However, it began to flourish about a decade later through a subsequent development of institutions, policies and supporting financial mechanisms. Various adaptation approaches and development practices have been evolving over the last couple of decades through a process of scrutiny, debates, and critiques. One such recent approach is called conflict-sensitive adaptation, which encompasses concepts to understand potential conflict-inflicting elements and peacebuilding aspects of adaptation interventions. This paper examines 35 peer-reviewed research articles that have analysed field data with the notion of conceptualising conflict-sensitive CCA initiatives. Emerging key results were presented and discussed in different academic forums to stimulate peer reflections and debates. We found that the understanding of conflict-sensitive adaptation has its universality in engaging with diverse stakeholders. However, practicalities were different in the cases of the global north and the global south. In the global south, there is a concentration of research in areas of pre-existing conflict in Africa and Asia, where climate change links are often assumed from IPCC reports in order to compensate for the unavailability of field data. However, from the perspective of adaptation politics and governance, there is a concerted urge for the emancipatory participation of local and marginalised populations. We argue for a need to pretest adaptation projects through a conflict lens. Decolonising the adaptation and understanding of local geography is critical in such planning.

The Spatiotemporal Change of Glacier Runoff Is Comparably Attributed to Climatic Factors and Physical Properties in Northwestern China

The spatiotemporal regimes of glacier runoff (GR) under a warming climate are of great concern, especially in dryland areas in northwestern China (DAC). Due to the difficulty of observing GR, little attention has been given to the spatiotemporal change in GR at regional scales. This study uses the regional individual glacier mass balance (GMB) dataset developed by digital elevation models (DEMs) to simulate the spatiotemporal regime of GR using atmospheric parameters considering both ablation and accumulation processes on glaciers. In this study, GR, including glacier meltwater runoff (MR) and delayed water runoff (DR) of the DAC, was quantitatively assessed at a catchment scale from 1961 to 2015. The total annual GR in the DAC was (100.81 ± 68.71) × 108 m3 in 1961–2015, where MR accounted for 68%. Most basins had continuously increasing tendencies of different magnitudes from 1961 to 2015. The least absolute shrinkage and selection operator (LASSO) and random forest techniques were used to explore the contributions of climate factors and glacier physical properties to GR, and the results indicated that climate factors could explain 56.64% of the variation. In comparison, the remaining 43.36% could be explained by the physical properties of glaciers themselves (i.e., degree-day factor on ice, degree-day factor on snow, glacier median height, aspect, and slope). This study not only improves our understanding of the spatiotemporal change in GR in the drylands of northwestern China at spatial and temporal resolutions but also highlights the role of physical properties in explaining the heterogeneous dynamics among GRs unlike previous studies that only emphasize rising temperatures.

Impact of Hydrological Infrastructure Projects on Land Use/Cover and Socioeconomic Development in Arid Regions—Evidence from the Upper Atbara and Setit Dam Complex, Kassala, Eastern Sudan

In recent years, Africa has seen much construction of large-scale hydrological infrastructures in the arid and semi-arid regions of numerous countries. This paper aims to quantify the effects of this form of hydrological infrastructure, especially the Upper Atbara and Setit Dam Complex (UASDC) in Eastern Sudan, on the land use/cover (LUC) and socioeconomic domains. This paper attempts to advance our understanding of this phenomenon by using multiple approaches. A framework using the integration of 3S technologies and a logical approach for quantifying the significance of the results to society has been developed. The method used Landsat5 TM in 2002, Sentinel2A in 2018, and statistical data to create the LUC map. The final map included seven classes; the overall accuracy of changes in LUC patterns was 94.9% in 2002 and 93% in the results reveal that significant changes occurred in terms of LUC, having a considerable effect on socio-economic development. The results were analyzed with the logical approach for overall objectives, where 85% represents S1, 3.3% represents S2, and 11.7% represents S3, respectively. This study provides an insight into further investigations of the dam’s effect on climate and groundwater, and offers a new perspective on land use prediction, simulation, and environmental sustainability.

Isotopic content in high mountain karst aquifers as a proxy for climate change impact in Mediterranean zones: The Port del Comte karst aquifer (SE Pyrenees, Catalonia, Spain)

The objective of this work is to characterize the impact of climate change in the karst aquifer of the Port del Comte Massif (PCM). Six regional climate models (RCMs) from CLYM'PY Project are used to analyse the magnitude and trends of changes on precipitation and temperature (RCP4.5 and RCP8.5 scenarios) and how these changes propagate through the hydrogeological system as groundwater resources availability and the associated water isotopic content. The study uses the RCMs climate change forcings as input data to a combination of (1) a semi-distributed hydrological model for simulating the hydrodynamical response of the aquifer, and (2) a lumped parameter model for simulating the isotopic content in groundwater at the outlet of the aquifer. A mean decrease of 2.6% and 1.9% in yearly precipitation and a mean increase of 1.9 and 3.1 °C in average temperature is expected in PCM at the end of the 21st century in the RCP4.5 and RCP8.5 scenarios, respectively. This climate signal entering the hydrogeological system results in a mean decrease in recharge of 3.9% and 0.5% from rainfall and of 59.3% and 76.1% from snowmelt, and a decrease of 7.6% and 4.5% in total system discharge, but also generates an isotopic enrichment in groundwater discharge (δ¹⁸O_GW) of 0.50‰ and 0.84‰, respectively. Moreover, from a long-term (2010-2100) perspective, the mean trend in δ¹⁸O_GW is 0.7‰/100 yr and 1.2‰/100 yr for RCP4.5 and RCP8.5, respectively, resulting in easily measurable annual lapse rates with the current analytical methods.

Assessment of trends in climatic extremes from observational data in the Kashmir basin, NW Himalaya

The present study aims to assess the recent changes and trends in the extreme climate indices in the Kashmir basin using the observational records from 1980 to 2016. The extreme climate indices were computed using the ClimPACT2 software and a total of 39 indices were selected for the analysis having particular utility to various sectors like agriculture, water resources, energy consumption, and human health. Besides adopting the station scale analysis, regional averages were computed for each index. In terms of the mean climatology, an increase has been observed in the annual mean temperature with a magnitude of 0.024 °C/year. Further, differential warming patterns have been observed in the mean maximum and minimum temperatures with mean maximum temperature revealing higher increases than mean minimum temperature. On the other hand, the annual precipitation shows a decrease over most of the region, and the decreases are more pronouncing in the higher altitudes. The trend analysis of the extreme indices reveals that in consonance with the rising temperature there has been an increase in the warm temperatures and decrease in the cold temperatures across the Kashmir basin. Furthermore, our analysis suggests a decrease in the extreme precipitation events. The drought indices viz., Standardised Precipitation Index (SPI), and Standardised Precipitation Evapotranspiration Index (SPEI) manifest decreasing trends with the tendency towards drier regimes implying the need for better water resource management in the region under changing climate.

Risk perception of climate change and natural hazards in global mountain regions: A critical review

Mountains are highly sensitive to climate change. Their elevated areas provide essential ecosystem services both for the surrounding mountainous regions and particularly for adjacent lowlands. Impacts of a warmer climate affect these services and have negative consequences on the supply of water, on biodiversity and on protection from natural hazards. Mountain social-ecological systems are affected by these changes, which also influence communities' risk perception and responses to changing climate conditions. Therefore, to understand individual and societal responses to climate change in mountain areas, aspects and drivers of risk perception need to be scrutinised. This article presents the findings of a literature review of recent English language publications on risk perception in connection to climate change and related natural hazards in mountain regions worldwide. Studies were selected from recorded entries in JSTOR, Science Direct, Scopus and Web of Science covering the period 2000-2019 and analysed in two steps (structured exploratory analysis, n = 249 and in-depth analysis, n = 72) with respect to the studies' research question, methodology, geographical scope and risk perception drivers. The review reveals that socio-demographic factors, like gender, age and personal experiences, have a crucial impact on individual risk perception. Some of the less tangible but nevertheless decisive factors are important in mountain regions such as place attachment and socio-cultural practices. In conclusion, there is however little information in the literature which addresses the specific situation of risk perception in mountain areas and its influence on communities' responses to environmental changes. Further, we observed a strong gap concerning the integration of indigenous knowledge in risk perception research. Many studies overlook or oversimplify local knowledge and the cultural dimensions of risk perception. Based on these results, the paper identifies several gaps in research and knowledge which may influence the design of climate risk management strategies as well as on their successful implementation.

Geography Matters, But… Evolving Success Factors for Nature-Oriented Health Tourism within Selected Alpine Destinations

This paper analyzes the success factors of health tourism based on natural attractions in selected European spa and health destinations. The natural resources included in the offers, such as water, salt, and air, play a central role in this context, as their evidence-based effects have a high relevance for the health and wellbeing of tourists. Due to its specific geographical location and considering the threat of climate change, however, this offer is facing increasing challenges which make adaptation strategies necessary. In addition to a conceptional introduction to the topic, this paper contains a descriptive analysis of tourism statistics and the results from self-administered questionnaires with six selected representatives from alpine health destinations (DE, FR, IT, AT, CH, SI). The results show varying forms of health tourism based on natural attractions, which are also reflected in online marketing, with potential for optimization. The web research and the responses to the questionnaire revealed that evidence-based studies hardly play a role in promoting health touristic offers. Furthermore, climate change effects on natural attractions are considered extremely small and tend to prompt the development of new offers. Health destinations are advised to generate a clearer focus on the risks of climate change regarding natural resources.

Future Hydrology of the Cryospheric Driven Lake Como Catchment in Italy under Climate Change Scenarios

We present an assessment of climate change impact on the hydrology of the Lago di Como lake catchment of Italy. On one side, the lake provides water for irrigation of the Po valley during summer, and on the other side its regulation is crucial to prevent flood risk, especially in fall and winter. The dynamics of lake Como are linked to the complex cryospheric hydrology of its Alpine contributing catchment, which is in turn expected to change radically under prospective global warming. The Poli-Hydro model is used here to simulate the cryospheric processes affecting the hydrology of this high-altitude catchment. We demonstrated the model’s accuracy against historical hydrological observations, available during 2002–2018. We then used four Representative Concentration Pathways scenarios, provided by three Global Circulation Models under the AR6 of IPCC, to project potential climate change until 2100. We thereby derived daily series of rainfall and temperature, to be used as inputs for hydrological simulations. The climate projections here highlight a substantial increase in temperature at the end of the century, between +0.61° and +5.96°, which would lead to a decrease in the total ice volume in the catchment, by −50% to −77%. Moreover, there would be a decrease in the contribution of snow melt to the annual lake inflow, and an increase in ice melt under the worst-case scenarios. Overall, the annual Lake inflows would increase during autumn and winter and would decrease in summer. Our study may provide a tool to help policy makers to henceforth evaluate adaptation strategies in the area.

Comparing Approaches for Reconstructing Groundwater Levels in the Mountainous Regions of Interior British Columbia, Canada, Using Tree Ring Widths

Observed groundwater level records are relatively short (<100 years), limiting long-term studies of groundwater variability that could provide valuable insight into climate change effects. This study uses tree ring data from the International Tree Ring Database (ITRDB) and groundwater level data from 22 provincial observation wells to evaluate different approaches for reconstructing groundwater levels from tree ring widths in the mountainous southern interior of British Columbia, Canada. The twenty-eight reconstruction models consider the selection of observation wells (e.g., regional average groundwater level vs. wells classified by recharge mechanism) and the search area for potential tree ring records (climate footprint vs. North American Ecoregions). Results show that if the climate footprint is used, reconstructions are statistically valid if the wells are grouped according to recharge mechanism, with streamflow-driven and high-elevation recharge-driven wells (both snowmelt-dominated) producing valid models. Of all the ecoregions considered, only the Coast Mountain Ecoregion models are statistically valid for both the regional average groundwater level and high-elevation recharge-driven systems. No model is statistically valid for low-elevation recharge-driven systems (rainfall-dominated). The longest models extend the groundwater level record to the year 1500, with the highest confidence in the later portions of the reconstructions going back to the year 1800.

Essential Variables for Environmental Monitoring: What Are the Possible Contributions of Earth Observation Data Cubes?

Environmental sustainability is nowadays a major global issue that requires efficient and effective responses from governments. Essential variables (EV) have emerged in different scientific communities as a means to characterize and follow environmental changes through a set of measurements required to support policy evidence. To help track these changes, our planet has been under continuous observation from satellites since 1972. Currently, petabytes of satellite Earth observation (EO) data are freely available. However, the full information potential of EO data has not been yet realized because many big data challenges and complexity barriers hinder their effective use. Consequently, facilitating the production of EVs using the wealth of satellite EO data can be beneficial for environmental monitoring systems. In response to this issue, a comprehensive list of EVs that can take advantage of consistent time-series satellite data has been derived. In addition, a set of use-cases, using an Earth Observation Data Cube (EODC) to process large volumes of satellite data, have been implemented to demonstrate the practical applicability of EODC to produce EVs. The proposed approach has been successfully tested showing that EODC can facilitate the production of EVs at different scales and benefiting from the spatial and temporal dimension of satellite EO data for enhanced environmental monitoring.

Impact of climate change on hydrology components using CORDEX South Asia climate model in Wunna, Bharathpuzha, and Mahanadi, India

Detecting the probable impact of climate change responses on hydrological components is most important for understanding such changes on water resources. The impact of climate change on virtual parameters of water was assessed through hydrological modeling of the Wunna, Mahanadi (Middle), and Bharathpuzha watersheds. In this article, future hydrological component responses under two Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios were considered for investigating the runoff, sediment, and water storage components. RegCM4 CSIRO-Mk3.6.0 CORDEX South Asia of RCM model was used which is specially downscaled for the Asian region by IITM-India. Delta change method was adopted to remove bias correction in RCM data. Hydrological simulation for current and future periods was performed by GIS interfaced Soil Water and Assessment Tool (SWAT) model. The surface runoff of Wunna and Bharathpuzha watersheds and the yield of sediment are expected to increase further under RCP8.5 than RCP4.5 and in contrast to Mahanadi watershed. Both blue water storage (BW) and green water storage (GWS) of Wunna watershed are expected to decline under RCP4.5, and rise under RCP8.5 scenario. Both BW and GWS of Bharathpuzha are expected to increase in the future except in western region under RCP4.5 scenario. BW of Mahanadi is expected to increase in the future. However, GWS will decrease in some of the sub-basins. The model-generated results will be helpful for future water resources planning and development.

A Forty-Year Karstic Critical Zone Survey (Baget Catchment, Pyrenees-France): Lithologic and Hydroclimatic Controls on Seasonal and Inter-Annual Variations of Stream Water Chemical Composition, pCO2, and Carbonate Equilibrium

The long-term trends and seasonal patterns of stream water chemical composition in a small remote forested karst catchment, were investigated from 1978 to 2018. Calcium, magnesium, and bicarbonates, the dominant ions, increased over the period together with temperature, while sulfates decreased. Carbonate and sulfate mineral dissolution was the main source of these elements. These trends and the seasonal opposite patterns of discharge vs. temperature, calcite saturation index vs. pCO2 and bicarbonate vs. sulfates, suggested the influence of discharge, of reduced long-range atmospheric pollution, and of increasing air temperature on biological activity and carbonate dissolution. Furthermore, the hydrological regime controlled the seasonal stream water chemical composition and fluxes by: (i) a dilution during the high discharge period, (ii) a change in the contribution rate of the waters draining different lithological areas in the catchment, e.g., the increased sulfates to bicarbonates ratio during summer low flows, with a maximum alkalinity decrease of 24%, and (iii) a “piston” and a “flushing” effects of dissolved elements stored in soils and epikarst with the first autumn heavy rains. Long-term stream water hydrochemical surveys of karst system have proved to be powerful indicators of biogeochemical processes, water sources and pathways under variable natural and anthropogenic environmental pressure conditions.

Changes in climate patterns and their association to natural hazard distribution in South Tyrol (Eastern Italian Alps)

In Alpine regions changes in seasonal climatic parameters, such as temperature, rainfall, and snow amount have already been observed. Specifically, in the South Tyrol area, meteorological observations indicate that temperatures are increasing and the number of snow days has generally diminished over time with perennial snow line now observed at higher elevations. Changes in rainfall have also been observed with more events associated with higher temperatures in the summer season. Natural hazards - mainly debris and mud flows, landslides, avalanches, rock falls, and (flash) floods - that affect this area every year, damaging population and infrastructures, are either weather or cryosphere-related. While these events have been recorded sporadically since the beginning of the 20th century, a systematic approach of their inventory has been done by local authorities since the 1990s. So far, Earth observation data has not been exploited to complete or complement existing inventories nor have they been used to investigate the influence of climate perturbation on potentially dangerous natural phenomena. The research presented here thus has three objectives: (i) analyse long time series of climate data and hazard occurrence in South Tyrol to examine if these records exhibit a coherent response of hazards to changes in climate; (ii) measure the spatio-temporal evolution of climatic and natural hazard events recorded, and (iii) explore potential relations between meteorological conditions and the hazard occurrence. In this context, in-situ and satellite-based climate data are exploited to study natural hazard triggers while the potential of Earth observation data is evaluated as a complement to the existing historical records of natural hazards. Specifically, Copernicus Sentinel-1 images are used to detect the spatio-temporal distribution of slow earth surface deformations and the results used for checking the completeness of the actual slow-moving landslide inventories. Hazard-related changes in the South Tyrolian landscape have also been analysed in relation to particular meteorological events at a regional scale, assessing trends and anomalies. Results show that: (i) satellite data are very useful to complement the existing natural hazard inventories; (ii) in-situ and satellite-based climate records show similar patterns but differ due to regional versus local variability; (iii) even in a data-rich region such as the analysed area, the overall response of natural hazard occurrence, magnitude, and frequency to change in climate variables is difficult to decipher due to the presence of multiple triggers and locally driven ground responses. However, an increase in the average annual duration of rainfall events and debris flow occurrence can be observed.

National Open Data Cubes and Their Contribution to Country-Level Development Policies and Practices

The emerging global trend of satellite operators producing analysis-ready data combined with open source tools for managing and exploiting these data are leading to more and more countries using Earth observation data to drive progress against key national and international development agendas. This paper provides examples from Australia, Mexico, Switzerland, and Tanzania on how the Open Data Cube technology has been combined with analysis-ready data to provide new insights and support better policy making across issues as diverse as water resource management through to urbanization and environmental–economic accounting.

Winter precipitation - not summer temperature - is still the main driver for Alpine shrub growth

High latitude and altitude environments are universally recognized as particularly sensitive to environmental changes and the current climate warming is inducing remarkable transformations on vegetation assemblage in these temperature-limited regions. However, next to the wealth of studies describing the effect of rising growing season temperature on trees, much less is known about the concurrent effects of precipitation and snowpack dynamics on the other key component of alpine vegetation represented by prostrate life forms. Selecting the most widespread shrub species in the North Hemisphere, we assembled a monospecific (Juniperus communis L.) network of 7 sites overarching the European Alps, measured the annual growth on >330 individuals and assessed the climate-growth associations for the last century (1910-2010) adopting a new model estimating the solid fraction of precipitation from unique highly-resolved daily climate records. Despite the high space-time variability of the yearly precipitation amount and distribution across the region, our analysis found a prominent, consistent and negative role of winter precipitation for shrub growth. Moreover, this crucial role of snow is maintained even in recent years, despite the persistent and significant warming trend. The presence of this underrated key factor for Alpine long-lived vegetation will require a thorough consideration. For the prostrate life form, not only temperature but also the solid fraction of winter precipitation should be considered to improve the projections of future growth trajectories.

Current Practice and Recommendations for Modelling Global Change Impacts on Water Resource in the Himalayas

Global change is expected to have a strong impact in the Himalayan region. The climatic and orographic conditions result in unique modelling challenges and requirements. This paper critically appraises recent hydrological modelling applications in Himalayan river basins, focusing on their utility to analyse the impacts of future climate and socio-economic changes on water resource availability in the region. Results show that the latter are only represented by land use change. Distributed, process-based hydrological models coupled with temperature-index melt models are predominant. The choice of spatial discretisation is critical for model performance due to the strong influence of elevation on meteorological variables and snow/ice accumulation and melt. However, the sparsity and limited reliability of point weather data, and the biases and low resolution of gridded datasets, hinder the representation of the meteorological complexity. These data limitations often limit the selection of models and the quality of the outputs by forcing the exclusion of processes that are significant to the local hydrology. The absence of observations for water stores and fluxes other than river flows prevents multi-variable calibration and increases the risk of equifinality. The uncertainties arising from these limitations are amplified in climate change analyses and, thus, systematic assessment of uncertainty propagation is required. Based on these insights, transferable recommendations are made on directions for future data collection and model applications that may enhance realism within models and advance the ability of global change impact assessments to inform adaptation planning in this globally important region.

Multi-risk assessment in mountain regions: A review of modelling approaches for climate change adaptation

Climate change has already led to a wide range of impacts on our society, the economy and the environment. According to future scenarios, mountain regions are highly vulnerable to climate impacts, including changes in the water cycle (e.g. rainfall extremes, melting of glaciers, river runoff), loss of biodiversity and ecosystems services, damages to local economy (drinking water supply, hydropower generation, agricultural suitability) and human safety (risks of natural hazards). This is due to their exposure to recent climate warming (e.g. temperature regime changes, thawing of permafrost) and the high degree of specialization of both natural and human systems (e.g. mountain species, valley population density, tourism-based economy). These characteristics call for the application of risk assessment methodologies able to describe the complex interactions among multiple hazards, biophysical and socio-economic systems, towards climate change adaptation. Current approaches used to assess climate change risks often address individual risks separately and do not fulfil a comprehensive representation of cumulative effects associated to different hazards (i.e. compound events). Moreover, pioneering multi-layer single risk assessment (i.e. overlapping of single-risk assessments addressing different hazards) is still widely used, causing misleading evaluations of multi-risk processes. This raises key questions about the distinctive features of multi-risk assessments and the available tools and methods to address them. Here we present a review of five cutting-edge modelling approaches (Bayesian networks, agent-based models, system dynamic models, event and fault trees, and hybrid models), exploring their potential applications for multi-risk assessment and climate change adaptation in mountain regions. The comparative analysis sheds light on advantages and limitations of each approach, providing a roadmap for methodological and technical implementation of multi-risk assessment according to distinguished criteria (e.g. spatial and temporal dynamics, uncertainty management, cross-sectoral assessment, adaptation measures integration, data required and level of complexity). The results show limited applications of the selected methodologies in addressing the climate and risks challenge in mountain environments. In particular, system dynamic and hybrid models demonstrate higher potential for further applications to represent climate change effects on multi-risk processes for an effective implementation of climate adaptation strategies.

Glacial influence and stream macroinvertebrate biodiversity under climate change: Lessons from the Southern Alps

The aim of this work was to highlight the main ecological predictors driving invertebrate distribution in eight glacier-fed streams in the Southern Alps. Thirty-five sites belonging to four stream types were sampled monthly during the ablation season of one, two or three years between 1996 and 2014. Taxa from glacial (kryal and glacio-rhithral) and non-glacial (kreno-rhithral and lake outlet) sites were separated by canonical correspondence analysis (CCA) along a glacial influence gradient and a hydrological-altitudinal gradient. High glacial influence was associated mainly with low maximum water temperature (Tmax), high Glacial Index (calculated as a function of glacier area and distance from the glacier), and the abundance of Diamesa species (D. steinboecki, D. goetghebueri, D. zernyi, and D. latitarsis). Change-point analysis and Threshold Indicator Taxa Analysis confirmed the CCA results in identifying these Diamesa species as the taxa with the strongest preference for high percent glacier cover in the catchment (change point~30%) and low Tmax (change point~6°C). Temporal changes in community structure were highlighted in seven sites fed by glaciers under different retreat rates. Where the rate was faster and the remaining glacier smaller (≪1km²), the most cold-stenothermal kryal inhabitant, D. steinboecki, almost disappeared or survived only as brachypterous populations, whereas other Diamesinae (Pseudokiefferiella parva), Orthocladiinae (e.g. Eukiefferiella, Orthocladius), Limoniidae, Baetidae, Nemouridae, and non-insect taxa (e.g. Oligochaeta, Hydracarina) became more abundant. Upstream migration was observed in Diamesa spp. which conquered new stream reaches left free by the retreating glacier, and euriecious taxa which colonized reaches with ameliorated environmental conditions, no longer the exclusive habitat of Diamesa spp. Co-occurrence of stochastic and deterministic assembly processes seem to drive spatio-temporal changes in these invertebrate communities. Long-term ecological studies on the adaptive biology of kryal species will be useful to predict the fate of Alpine biodiversity.

Quantifying postglacial sediment storage and denudation rates in a small alpine catchment of the Făgăraș Mountains (Romania)

The study of sediment production, transport, storage and discharge in alpine drainage basins is an essential prerequisite for a better understanding of the postglacial evolution of the alpine landscape. To get an overview on sediment production and alpine landscape evolution in Romania, the current study presents the first alpine sediment storage quantification in the Romanian Carpathians. Postglacial denudation was quantified within the small alpine catchment of the Doamnei Valley (3.62km²), located in the central part of the Făgăraș Mountains. The quantification of sediment volumes was performed through a combined approach consisting of: (i) detailed geomorphological mapping of sediment storage landforms, by means of high accuracy field and remote mapping of sediment storage landforms, (ii) shallow geophysical investigations and (iii) geographic information systems modeling techniques. A total of 64 ground penetrating radar profiles were conducted through the valley for sediment thickness determination of individual landforms. Through parallel profiling, 5 electrical resistivity tomography profiles were also performed for the comparison of bedrock depths in order to determine the overall degree of accuracy of the geophysical investigations applied. In total, 79 sediment storage landforms were identified. Talus sheets were found to be the most dominant landforms within the investigated area, followed by talus cones, moraines and fluvio-torrential deposits. Sediment volume for the Doamnei Valley was calculated to be 7.08±1.42 10⁶m³, corresponding to a mean sediment thickness of 4.20m, with the hanging cirques and valleys subsystem storing 48.58% of the total sediment volume, despite covering just 22% of the investigated area. Sediment volume was used in the determination of mean annual denudation rates for the entire catchment (0.20mm/y±0.04mm/y) as well as for mean annual mass transfer (406.2±31.6t/km²/y), based on a time span of 13ka.

Climate change, water supply and environmental problems of headwaters: The paradigmatic case of the Tiber, Savio and Marecchia rivers (Central Italy)

River headwaters, in spite of their importance for habitats and water supply, are often inadequately studied and managed. This study discusses the effects of the hydrogeological system and climatic variations on the environment of Monte Fumaiolo (Central Italy), which corresponds to the headwaters of the rivers Tiber, Savio and Marecchia. The area is a key system for supplying drinking-water and is also the habitat of amphibians such as the endemic and endangered Bombina pachypus and other amphibian species. Ongoing climate change is affecting the area: during the last 30years, five prolonged droughts have occurred, against only one in the preceding 40years. On all time-scales, there is a decrease in rainfall during the recharge period and an increase of temperature: these trends correspond to a decrease in water yield of about 12% over the last 30years. The hydrologic system of the study area is composed of one basic aquifer and a few perched aquifers feeding springs. Their resilience to drought depends on their geological setting: study of some depletion curves helped us to understand the geological setting of the various types, and two promising sites for the habitat preservation of amphibians were identified. Study results indicate new approaches to the study and management of the environment and its water supply, which could be useful in similar areas.

Cryospheric Science: research framework and disciplinary system

Cryospheric changes and their impacts have received increasing concern, extending the research to include the interactions between earth spheres and the impacts of and social adaptation to cryospheric changes. As a result, Cryospheric Science is rapidly developing. However, the research framework of Cryospheric Science has not completely been set up, and the intension and extension of Cryospheric Science are unclear. Following a literature review, the research framework for Cryospheric Science and the discipline components are analysed in this paper. We consider that Cryospheric Science is an inevitable product of international research on the earth and environmental changes as well as on human sustainable development. It will not only strengthen the linkage between the cryosphere and other earth spheres by deepening traditional research areas, but will also bring more focus on the critical roles of the cryosphere in interactions between earth spheres, and will enhance the relationship between cryospheric change and climate, ecology, hydrology, surface environment and sustainable development. The disciplinary tree of Cryospheric Science is developed following the mainstream of change-impacts adaptation. The disciplines of Cryospheric Science were teased out against characteristics of traditional branches and the developing interdisciplinary branches of cryosphere elements, which will provide reference to Cryospheric Science as it systematically grows to maturity.

Integrated Taxonomy and DNA Barcoding of Alpine Midges (Diptera: Chironomidae)

Rapid and efficient DNA-based tools are recommended for the evaluation of the insect biodiversity of high-altitude streams. In the present study, focused principally on larvae of the genus Diamesa Meigen 1835 (Diptera: Chironomidae), the congruence between morphological/molecular delimitation of species as well as performances in taxonomic assignments were evaluated. A fragment of the mitochondrial cox1 gene was obtained from 112 larvae, pupae and adults (Diamesinae, Orthocladiinae and Tanypodinae) that were collected in different mountain regions of the Alps and Apennines. On the basis of morphological characters 102 specimens were attributed to 16 species, and the remaining ten specimens were identified to the genus level. Molecular species delimitation was performed using: i) distance-based Automatic Barcode Gap Discovery (ABGD), with no a priori assumptions on species identification; and ii) coalescent tree-based approaches as the Generalized Mixed Yule Coalescent model, its Bayesian implementation and Bayesian Poisson Tree Processes. The ABGD analysis, estimating an optimal intra/interspecific nucleotide distance threshold of 0.7%-1.4%, identified 23 putative species; the tree-based approaches, identified between 25-26 entities, provided nearly identical results. All species belonging to zernyi, steinboecki, latitarsis, bertrami, dampfi and incallida groups, as well as outgroup species, are recovered as separate entities, perfectly matching the identified morphospecies. In contrast, within the cinerella group, cases of discrepancy arose: i) the two morphologically separate species D. cinerella and D. tonsa are neither monophyletic nor diagnosable exhibiting low values of between-taxa nucleotide mean divergence (0.94%); ii) few cases of larvae morphological misidentification were observed. Head capsule color is confirmed to be a valid character able to discriminate larvae of D. zernyi, D. tonsa and D. cinerella, but it is here better defined as a color gradient between the setae submenti and genal setae. DNA barcodes performances were high: average accuracy was ~89% and precision of ~99%. On the basis of the present data, we can thus conclude that molecular identification represents a promising tool that could be effectively adopted in evaluating biodiversity of high-altitude streams.

Impact of climate change and water use policies on hydropower potential in the south-eastern Alpine region

Climate change is expected to cause alterations of streamflow regimes in the Alpine region, with possible relevant consequences for several socio-economic sectors including hydropower production. The impact of climate change on water resources and hydropower production is evaluated with reference to the Noce catchment, which is located in the Southeastern Alps, Italy. Projected changes of precipitation and temperature, derived from an ensemble of 4 climate model (CM) runs for the period 2040-2070 under the SRES A1B emission scenario, have been downscaled and bias corrected before using them as climatic forcing in a hydrological model. Projections indicate an increase of the mean temperature of the catchment in the range 2-4K, depending on the climate model used. Projections of precipitation indicate an increase of annual precipitation in the range between 2% and 6% with larger changes in winter and autumn. Hydrological simulations show an increase of water yield during the period 2040-2070 with respect to 1970-2000. Furthermore, a transition from glacio-nival to nival regime is projected for the catchment. Hydrological regime is expected to change as a consequence of less winter precipitation falling as snow and anticipated melting in spring, with the runoff peak decreasing in intensity and anticipating from July to June. Changes in water availability reflect in the Technical Hydropower Potential (THP) of the catchment, with larger changes projected for the hydropower plants located at the highest altitudes. Finally, the impacts on THP of water use policies such as the introduction of prescriptions for minimum ecological flow (MEF) have been analyzed. Simulations indicate that in the lower part of the catchment reduction of the hydropower production due to MEF releases from the storage reservoirs counterbalances the benefits associated to the projected increases of inflows as foreseen by simulations driven only by climate change.

Potential impacts of climate change on flow regime and fish habitat in mountain rivers of the south-western Balkans

The climate change in the Mediterranean area is expected to have significant impacts on the aquatic ecosystems and particular in the mountain rivers and streams that often host important species such as the Salmo farioides, Karaman 1938. These impacts will most possibly affect the habitat availability for various aquatic species resulting to an essential alteration of the water requirements, either for dams or other water abstractions, in order to maintain the essential levels of ecological flow for the rivers. The main scope of this study was to assess potential climate change impacts on the hydrological patterns and typical biota for a south-western Balkan mountain river, the Acheloos. The altered flow regimes under different emission scenarios of the Intergovernmental Panel on Climate Change (IPCC) were estimated using a hydrological model and based on regional climate simulations over the study area. The Indicators of Hydrologic Alteration (IHA) methodology was then used to assess the potential streamflow alterations in the studied river due to predicted climate change conditions. A fish habitat simulation method integrating univariate habitat suitability curves and hydraulic modeling techniques were used to assess the impacts on the relationships between the aquatic biota and hydrological status utilizing a sentinel species, the West Balkan trout. The most prominent effects of the climate change scenarios depict severe flow reductions that are likely to occur especially during the summer flows, changing the duration and depressing the magnitude of the natural low flow conditions. Weighted Usable Area-flow curves indicated the limitation of suitable habitat for the native trout. Finally, this preliminary application highlighted the potential of science-based hydrological and habitat simulation approaches that are relevant to both biological quality elements (fish) and current EU Water policy to serve as efficient tools for the estimation of possible climate change impacts on the south-western Balkan river ecosystems.

A review of hydrological and chemical stressors in the Adige catchment and its ecological status

Quantifying the effects of multiple stressors on Alpine freshwater ecosystems is challenging, due to the lack of tailored field campaigns for the contemporaneous measurement of hydrological, chemical and ecological parameters. Conducting exhaustive field campaigns is costly and hence most of the activities so far have been performed addressing specific environmental issues. An accurate analysis of existing information is therefore useful and necessary, to identify stressors that may act in synergy and to design new field campaigns. We present an extended review of available studies and datasets concerning the hydrological, chemical and ecological status of the Adige, which is the second longest river and the third largest river basin in Italy. The most relevant stressors are discussed in the light of the information extracted from a large number of studies. The detailed analysis of these studies identified that hydrological alterations caused by hydropower production are the main source of stress for the freshwater ecosystems in the Adige catchment. However, concurrent effects with other stressors, such as the release of pollutants from waste water treatment plants or from agricultural and industrial activities, have not been explored at depth, so far. A wealth of available studies address a single stressor separately without exploring their concurrent effect. It is concluded that a combination of extended experimental field campaigns, focusing on the coupled effects of multiple stressors, and modeling activities is highly needed in order to quantify the impact of the multifaceted human pressures on freshwater ecosystems in the Adige river.

Climatic and anthropogenic changes in Western Switzerland: Impacts on water stress

Recent observed hydro-climatic changes in mountainous areas are of concern as they may directly affect capacity to fulfill water needs. The canton of Vaud in Western Switzerland is an example of such a region as it has experienced water shortage episodes during the past decade. Based on an integrated modeling framework, this study explores how hydro-climatic conditions and water needs could evolve in mountain environments and assesses their potential impacts on water stress by the 2060 horizon. Flows were simulated based on a daily semi-distributed hydrological model. Future changes were derived from Swiss climate scenarios based on two regional climate models. Regarding water needs, the authorities of the canton of Vaud provided a population growth scenario while irrigation and livestock trends followed a business-as-usual scenario. Currently, the canton of Vaud experiences moderate water stress from June to August, except in its Alpine area where no stress is noted. In the 2060 horizon, water needs could exceed 80% of the rivers' available resources in low- to mid-altitude environments in mid-summer. This arises from the combination of drier and warmer climate that leads to longer and more severe low flows, and increasing urban (+40%) and irrigation (+25%) water needs. Highlighting regional differences supports the development of sustainable development pathways to reduce water tensions. Based on a quantitative assessment, this study also calls for broader impact studies including water quality issues.

Climate change, human health, and epidemiological transition

The health of populations depends on the availability of clean air, water, food, and sanitation, exposure to pathogens, toxins and environmental hazards, and numerous genetic, behavioral and social factors. For many thousands of years, human life expectancy was low, and population growth was slow. The development of technology-based civilizations facilitated what Abdel Omran called "epidemiological transition," with increasing life expectancy and rapid population growth. To a large extent, the spectacular growth of human populations during the past two centuries was made possible by the energy extracted from fossil fuels. We have now learned, however, that greenhouse gases from fossil fuel combustion are warming the planet's surface, causing changes in oceanic and atmospheric systems, and disrupting weather and hydrological patterns. Climate change poses unprecedented threats to human health by impacts on food and water security, heat waves and droughts, violent storms, infectious disease, and rising sea levels. Whether or not humanity can reduce greenhouse gas emissions quickly enough to slow climate change to a rate that will allow societies to successfully adapt is not yet known. This essay reviews the current state of relevant knowledge, and points in a few directions that those interested in human health may wish to consider.

Shifting mountain snow patterns in a changing climate from remote sensing retrieval

Observed climate change has already led to a wide range of impacts on environmental systems and society. In this context, many mountain regions seem to be particularly sensitive to a changing climate, through increases in temperature coupled with changes in precipitation regimes that are often larger than the global average (EEA, 2012). In mid-latitude mountains, these driving factors strongly influence the variability of the mountain snow-pack, through a decrease in seasonal reserves and earlier melting of the snow pack. These in turn impact on hydrological systems in different watersheds and, ultimately, have consequences for water management. Snow monitoring from remote sensing provides a unique opportunity to address the question of snow cover regime changes at the regional scale. This study outlines the results retrieved from the MODIS satellite images over a time period of 10 hydrological years (2000-2010) and applied to two case studies of the EU FP7 ACQWA project, namely the upper Rhone and Po in Europe and the headwaters of the Syr Darya in Kyrgyzstan (Central Asia). The satellite data were provided by the MODIS Terra MOD-09 reflectance images (NASA) and MOD-10 snow products (NSIDC). Daily snow maps were retrieved over that decade and the results presented here focus on the temporal and spatial changes in snow cover. This paper highlights the statistical bias observed in some specific regions, expressed by the standard deviation values (STD) of annual snow duration. This bias is linked to the response of snow cover to changes in elevation and can be used as a signal of strong instability in regions sensitive to climate change: with alternations of heavy snowfalls and rapid snow melting processes. The interest of the study is to compare the methodology between the medium scales (Europe) and the large scales (Central Asia) in order to overcome the limits of the applied methodologies and to improve their performances. Results show that the yearly snow cover duration increases by 4-5 days per 100 m elevation during the accumulation period, depending of the watershed, while during the melting season the snow depletion rate is 0.3% per day of surface loss for the upper Rhone catchment, 0.4%/day for the Syr Darya headwater basins, and 0.6%/day for the upper Po, respectively. Then, the annual STD maps of snow cover indicate higher values (more than 45 days difference compared to the mean values) for (i) the Po foothill region at medium elevation (SE orientation) and (ii) the Kyrgyzstan high plateaux (permafrost areas). These observations cover only a time-period of 10 years, but exhibit a signal under current climate that is already consistent with the expected decline in snow in these regions in the course of the 21st century.

Changes in glaciers in the Swiss Alps and impact on basin hydrology: current state of the art and future research

Switzerland is one of the countries with some of the longest and best glaciological data sets. Its glaciers and their changes in response to climate have been extensively investigated, and the number and quality of related studies are notable. However, a comprehensive review of glacier changes and their impact on the hydrology of glacierised catchments for Switzerland is missing and we use the opportunity provided by the EU-FP7 ACQWA project to review the current state of knowledge about past changes and future projections. We examine the type of models that have been applied to infer glacier evolution and identify knowledge gaps that should be addressed in future research in addition to those indicated in previous publications. Common characteristics in long-term series of projected future glacier runoff are an initial peak followed by a decline, associated with shifts in seasonality, earlier melt onset and reduced summer runoff. However, the quantitative predictions are difficult to compare, as studies differ in terms of model structure, calibration strategies, input data, temporal and spatial resolution as well as future scenarios used for impact studies. We identify two sources of uncertainties among those emerging from recent research, and use simulations over four glaciers to: i) quantify the importance of the correct extrapolation of air temperature, and ii) point at the key role played by debris cover in modulating glacier response.

Climate change impacts on mass movements--case studies from the European Alps

This paper addresses the current knowledge on climate change impacts on mass movement activity in mountain environments by illustrating characteristic cases of debris flows, rock slope failures and landslides from the French, Italian, and Swiss Alps. It is expected that events are likely to occur less frequently during summer, whereas the anticipated increase of rainfall in spring and fall could likely alter debris-flow activity during the shoulder seasons (March, April, November, and December). The magnitude of debris flows could become larger due to larger amounts of sediment delivered to the channels and as a result of the predicted increase in heavy precipitation events. At the same time, however, debris-flow volumes in high-mountain areas will depend chiefly on the stability and/or movement rates of permafrost bodies, and destabilized rock glaciers could lead to debris flows without historic precedents in the future. The frequency of rock slope failures is likely to increase, as excessively warm air temperatures, glacier shrinkage, as well as permafrost warming and thawing will affect and reduce rock slope stability in the direction that adversely affects rock slope stability. Changes in landslide activity in the French and Western Italian Alps will likely depend on differences in elevation. Above 1500 m asl, the projected decrease in snow season duration in future winters and springs will likely affect the frequency, number and seasonality of landslide reactivations. In Piemonte, for instance, 21st century landslides have been demonstrated to occur more frequently in early spring and to be triggered by moderate rainfalls, but also to occur in smaller numbers. On the contrary, and in line with recent observations, events in autumn, characterized by a large spatial density of landslide occurrences might become more scarce in the Piemonte region.