Search

This Special Issue intended to collect articles focusing on the assessment of the possible effects of climate changes on aquatic species inhabiting inland waters all over the world, including the possible synergistic effects in combination with other anthropogenic stressors. A total of six original articles were published that report on investigations of different freshwater ecosystems across the world, including the mountain streams of the Western United States and Northwest Italy, river basins of Northwest China and Central Italy, a larger lowland river in north Italy, and a high-elevation temporary pond in Central Italy. In most of these papers, special attention was devoted to the repercussions of the climate change and its effects on three important components of the biotic community: the fish, benthic macroinvertebrates, and zooplankton. According to the aims of this Special Issue, three of the articles offer new insight into the synergistic effects of global warming together with other anthropogenic stressors, including water exploitation and alien species invasions. In light of the studies' aim to highlight the effects of climate change, three papers provided analyses of environmental data collected through long-term monitoring. The scientific findings provided by these studies could help to create sound management strategies for freshwater biodiversity conservation. [ABSTRACT FROM AUTHOR]

The Canadian Prairies are associated with high natural hydroclimatic variability including the frequent periodic occurrence of droughts and pluvials. These extremes carry various risks including significant damage to the economy, environment and society. The well-documented level of damage necessitates further risk assessment and planned reductions to vulnerability, particularly in light of a warming climate. A logical starting point involves awareness and information about the changing characteristics of such climate extremes. We focus on the compound occurrence of droughts and pluvials as the risks from this type of event are magnified compared to the hydroclimatic extremes in isolation. Compound droughts and pluvials (CDP) are drought and pluvial events that occur in close succession in time or in close proximity in area. Also, research on CDP is limited even for the worldwide literature. Therefore, the purposes of this paper are to synthesize recent literature concerning the risks of CDP, and to provide examples of past occurrences, with a focus on the Canadian Prairies. Since literature from the Prairies is limited, global work is also reviewed. That literature indicates increasing concern and interest in CDP. Relationships between drought and pluvials are also characterized using the SPEI Global Monitor for the Prairies, emphasizing the recent past. Research mostly considers drought and pluvials as separate events in the Prairies, but is integrated here to characterize the relationships of these extremes. The spatiotemporal patterns showed that several of the extreme to record pluvials were found to be closely associated with extreme droughts in the Prairies. The intensities of the extremes and their dry to wet boundaries were described. This is the first research to explore the concept of and to provide examples of CDP for the Prairies and for Canada. Examples of CDP provide insights into the regional hydroclimatic variability. Furthermore, most literature on future projections strongly suggests that this variability is likely to increase, mainly driven by anthropogenic climate change. Therefore, improved methods to characterize and to quantify CDP are required. These findings suggest means of decreasing vulnerability and associated damages. Although the study area is the Canadian Prairies, the work is relevant to other regions that are becoming more vulnerable to increasing risks of and vulnerabilities to such compound extremes. [ABSTRACT FROM AUTHOR]

Global warming and climate variations are expected to alter hydrologic conditions and exacerbate flooding, primarily through increasingly frequent and intense storm events and sea-level rise. The interactions between coastlines and their inhabitants around the world are highly diverse, making them challenging to model due to the non-homogeneous, nonlinear, and complex nature of human decision-making. Agent-based modeling has proven valuable in various fields, enabling researchers to explore various social phenomena and emergent patterns under different institutional frameworks, including climate change scenarios and policy decisions, particularly at local scales. This approach is particularly useful in providing insights into possible outcomes and feedback resulting from the convergence of individual- and community-level adaptation decisions, and it has increasingly been used to model coastal systems. However, there are a limited number of studies that examine the effects of climate adaptation decisions on coastal tourism systems. This paper aims to address this gap by first providing an overview of the current state of agent-based modeling literature that explores coastal community adaptation responses to climate change. Subsequently, the paper argues for the application of these methods to simulate the effects of adaptation on coastal tourism dynamics. To better capture the interactions within subsystems and potential redistributed effects inherent in multi-scale and multi-stakeholder decision-making processes within these systems, we propose integrating agent-based modeling with a novel system of socio-environmental systems (SoSES) approach. This integration aims to assist city planners, policymakers, stakeholders, and attraction managers in effectively assessing adaptation options to safeguard their communities from the multifaceted impacts of climate change. [ABSTRACT FROM AUTHOR]

Holding a lasting balance between the water resources and water demands has become a challenging task for water resources managers, especially in recent years with the looming global warming crisis and its resulting climatic change effects. This paper focuses on modeling the optimized operation of the Zayandehrud Reservoir, located in west-central Iran, under two fifth-generation climate change scenarios called RCP4.5 and RCP8.5. A novel variant of the gravitational search algorithm (GSA), named the adaptive accelerated GSA (AAGSA) is proposed and adopted as the optimizer of the reservoir operation in this paper. The major advancement of the AAGSA against the original GSA is its high exploration capability, allowing the proposal to effectively tackle a variety of difficulties any complex optimization problem can face. The goal of the optimization process is the maximization of the sustainability of supplying the downstream water demands by the reservoir. The optimal results obtained by the original GSA and the proposed AAGSA algorithms suggest that the AAGSA can achieve much more accurate results with much less computational runtime, such that the proposed AAGSA is able to achieve the reservoir operation sustainability index of 98.53% and 99.46%, under RCP4.5 and RCP8.5 scenarios, respectively. These figures are higher than those obtained by the original GSA by 23.5% and 16% under RCP4.5 and RCP8.5, respectively, while the runtime of the proposal is reduced by over 80% in both scenarios, as compared to the GSA, suggesting the high competence of the proposed AAGSA to solve such a high-dimensional and complex real-world engineering problem. [ABSTRACT FROM AUTHOR]

Climate change and human activities are two important factors in the changing environment that affect the variability of the hydrological cycle and river regime in the Yalong River basin. This paper analyzed the hydrological alteration and extremes in the Yalong River basin based on multi-source satellite data, and projected the hydrological response under different future climate change scenarios using the CwatM hydrological model. The results show that: (1) The overall change in hydrological alteration at Tongzilin station was moderate during the period of 1998–2011 and severe during the period of 2012–2020. (2) Precipitation (average 781 mm/a) is the dominant factor of water cycle on a monthly scale, which can explain the temporal variability of runoff, evaporation, and terrestrial water storage, while terrestrial water storage is also simultaneously regulated by runoff and evaporation. (3) The GRACE data are comparable with regional water resource bulletins. The terrestrial water storage is mainly regulated by surface water (average 1062 × 108 m3), while the contribution of groundwater (average 298 × 108 m3) is relatively small. (4) The evaporation and runoff processes will intensify in the future due to climate warming and increasing precipitation (~10%), and terrestrial water storage will be depleted. The magnitude of change will increase with the enhancement of emission scenarios. [ABSTRACT FROM AUTHOR]

Global warming is causing an intensification of extreme climate events with significant changes in frequency, duration, and intensity over many regions. Understanding the current and future influence of this warming in northeastern Brazil (NEB) is important due to the region's greater vulnerability to natural disasters, as historical records show. In this paper, characteristics of climate change projections (precipitation and air temperature) over NEB are analyzed using 15 models of Coupled Model Intercomparison Project Phase 6 (CMIP6) under four Shared Socioeconomic Pathways (SSPs: SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) scenarios. By using the Taylor diagram, we observed that the HadGEM3-GC31-MM model simulates the seasonal behavior of climate variables more efficiently. Projections for NEB indicate an irreversible increase in average air temperature of at least 1 °C throughout the 21st century, with a reduction of up to 30% in annual rainfall, as present in scenarios of regional rivalry (SSP3-7.0) and high emissions (SSP5-8.5). This means that a higher concentration of greenhouse gases (GHG) will increase air temperature, evaporation, and evapotranspiration, reducing rainfall and increasing drought events. The results obtained in this work are essential for the elaboration of effective strategies for adapting to and mitigating climate change for the NEB. [ABSTRACT FROM AUTHOR]

In the context of global warming, the melting of glaciers in the Tien Shan Mountains as the important "solid reservoir" in the arid area of Central Asia is accelerating in recent decades, leading to profound changes in regional water resources. Based on the simulated glaciological data from the Python Glacier Evolution Model (PyGEM) and the measured glaciological data from the World Glacier Monitoring Service (WGMS), this paper analyzed the applicability of simulated data, the changes in glacier mass balance, and the responses of the glacier to climate change and its impacts on glacier runoff in the Tien Shan Mountains. The results show that (1) the PyGEM simulation dataset is in good agreement with the measurements, which can effectively reproduce the change in the glacier mass balance in the Tien Shan Mountains glaciers and is suitable for studying the regional scale glacier change. (2) From 1980 to 2016, the decadal average mass balance change rate of glaciers in the Tien Shan Mountains was −0.012 m w.e. yr−1. The regional mass balance showed an overall negative increasing trend (the area with increasingly negative accounted for 80.13% of the entire area), with a positive increase that only occurred in the West Tien Shan Mountains and western North Tien Shan Mountains (19.87%). (3) The correlation between the temperature and mass balance is much higher than that between the precipitation and mass balance. Temperature dominates the change and development of regional glaciers. The increase in negative glacier mass balance that was observed in the study area is mainly affected by the rising temperature, the decreasing solid precipitation in the accumulation period, and the rapid melting in the ablation period. (4) The glacier runoff in the six representative rivers showed an increasing trend. The contribution rate of glacier runoff to river runoff changed significantly after 2000 but differed among rivers. Overall, the larger the glacier area in the source region is, the greater the contribution rate of glacier runoff is, and the more the contribution rate continuously increases or fluctuates; otherwise, the contribution rate keeps declining, which means the runoff peak may have passed and future runoff may decrease. [ABSTRACT FROM AUTHOR]

The Wadi El-Rayan lakes are important aquatic environments located at the border of the great North African Sahara. Quantifying the temporal changes in these lakes due to natural and/or anthropogenic stressors is critical when assessing potential impacts on aquatic ecosystem health and the sustainability of fisheries. To detect the changes in fish communities and their drivers, the landing composition of the Wadi El-Rayan lakes over the past 30 years was quantitatively analyzed. The areas of the lakes dramatically decreased from 110 km2 in 1991 to 73 km2 in 2019. The loss of the lake area was attributed to climate warming, where the evaporation rate exceeded the volume of recharge and the recharge decreased due to an increase in agriculture and aquaculture. The total landing significantly increased in the past three decades due to an increase in the fishing effort (number of licensed boats). Nile tilapia, mullet, and grass carp dominated the landings. The pelagic-to-demersal ratio indicated a shift in the fish community composition towards demersal species. This shift was attributed to an increase in the eutrophication level. The fish communities of the landing data were clustered into four distinct groups. These clusters were significantly differentiated (p < 0.001) in both a PERMANOVA test and a PCA plot. There was a gradual replacement of the dominant species among these clusters. The most recent cluster (2018–2019) was characterized by rare species dominating the community. This shift in species composition suggests that target taxa may have been overexploited. The total landing also decreased, which may have been a result of climate warming. Furthermore, the presence of alien and warm-water species significantly increased. The fish community structure and composition shift could be attributed to anthropogenic (mismanagement) and natural climatic changes (warming). [ABSTRACT FROM AUTHOR]

The variations in snow cover on the Tibetan Plateau play a pivotal role in comprehending climate change patterns and governing hydrological processes within the region. This study leverages daily snow cover data and the NASA Digital Elevation Model (DEM) from 2003 to 2020 to analyze spatiotemporal snow cover days and assess their responsiveness to climatic shifts by integrating meteorological data. The results reveal significant spatial heterogeneity in snow cover across the Plateau, with a slight decreasing trend in annual average snow cover duration. Snow cover is predominantly observed during the spring and winter seasons, constituting approximately 32% of the total snow cover days annually. The onset and cessation of snow cover occur within a range of 120–220 days. Additionally, an increasing trend in snow cover duration below 5000 m altitude was observed, in addition to a decreasing trend above 5000 m altitude. Sub-basin analysis delineates the Tarim River Basin as exhibiting the lengthiest average annual snow cover duration of 83 days, while the Yellow River Basin records the shortest duration of 31 days. The decreasing trend in snow cover duration closely aligns with climate warming trends, characterized by a warming rate of 0.17 ± 0.54 °C per decade, coupled with a concurrent increase in precipitation at a rate of 3.09 ± 3.81 mm per year. Temperature exerts a more pronounced influence on annual snow cover duration variation compared to precipitation, as evidenced by a strong negative correlation (CC = −0.67). This study significantly augments the comprehension of hydrological cycle dynamics on the Tibetan Plateau, furnishing essential insights for informed decision-making in water resource management and ecological conservation efforts. [ABSTRACT FROM AUTHOR]

The instability of the river channels has increased in response to the combined effects of global warming and human activity. This instability threatens the lives and property of people who live along river courses. This study takes the Pingluo section of the upper Yellow River, which is ~28 km long and ~400 m wide, as its research focus. We studied 11 periods of Landsat remote sensing images from 1973 to 2023 and analyzed the evolutionary characteristics of the Pingluo section over the past 50 years. The channel morphology indices included the channel braiding index (BIT), the bar braiding index (BIB), the average area of the bar (Ab), and the width of the wet channel area (BW). The results showed that there was an overall shrinking trend in this section of the Yellow River; more particularly, fluctuations in indicators such as the river width and the braiding index highlighted an increasing–decreasing–increasing pattern of change. During the 1973–1986 period, the river showed a widening trend, with narrow anabranches cutting through the floodplain and both the river width and the braiding index increasing dramatically over a short period. Over the 1986–2018 period, the area of the wet channel continued to shrink to its lowest level for the past 50 years, the river's branches were diverted and abandoned, and the channel tended to straighten out. Between 2018 and 2023, the river showed a slightly expanding trend. The evolution of the river channel appears to be related to regional human activity and climate change. For example, after the joint filling of the Longyangxia and Liujiaxia reservoirs in the upper reaches of the Pingluo section of the Yellow River in 1986, runoff and sediment load along this section decreased, flood events became less frequent, and the channel tended to contract. In addition, the increase in extreme precipitation events over the last five years has led to an increase in the magnitude and frequency of peak discharge values in the region, which is the main reason for the increase in the river braiding index and area. [ABSTRACT FROM AUTHOR]

Under the combined impacts of climate change and human activities, a series of water issues, such as water shortages, have arisen all over the world. According to current studies in Science and Nature, water security has become a frontier critical topic. Water supply security (WSS), which is the state of water resources and their capacity and their capacity to meet the demand of water users by water supply systems, is an important part of water security. Currently, WSS is affected by the amount of water resources, water supply projects, water quality and water management. Water shortages have also led to water supply insecurity. WSS is now evaluated based on the balance of the supply and demand under a single water resources condition without considering the dynamics of the varying conditions of water resources each year. This paper developed an optimal allocation model for water resources that can realize the optimal allocation of regional water resources and comprehensively evaluate WSS. The objective of this model is to minimize the duration of water shortages in the long term, as characterized by the Water Supply Security Index (WSSI), which is the assessment value of WSS, a larger WSSI value indicates better results. In addition, the simulation results of the model can determine the change process and dynamic evolution of the WSS. Quanzhou, a city in China with serious water shortage problems, was selected as a case study. The allocation results of the current year and target year of planning demonstrated that the level of regional comprehensive WSS was significantly influenced by the capacity of water supply projects and the conditions of the natural water resources. The varying conditions of the water resources allocation results in the same year demonstrated that the allocation results and WSSI were significantly affected by reductions in precipitation, decreases in the water yield coefficient, and changes in the underlying surface. [ABSTRACT FROM AUTHOR]

Spring algal blooms in mid–high-latitude lakes are facing serious challenges such as earlier outbreaks, longer duration, and increasing frequency under the dual pressure of climate warming and human activities, which threaten the health of freshwater ecosystems and water security. At present, the freeze-thaw processes is the key to distinguishing spring algal blooms in mid- to high-latitude lakes from low-latitude lakes. Based on the visualization and an analysis of the literature in the WOS database during 2007–2023, we clarified the driving mechanism of the freeze-thaw process (freeze-thaw, freeze-up, and thawing) on spring algal bloom in lakes by describing the evolution of the freeze-thaw processes on the nutrient migration and transformation, water temperature, lake transparency and dissolved oxygen, and physiological characteristics of algae between shallow lakes and deep lakes. We found that the complex phosphorus transformation process during the frozen period can better explain the spring-algal-bloom phenomenon compared to nitrogen. The dominant species of lake algae also undergo transformation during the freeze-thaw process. On this basis, the response mechanism of spring algal blooms in lakes to future climate change has been sorted out. The general framework of "principles analysis, model construction, simulation and prediction, assessment and management" and the prevention strategy for dealing with spring algal bloom in lakes have been proposed, for which we would like to provide scientific support and reference for the comprehensive prevention and control of spring algal bloom in lakes under the freezing and thawing processes. [ABSTRACT FROM AUTHOR]

Global warming has become indisputable in recent years; however, the mechanisms by which water vapor, radiation, and greenhouse gases such as carbon dioxide contribute to driving global warming remain unclear, and it is becoming increasingly important to clarify their respective effects on temperature warming. In this study, we used the Global Land Data Assimilation System (GLDAS) datasets and National Oceanic and the Atmospheric Administration (NOAA) Global Monitoring Laboratory (GML) data to investigate the spatiotemporal variation characteristics of global warming and its driving mechanisms. The effects of water vapor, radiation (net longwave radiation), and CO2 on temperature rise are quantified from the perspective of the coupled land–atmosphere system, and water vapor is characterized in terms of the vapor pressure deficit (difference between saturated and actual water vapor pressures) to explicitly characterize its impact on the global water–heat cycle. The results show the following: (1) Under significant global warming, the vapor pressure deficit (VPD) exhibits an increasing trend, which is attributed to the rate of increase in actual water vapor being relatively slower than saturated water vapor. (2) Compared with the significant positive contribution of water vapor to global warming, CO2 is not, as generally expected, the most critical greenhouse gas causing global warming. (3) Water vapor and net longwave radiation (NLR) have significant mutual feedbacks on global warming. (4) A remarkable complementary mechanism of global warming that involves water vapor and NLR was identified, whereby the increased saturated water vapor induced by the rising temperature dominates the decrease in NLR. The results from this study have important theoretical value by enabling a more complete understanding of the contribution of VPD to global climate change and shedding light on the large-scale water vapor–climate change mutual feedback mechanism through research. [ABSTRACT FROM AUTHOR]

In this study, an ensemble of numerical simulations with a state-of-the-art hydrodynamic model for coastal applications is used to characterize, for the first time, the expected mid-21st-century changes in circulation and associated sea-level height inside the Venice lagoon induced by projected Mediterranean sea level rise and atmospheric circulation changes over the Adriatic Sea under the RCP8.5 emission scenario. Our results show that water transports through the three inlets connecting the Venice lagoon to the open sea are expected to change significantly, with consequent significant persistent alterations of the circulation and sea-level height inside the lagoon. The projected water mass redistributions motivate further studies on the implications of climate change for the lagoon environment. [ABSTRACT FROM AUTHOR]

The purpose of this study was to elucidate the patterns and mechanisms driving seasonal and interannual variations of carbon and nitrogen stable isotopes in the zooplankton crustacean community of Lake Maggiore (Italy), during the period 2009–2020. Different zooplankton taxa and groups showed different ranges of δ13C signatures, giving an insight into food sources and niche partition. In particular, cyclopoids had a restricted range with more negative δ13C‰ values and an increase in δ13C fractionation with the establishment of water thermal vertical stratification, highlighting the importance of vertical distribution as a key factor for taxa coexistence in a vertically heterogenous environment. The δ13C values of the zooplankton community and of Daphnia were positively related to water temperature (R2 = 0.58 p < 0.0001 and R2 = 0.68 p < 0.0001, respectively), and the δ13C Daphnia signature was positively related to chlorophyll a (R2 = 0.32, p < 0.0001). Decomposition of the time-series data for zooplankton carbon and nitrogen signatures and environmental parameters identified increasing trends in water temperature, chlorophyll a and water conductivity and a decrease in nitrate that matched changes in carbon isotopic signature trends in some zooplankton taxa (Bosmina, Daphnia and Diaptomids). Overall, the observed patterns in zooplankton isotopic signatures were interpreted as integrations of the effects of climate warming in Lake Maggiore, affecting both the availability of food sources and environmental conditions. [ABSTRACT FROM AUTHOR]

This paper characterizes non-indigenous fish species (NIS) and analyses both atmospheric and sea surface temperatures for the Mediterranean coast of Egypt from 1991 to 2020, in relation to previous reports in the same areas. Taxonomical characterization depicts 47 NIS from the Suez Canal (Lessepsian/alien) and 5 from the Atlantic provenance. GenBank accession number of the NIS mitochondrial gene, cytochrome oxidase 1, reproductive and commercial biodata, and a schematic Inkscape drawing for the most harmful Lessepsian species were reported. For sea surface temperatures (SST), an increase of 1.2 °C to 1.6 °C was observed using GIS software. The lack of linear correlation between annual air temperature and annual SST at the same detection points (Pearson r) could suggest a difference in submarine currents, whereas the Pettitt homogeneity test highlights a temperature breakpoint in 2005–2006 that may have favoured the settlement of non-indigenous fauna in the coastal sites of Damiette, El Arish, El Hammam, Alexandria, El Alamain, and Mersa Matruh, while there seems to be a breakpoint present in 2001 for El Sallum. This assessment of climate trends is in good agreement with the previous sightings of non-native fish species. New insights into the assessment of Egyptian coastal climate change are discussed. [ABSTRACT FROM AUTHOR]

Mt. Munkhkhairkhan is the most crucial region for understanding climate and glaciation changes in Mongolia. This study investigated the relationship between glacial area changes and the climate elements of Mt. Munkhkhairkhan in the Mongolian-Altai Mountains using a remote sensing approach, in-situ observations, the Mann–Kendall (MK) test, Innovative Trend Analysis Method (ITAM), Sen's slope estimator test, and statistical analysis. The study results showed that for the last 30 years, the annual average air temperature of Mt. Munkhkhairkhan has been slightly increasing. Total annual precipitation (mainly snow) in the mountain area decreased from 1990 to 2000, but since 2000, a significant increase in precipitation levels has appeared. For the last 30 years, the glacial area has decreased by 32% to 11.7 km2. Multiple regression results showed a strong correlation between Temperature, Precipitation, and Glaciers (Multiple R = 0.69, R2 = 0.48). Ruther indicated that Temperature (t = −2.332, p = 0.036) and Precipitation (t = −3.212, p = 0.007) were significant predictors in the model. Air temperature and precipitation explained 48 percent of the change in the glacier area, and R = 0.69 is a strong correlation. The glaciers and snow area in the study area have changed due to climate warming and precipitation changes and are located in arid and semi-arid regions of Central Asia. This study of Mt. Munkhairkhan shows that climate change significantly impacts glaciers and snow. [ABSTRACT FROM AUTHOR]

Global warming affects, among many other things, groundwater recharge conditions. Over recent decades, this phenomenon in the Carpathians has been emphasized by the changing role of snowmelt recharge in winter and spring. The aim of the study was to assess baseflow trends in 20 medium-sized Carpathian catchments in Poland and Slovakia. The baseflow was calculated using Eckhardt's digital filter. The trend analysis was performed using the non-parametric method separately for the series representing the baseflow throughout the whole year, and separately for seasons. The most evident changes were noted for the low baseflow in the summer and autumn, especially in foothill catchments. Statistically significant decreases in the low daily baseflow were expressed as a relative change, and ranged from −9% to −66% per 10 years for the summer, and from −12% to −82% per 10 years for the autumn. In winter and spring, trends in the low baseflow were not significant, except in high mountain catchments where 14% of increases in the low baseflow were noted in the winter and spring. The results indicate the changing role of snowmelt recharge in the Carpathians and the increasing problem of groundwater depletion in the summer and autumn, mainly in foothill areas. [ABSTRACT FROM AUTHOR]

Climate change leads to the increase of frequency and intensity for extreme precipitation events, potentially threatening the development of our society. It is of great significance to study the spatiotemporal variation of precipitation for understanding cycle process of water and its response to global warming. This paper selects the Xijiang River basin, which locates on a low latitude and coastland, as the research area. The spatiotemporal distribution and homogeneity of precipitation are analyzed, and the spatial trend is studied using 12 extreme precipitation indices. Finally, chaotic characteristics are evaluated for daily precipitation. The results showed that the precipitation in the basin tended to be unevenly distributed. On wet days, precipitation in the middle and the west was more and more uniform. The proportion of tiny rain was the largest, between 33.5% and 41.3%. The proportion of violent rain was the smallest, between 0.1% and 4.7%. Duan had the highest frequency for violent rain, and the probability of disasters caused by extreme precipitation near the station was the highest. The simple daily intensity index (SDII) showed a significant increase in the middle and the northeast. PRCPTOT (annual total wet-day precipitation) showed a decreasing trend in the northwest. The average rates of variation for R95PTOT (precipitation on very wet days) and R99PTOT (precipitation on extremely wet days) were −0.01 mm/year and 0.06 mm/year, respectively. There might be a risk of drought on the west of the basin in the future. Precipitation in other locations was still relatively abundant. Daily precipitation showed high dimension and high chaotic characteristics. The MED (minimum embedding dimension) was between 11 and 30, and the MLE (largest Lyapunov exponent) was between 0.037 and 0.144. [ABSTRACT FROM AUTHOR]

Reliable projections of evapotranspiration (ET) are important for agricultural and water resources development, planning, and management. However, ET projections using well established empirical models suffer from uncertainty due to their dependency on many climatic variables. This study aimed to develop temperature-based empirical ET models using Gene Expression Programming (GEP) for the reliable estimation and projection of ET in peninsular Malaysia within the context of global warming. The efficiency of the GEP-generated equation was compared to the existing methods. Finally, the GEP ET formulas were used to project ET from the downscaled and projected temperature of nine global climate models (GCMs) for four Representative Concentration Pathways (RCPs), namely, RCP 2.6, 4.5, 6.0, and 8.5, at ten locations of peninsular Malaysia. The results revealed improved performance of GEP models in all standard statistics. Downscaled temperatures revealed a rise in minimum and maximum temperatures in the range of 2.47–3.30 °C and 2.79–3.24 °C, respectively, during 2010–2099. The ET projections in peninsular Malaysia showed changes from −4.35 to 7.06% for RCP2.6, −1.99 to 16.76% for RCP4.5, −1.66 to 22.14% for RCP6.0 and −0.91 to 39.7% for RCP8.5 during 2010−2099. A higher rise in ET was projected over the northern peninsula than in the other parts. [ABSTRACT FROM AUTHOR]

The Mediterranean region is increasingly recognized as a climate change hotspot but is highly underrepresented in hydrological climate change studies. This study aims to investigate the climate change effects on the hydrology of Lakhmass catchment in Tunisia. Lakhmass catchment is a part of the Medium Valley of Medjerda in northwestern Tunisia that drains an area of 126 km². First, the Hydrologiska Byråns Vattenbalansavdelning light (HBV-light) model was calibrated and validated successfully at a daily time step to simulate discharge during the 1981–1986 period. The Nash Sutcliffe Efficiency and Percent bias (NSE, PBIAS) were (0.80, +2.0%) and (0.53, −9.5%) for calibration (September 1982–August 1984) and validation (September 1984–August 1986) periods, respectively. Second, HBV-light model was considered as a predictive tool to simulate discharge in a baseline period (1981–2009) and future projections using data (precipitation and temperature) from thirteen combinations of General Circulation Models (GCMs) and Regional Climatic Models (RCMs). We used two trajectories of Representative Concentration Pathways, RCP4.5 and RCP8.5, suggested by the Intergovernmental Panel on Climate Change (IPCC). Each RCP is divided into three projection periods: near-term (2010–2039), mid-term (2040–2069) and long-term (2070–2099). For both scenarios, a decrease in precipitation and discharge will be expected with an increase in air temperature and a reduction in precipitation with almost 5% for every +1 °C of global warming. By long-term (2070–2099) projection period, results suggested an increase in temperature with about 2.7 °C and 4 °C, and a decrease in precipitation of approximately 7.5% and 15% under RCP4.5 and RCP8.5, respectively. This will likely result in a reduction of discharge of 12.5% and 36.6% under RCP4.5 and RCP8.5, respectively. This situation calls for early climate change adaptation measures under a participatory approach, including multiple stakeholders and water users. [ABSTRACT FROM AUTHOR]

In this paper, the impact of climate change on the climate and discharge of the Dez Dam Basin and the hydropower potential of two hydropower plants (Bakhtiari and Dez) is investigated based on the downscaled outputs of six GCMs (General Circulation Models) and three SRES (Special Report on Emission Scenarios) scenarios for the early, mid and late 21st century. Projections of all the scenarios and GCMs revealed a significant rise in temperature (up to 4.9 °C) and slight to moderate variation in precipitation (up to 18%). Outputs of the HBV hydrologic model, enforced by projected datasets, show a reduction of the annual flow by 33% under the climate change condition. Further, analyzing the induced changes in the inflow and hydropower generation potential of the Bakhtiari and Dez dams showed that both inflow and hydropower generation is significantly affected by climate change. For the Bakhtiari dam, this indicates a consistent reduction of inflow (up to 27%) and electricity generation (up to 32%). While, in the Dez dam case, the inflow is projected to decrease (up to 22%) and the corresponding hydropower is expected to slightly increase (up to 3%). This contrasting result for the Dez dam is assessed based on its reservoir and hydropower plant capacity, as well as other factors such as the timely releases to meet different demands and flow regime changes under climate change. The results show that the Bakhtiari reservoir and power plant will not meet the design-capacity outputs under the climate change condition as its large capacity cannot be fully utilized; while there is room for the further development of the Dez power plant. Comparing the results of the applied GCMs showed high discrepancies among the outputs of different models. [ABSTRACT FROM AUTHOR]

In northern regions, like Finland, peak river discharge is principally controlled by maximum snowmelt runoff during spring (March–May). Global warming and climate change extensively influence both the quantity and temporal characteristics of peak discharge in northern rivers by altering snowpack accumulation and melt processes. This study analyzed peak spring flood discharge (PSFD) magnitude (PSFDM) and timing (PSFDT) in four natural rivers (Simojoki, Kuivajoki, Kiiminkijoki, and Temmesjoki) across northern Finland, in terms of long-term (1967–2011) variability, trends, and links to large-scale climate teleconnections. The PSFDM significantly (p < 0.05) declined in the Simojoki, Kuivajoki, and Kiiminkijoki rivers over time. Both the Simojoki and Kuivajoki rivers also experienced significant decreasing trends of about −0.33 and −0.3 (days year−1), respectively, in the PSFDT during 1967–2011. In these two rivers, the less and earlier PSFDs were principally attributable to the warmer spring seasons positively correlated with the North Atlantic Oscillation (NAO) in recent decades. Moreover, daily precipitation time series corresponding to the PSFD events showed no considerable effects on PSFDM and PSFDT changes in all the natural rivers studied. This suggests that less and earlier historical PSFDs in natural rivers at higher latitudes in northern Finland were primarily induced by warmer springtime temperatures influencing snowpack dynamics. [ABSTRACT FROM AUTHOR]

A simple scaling analysis was performed in Andalusia (Spain) using daily records from 377 selected stations covering the temporal period between 1870 and 2018. Since Andalusia is a region of considerable climatic variety, with notably wet areas as well as extremely dry zones, this study is useful to investigate the relationship between the simple scaling parameter value and the characteristic rainfall regime of a place. Despite the great correspondence with the average annual precipitation (PRCPTOT), a clear dependence on rainfall irregularity was observed, revealed by the ratio of the maximum daily precipitation and PRCPTOT, as well the wet spells frequency index CWD. The spatial distribution of the simple scaling parameter captured the increasing influence of the Mediterranean Sea towards the East. The easternmost dry areas are clearly influenced by Mediterranean disturbances, with a high proportion of convective rainfall and an irregular rainfall pattern. Using a simple scaling parameter, the generalized equations of the intensity-duration-frequency (IDF) curves, of great hydrological interest were calculated for the eight Andalusian provincial capitals. Moreover, the temporal trends of this parameter in the four past decades were studied in the different areas with the aim of determining if changes in their rainfall patterns due to global warming could be detected. [ABSTRACT FROM AUTHOR]

For rivers and streams, the impact of rising water temperature on biochemical oxygen demand (BOD) assimilative capacity depends on the interplay of two independent factors: the waterbody's dissolved oxygen (DO) saturation and its self-purification rate (i.e., the balance between BOD oxidation and reaeration). Although both processes increase with rising water temperatures, oxygen depletion due to BOD oxidation increases faster than reaeration. The net result is that rising temperatures will decrease the ability of the world's natural waters to assimilate oxygen-demanding wastes beyond the damage due to reduced saturation alone. This effect should be worse for nitrogenous BOD than for carbonaceous BOD because of the former's higher sensitivity to rising water temperatures. Focusing on streams and rivers, the classic Streeter–Phelps model was used to determine the magnitude of the maximum or "critical" DO deficit that can be calculated analytically as a function of the mixing-point BOD concentration, DO saturation, and the self-purification rate. The results indicate that high-velocity streams will be the most sensitive to rising temperatures. This is significant because such systems typically occur in mountainous regions where they are also subject to lower oxygen saturation due to decreased oxygen partial pressure. Further, they are dominated by salmonids and other cold-water fish that require higher oxygen levels than warm-water species. Due to their high reaeration rates, such systems typically exhibit high self-purification constants and consequently have higher assimilation capacities than slower moving lowland rivers. For slow-moving rivers, the total sustainable mixing-point concentration for CBOD is primarily dictated by saturation reductions. For faster flowing streams, the sensitivity of the total sustainable load is more equally dependent on temperature-induced reductions in both saturation and self-purification. [ABSTRACT FROM AUTHOR]

In running waters, under climate change conditions, the combined effect of water warming and decreasing flow rates may encourage colonisation by invasive cool and warm-water fish species. The aim of the study was to analyze the potential climate change effects on the spread of four invasive alien fishes in the Tiber River basin, taking into account the effects of river fragmentation. Fish and environmental data collected in 91 sites over the years 1998–2018, were used to analyze temporal changes in their habitat requirements. A multivariate analysis was conducted, and the hypothesis of a range expansion towards the upstream reaches has been tested. For Barbus barbus, Gobio gobio, Padogobius bonelli and Pseudorasbora parva population abundances and body condition were analyzed. Detectability, occupancy, local extinction and colonization probabilities were estimated. We showed that B. barbus and P. bonelli have significantly extended their range toward upstream. P. parva did not move toward higher altitudes significantly, suggesting that, at this stage, the species has probably reached an equilibrium. River fragmentation, elevation, water temperature and average current speed seem to be major determinants in colonization processes, affecting the dispersal ability of the species. Not surprisingly for species introduced in relatively recent times, the colonization probabilities were much higher than extinction probabilities. Our results provided evidence for some synergistic effects between climate changes and alien fish species invasions, in terms of species range shifts mediated by rising water temperatures, although they should be interpreted cautiously, taking into account that these species most likely were not yet stabilized. [ABSTRACT FROM AUTHOR]

The average global temperature is predicted to increase by 3 °C by the end of this century due to human-induced climate change. The overall metabolism of the aquatic biota will be directly affected by rising temperatures and associated changes. Since thermal stability is a characteristic of groundwater ecosystems, global warming is expected to have a profound effect on the groundwater fauna. The prediction that stygobitic (obligate groundwater dweller) species are vulnerable to climate change includes assumptions about metabolic effects that can only be tested by comparisons across a thermal gradient. To this end, we investigated the effects of two different thermal regimes on the metabolism of the stygobitic copepod species Diacyclops belgicus (Kiefer, 1936). We measured the individual-based oxygen consumption of this species as a proxy of possible metabolic reactions to temperature rising from 14 to 17 °C. We used a sealed glass microplate equipped with planar oxygen sensor spots with optical isolation glued onto the bottom of 80-μL wells integrated with a 24-channel fluorescence-based respirometry system. The tests have provided controversial results according to which the D. belgicus populations should be prudently considered at risk under a global warming scenario. [ABSTRACT FROM AUTHOR]

Oceans/Seas are important components of Earth that are affected by global warming and climate change. Recent studies have indicated that the deeper oceans are responsible for climate variability by changing the Earth's ecosystem; therefore, assessing themhas becomemore important. Remote sensing can provide sea surface data at high spatial/temporal resolution and with large spatial coverage, which allows for remarkable discoveries in the ocean sciences. The deep layers of the ocean/sea, however, cannot be directly detected by satellite remote sensors. Therefore, researchers have examined the relationships between salinity, height, and temperature of the oceans/Seas to estimate their subsurface water temperature using dynamical models and model-based data assimilation (numerical based and statistical) approaches, which simulate these parameters by employing remotely sensed data and in situ measurements. Due to the requirements of comprehensive perception and the importance of global warming in decision making and scientific studies, this review provides comprehensive information on the methods that are used to estimate ocean/sea subsurface water temperature from remotely and non-remotely sensed data. To clarify the subsurface processes, the challenges, limitations, and perspectives of the existing methods are also investigated. [ABSTRACT FROM AUTHOR]

In order to simulate food web responses of small boreal lakes to changes in thermal stratification due to global warming, a 4 year whole-lake manipulation experiment was performed. Within that time, period lake mixing was intensified artificially during two successive summers. Complementary data from a nearby lake of similar size and basic water chemistry were used as a reference. Phytoplankton biomass and chlorophyll a did not respond to the greater mixing depth but an increase was observed in the proportional abundance of diatoms, and the proportional abundance of cryptophytes also increased immediately after the onset of mixing. Obligate anoxic green sulphur bacteria vanished at the onset of mixing but gradually recovered after re-establishment of hypolimnetic anoxic conditions. No major effect on crustacean zooplankton was found, but their diversity increased in the metalimnion. During the mixing, the density of rotifers declined but protozoan density increased in the hypolimnion. Littoral benthic invertebrate density increased during the mixing due to Ephemeroptera, Asellus aquaticus and Chironomidae, whereas the density of Chaoborus larvae declined during mixing and lower densities were still recorded one year after the treatment. No structural changes in fish community were found although gillnet catches increased after the onset of the study. The early growth of perch (Perca fluviatilis) increased compared to the years before the mixing and in comparison to the reference lake, suggesting improved food availability in the experimental lake. Although several food web responses to the greater mixing depth were found, their persistence and ecological significance were strongly dependent on the extent of the disturbance. To better understand the impacts of wind stress on small lakes, long term whole-lake experiments are needed. [ABSTRACT FROM AUTHOR]

Low carbon policies, including those aimed at increasing water efficiency, have been adopted as a crucial strategy for combating global warming and climate change. The green building evaluation system used in Taiwan was first applied in 1999 and initially utilized a building's water efficiency as the threshold index for determining the building's environmental impact. Since 1999, more than a thousand buildings have been certified as green buildings using this evaluation system. The quantitative effects of water conservation efforts should be provided to policy makers as a form of positive feedback. To that end, the present study offers a calculation process for estimating the quantitative volume of water saved by practical green buildings. The baseline water usage for all kinds of buildings was determined to serve as the criterion for determining the water-saving efficiency of individual buildings. An investigation of the average water-saving rate from 2000 to 2013 for 1320 buildings certified as green buildings was also conducted to validate the estimation results and found that these green buildings saved an average of approximately 37.6% compared to the baseline water usage rate for all buildings. Water savings will inevitably follow from the use of water-saving appliances or water-saving designs for buildings. The proposed calculation process can be used to clarify the relationships between specific water-saving concepts and the real water usage efficiency of green buildings. [ABSTRACT FROM AUTHOR]

Climate change can affect freshwater communities superimposing on other major stressors, such as water exploitation, with effects still poorly understood. The exacerbation of naturally-occurring periods of low flows has been reported as a major hydrological effect of water diversions, with severe impacts on river benthic macroinvertebrate communities. This study aimed at assessing long-term modifications of low-flow events in a large lowland Italian river possibly associated to climate change and the effects of these events, intensified by water withdrawals, on benthic macroinvertebrates. A 77-year dataset on daily discharge was thus analyzed through Mann-Kendall test and Sen's method to investigate modifications of the main hydrological parameters. Moreover, macroinvertebrates were collected during the low-flow periods that occurred from 2010 to 2015 at three sites downstream of water withdrawals, representing three different conditions of hydrological impairment. After assessing possible differences in taxonomical and functional composition between sites and impairment conditions, redundancy analysis and ordinary least squares regression were performed to link benthos metrics to environmental (hydrological and physico-chemical) characteristics. An increase in the duration of the low-flow periods and reduced summer flows were detected on the long term, and the magnitude of low flows was significantly altered by water withdrawals. These hydrological features shaped both structural and functional characteristics of benthic assemblages, highlighting the need for a more environmentally-sustainable water resource management in the current context of climate change. [ABSTRACT FROM AUTHOR]

Climate change resulting from global warming has an increasing impact on Earth. The resulting sea level rise is starting to be noticed in some regions today, and based on projections, could have severe consequences in the future. These consequences would primarily be felt by residents of coastal areas, but through the potential for irreparable damage to cultural heritage sites, could be significant for the general public. The primary aim of the research undertaken in this article was to assess the threat to cultural heritage objects on the case study area of Tri-City, Poland. A review of available elevation data sources for their potential use in analyses of sea level changes was required. The selection of the optimal data source for the cultural heritage threat analysis of historic sites was carried out. The analyses were conducted for three scenarios, using ArcGIS Pro 2.7 software. A series of maps were thus prepared to show the threats to specific historic sites for various global sea level rise scenarios. Even with the slightest rise in sea level, monuments could be permanently lost. The authors point out that a lack of action to stop climate change could result not only in economic but also cultural losses. [ABSTRACT FROM AUTHOR]

Global climate change scenarios predict that lake water temperatures will increase up to 4 °C and extreme weather events, such as heat waves and large temperature fluctuations, will occur more frequently. Such changes may result in the increase of aquatic litter decomposition and on shifts in diversity and structure of bacteria communities in this period. We designed a two-month mesocosm experiment to explore how constant (+4 °C than ambient temperature) and variable (randomly +0~8 °C than ambient temperature) warming treatment will affect the submerged macrophyte litter decomposition process. Our data suggests that warming treatments may accelerate the decomposition of submerged macrophyte litter in shallow lake ecosystems, and increase the diversity of decomposition-related bacteria with community composition changed the relative abundance of Proteobacteria, especially members of Alphaproteobacteria increased while that of Firmicutes (mainly Bacillus) decreased. [ABSTRACT FROM AUTHOR]

Fluvial flooding in Canada is often snowmelt-driven, thus occurs mostly in spring, and has caused billions of dollars in damage in the past decade alone. In a warmer climate, increasing rainfall and changing snowmelt rates could lead to significant shifts in flood-generating mechanisms. Here, projected changes to flood-generating mechanisms in terms of the relative contribution of snowmelt and rainfall are assessed across Canada, based on an ensemble of transient climate change simulations performed using a state-of-the-art regional climate model. Changes to flood-generating mechanisms are assessed for both a late 21st century, high warming (i.e., Representative Concentration Pathway 8.5) scenario, and in a 2 °C global warming context. Under 2 °C of global warming, the relative contribution of snowmelt and rainfall to streamflow peaks is projected to remain close to that of the current climate, despite slightly increased rainfall contribution. In contrast, a high warming scenario leads to widespread increases in rainfall contribution and the emergence of hotspots of change in currently snowmelt-dominated regions across Canada. In addition, several regions in southern Canada would be projected to become rainfall dominated. These contrasting projections highlight the importance of climate change mitigation, as remaining below the 2 °C global warming threshold can avoid large changes over most regions, implying a low likelihood that expensive flood adaptation measures would be necessary. [ABSTRACT FROM AUTHOR]

This study introduces a hydro-climatic extremes assessment framework that combines the latest climate simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6) HighResMIP with the Soil and Water Assessment (SWAT) model, and examines the influence of the different climate model resolutions. Sixty-six hydrological and environmental flow indicators from the Indicators of Hydrologic Alteration (IHA) were computed to assess future extreme flows in the Kelantan River Basin (KRB), Malaysia, which is particularly vulnerable to flooding. Results show that the annual precipitation, streamflow, maximum and minimum temperatures are projected to increase by 6.9%, 9.9%, 0.8 °C and 0.9 °C, respectively, by the 2021–2050 period relative to the 1985–2014 baseline. Monthly precipitation and streamflow are projected to increase especially for the Southwest Monsoon (June–September) and the early phase of the Northeast Monsoon (December) periods. The magnitudes of the 1-, 3-, 7-, 30- and 90-day minima flows are projected to increase by 7.2% to 8.2% and the maxima flows by 10.4% to 28.4%, respectively. Lastly, changes in future hydro-climatic extremes are frequently quite different between the high-resolution and low-resolution models, e.g., the high-resolution models projected an increase of 11.8% in mean monthly flow in November-December-January compared to 3.2% for the low-resolution models. [ABSTRACT FROM AUTHOR]

Tropical cyclones (TCs) play an important role in the precipitation of tropical oceans and islands. The temporal and spatial characteristics of precipitation have become more complex in recent years with climate change. Global warming tips the original water and energy balance in oceans and atmosphere, giving rise to extreme precipitation events. In this study, the monthly precipitation ratio method, spatial analysis, and correlation analysis were employed to detect variations in precipitation in the South China Sea (SCS). The results showed that the contribution of TCs was 5.9% to 10.1% in the rainy season and 7.9% to 16.8% in the dry season. The seven islands have the same annual variations in the precipitation contributed by TCs. An 800 km radius of interest was better for representing the contribution of TC-derived precipitation than a 500 km conventional radius around reclaimed islands in the SCS. Four track patterns of TCs were defined. The order according to the primary pattern of contribution was I (26–85.3%) > IV (12.8–29.8%) > III (4.3–29%) > II (11.5–24%). The average distance between islands and TCs was 1163 and 712 km in the rainy and dry seasons, respectively. The average contribution was larger in La Niña than in El Niño periods. These results could be beneficial for managing rainwater resources, especially the TC-induced precipitation in the reclaimed islands. [ABSTRACT FROM AUTHOR]

Characterized by increasing surface air temperature, global warming has altered the hydrological cycle at global and regional scales. In order to adapt water resources management under the context of global warming, attribution analysis on regional differentiation of water resources in the Yangtze River basin (YRB) was conducted in this study. Meteoro-hydrological variations across the basin were examined for the period 1960–2013, and then a statistic-based method was applied in quantifying the contributions of climate variability and human activities on annual runoff variations in different tributary sub-basins in the YRB. Our observation indicates that both the annual increasing rate and the inter-annual fluctuations of temperature in China and in the YRB were higher than that of the global average since the turn of the century. Climate change analysis indicates that the YRB experienced a hot-wet period during 1994–2002 and a hot-dry period during 2003–2013, since the step change of temperature in 1993. Contributions of climate change and human activities on runoff variations varied spatially in the basin. With reference to the baseline period of 1960–1993, the contribution of climate change played a dominant role in most regions of the basin, especially in those upstream sub-basins. The effect of human activities in the basin was quite complicated, not only its regional differentiation, but also its contribution were opposite during the hot-wet period and the hot-dry period in some sub-basins. The result of this study is helpful in understanding the impacts of climate change and human activities on water resources variation in both temporal and spatial scales. [ABSTRACT FROM AUTHOR]

Climate change influences the changes in drought features. This study assesses the changes in severe drought characteristics over the Asian monsoon region responding to 1.5 and 2.0 °C of global average temperature increases above preindustrial levels. Based on the selected 5 global climate models, the drought characteristics are analyzed according to different regional climate zones using the standardized precipitation index. Under global warming, the severity and frequency of severe drought (i.e., SPI <−1.5) are modulated by the changes in seasonal and regional precipitation features regardless of the region. Due to the different regional change trends, global warming is likely to aggravate (or alleviate) severe drought in warm (or dry/cold) climate zones. For seasonal analysis, the ranges of changes in drought severity (and frequency) are −11.5%~6.1% (and −57.1%~23.2%) under 1.5 and 2.0 °C of warming compared to reference condition. The significant decreases in drought frequency are indicated in all climate zones due to the increasing precipitation tendency. In general, drought features under global warming closely tend to be affected by the changes in the amount of precipitation as well as the changes in dry spell length. As the warming enhanced, the spatial variation of drought severity will be increased across climate zones, which can lead to increased water stress over Asia. This study demonstrates that precipitation characteristic changes can explicitly modulate severe regional drought features. [ABSTRACT FROM AUTHOR]

The relationship between climate change and water is an obvious and key issue within the United Nations Sustainable Development Goals. This study aims to investigate the social representation created around this relationship in three different territorial contexts in order to evaluate the influence of the territory on the perception of the risk of climate change and its relationship with water. By means of a questionnaire completed by 1709 university students, the climatic literacy of the individual was evaluated in order to relate it to other dimensions on the relationship between climate change and water (information, training previous on climate change and pro-environmental attitudes) in their different dimensions in three different territorial contexts. Three hypotheses have been tested: (1) The denial of the CC is significantly associated with a representation that belittles the consequences of global warming and other extreme phenomena. (2) Territorial contexts with high average rainfall levels and low average annual temperatures tend to minimize the social representation of water risks associated with the CC. (3) There is significant interaction between the socio-cultural context and social representations on the causes, consequences and solutions to the problems of CC and water. The first two hypotheses have been rejected, while the third has been accepted. The research results show high climate literacy in the samples of selected university students. It is noted that students recognize a close relationship between the problem of water and the climate crisis. Likewise, they identify different types of causes, consequences, physical processes and solutions. Different climatological contexts do not show significant differences in the social representations that students show about climate change, while socio-educational variables such as available scientific information, or ideology orientation do show significant differences. [ABSTRACT FROM AUTHOR]

Based on the 1965–2017 climate data of 18 meteorological stations in the Songliao Plain maize belt, the Coupled Model Intercomparision Project (CMIP5) data, and the 1998–2017 maize yield data, the drought change characteristics in the study area were analyzed by using the standardized precipitation evapotranspiration index (SPEI) and the Mann–Kendall mutation test; furthermore, the relationship between meteorological factors, drought index, and maize climate yield was determined. Finally, the maize climate yields under 1.5 °C and 2.0 °C global warming scenarios were predicted. The results revealed that: (1) from 1965 to 2017, the study area experienced increasing temperature, decreasing precipitation, and intensifying drought trends; (2) the yield of the study area showed a downward trend from 1998 to 2017. Furthermore, the climate yield was negatively correlated with temperature, positively correlated with precipitation, and positively correlated with SPEI-1 and SPEI-3; and (3) under the 1.5 °C and the 2.0 °C global warming scenarios, the temperature and the precipitation increased in the maize growing season. Furthermore, under the studied global warming scenarios, the yield changes predicted by multiple regression were −7.7% and −15.9%, respectively, and the yield changes predicted by one-variable regression were −12.2% and −21.8%, respectively. [ABSTRACT FROM AUTHOR]

Climate change has unchained several natural extreme phenomena, including a major frequency and intensity of flooding episodes. From these, the ones of greatest importance are those which endanger human settlements as well as socioeconomic activities. This is the case of Tamuín city, settled in the shore of Tampaón River, in Mexico. In this work, we performed a detailed numerical modelling of the hydrodynamics of the zone, considering in situ topographic and bathymetric data as well as hydrodynamic parameters. Severe rainfall scenarios were simulated in order to determine the zones which are prone to flooding, as well as the potential periods of time between the beginning of the rainfall up to the flooding, considering the potential effects of climate change in the precipitation rate. The outcome of this research will help local governments undertake preventive actions to reinforce the identified risky zones, thus providing an adequate protection of rural and urban zones, as well as their inhabitants and their economical activities from current and future floods, considering potential climate change effects. [ABSTRACT FROM AUTHOR]

The Bialowieza Primeval Forest (BF) is one of the well-known forests in Central Europe. The most common tree species in BF was Norway spruce (Picea abies (L.) H. Karst), comprising 26%. However, a mass dieback of spruce has occurred during recent years. The spruce dieback in Bialowieza Forest is directly caused by the spruce bark beetle. However, the mass appearance of this pest can be a consequence of global warming and drought. Changes in air temperature were presented and drought indices were calculated as follows: standardized precipitation index, Palmer drought severity index, climatic water balance and soil water storage deficit. The warming of the climate of Bialowieza from 1950 to 2015 is comparable to that observed throughout central Europe. The temperature increased by 1.27 °C. The occurrence of drought from 1950 to 1966 and from 1985 to 2015 had a similar frequency. From 1963 to 1966, the volume of removed deadwood from the managed part of Bialowieza Forest was 27 thousand m3 but from 2012 to 2016, the volume was more than one million m3. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including climate change, lake warming and land use.

The potential influence of natural variations in a climate system on global warming can change the hydrological cycle and threaten current strategies of water management. A simulation-based linear fractional programming (SLFP) model, which integrates a runoff simulation model (RSM) into a linear fractional programming (LFP) framework, is developed for optimal water resource planning. The SLFP model has multiple objectives such as benefit maximization and water supply minimization, balancing water conflicts among various water demand sectors, and addressing complexities of water resource allocation system. Lingo and Excel programming solutions were used to solve the model. Water resources in the main stream basin of the Songhua River are allocated for 4 water demand sectors in 8 regions during two planning periods under different scenarios. Results show that the increase or decrease of water supply to the domestic sector is related to the change in population density at different regions in different target years. In 2030, the water allocation in the industrial sector decreased by 1.03–3.52% compared with that in 2020, while the water allocation in the environmental sector increased by 0.12–1.29%. Agricultural water supply accounts for 54.79–77.68% of total water supply in different regions. These changes in water resource allocation for various sectors were affected by different scenarios in 2020; however, water resource allocation for each sector was relatively stable under different scenarios in 2030. These results suggest that the developed SLFP model can help to improve the adjustment of water use structure and water utilization efficiency. [ABSTRACT FROM AUTHOR]

The study evaluated the effect of environmental conditions and morphometric parameters on lake water temperature changes. The analysis was carried out on the basis of 14 lakes located in northern Poland. The assessment was based on the daily water and air temperatures from 1972 to 2016. It took into account the location of lakes (latitude, longitude, altitude) morphometric parameters (surface area, maximum and mean depth, volume), hydrological processes (rate of water exchange, course of ice phenomena), and trophic status (water transparency) as factors that can modify lake water temperature changes. Direction and rate of air and water temperature changes were analysed by means of Mann–Kendall’s and Sen’s tests. Cluster analysis (CA) was applied to group lakes characterised by similar water temperature changes. The effect of climatic and non-climatic parameters on a lake’s water temperature was assessed on the basis of principal component analysis (PCA). Water temperatures in the lakes in the years 1972–2016 were characterised by a higher rate of increase of 0.43 °C·dec−1 than the air temperature decrease of 0.34 °C·dec−1. The analysis showed a faster rate of heating of waters in western Poland. This can be explained by shorter duration of ice cover. Moreover, the changes of water temperature were affected by other factors, including the location of the lakes, their morphometric parameters, wind speed, water transparency and water exchange time. [ABSTRACT FROM AUTHOR]

We present a detailed study of the snowpack trends in the Rocky Mountain National Park (RMNP) using snow telemetry and snow course data at a monthly resolution. We examine the past 35 years (1981 to 2016) to explore monthly patterns over 36 locations and used some additional data to help interpret the changes. The analysis is at a finer spatial and temporal scale than previous studies that focused more on aggregate- or regional-scale changes. The trends in the first of the month’s snow water equivalent (SWE) varied more than the change in the monthly SWE, monthly precipitation or mean temperature. There was greater variability in SWE trends on the west side of the study area, and on average the declines in the west were greater. At higher elevations, there was more of a decline in the SWE. Changes in the climate were much less in winter than in summer. Per decade, the average decline in the winter precipitation was 4 mm and temperatures warmed by 0.29 °C, while the summer precipitation declined by 9 mm and temperatures rose by 0.66 °C. In general, November and March became warmer and drier, yielding a decline of the SWE on December 1st and April 1st, while December through February and May became wetter. February and May became cooler. [ABSTRACT FROM AUTHOR]

In 1983, the North Cascade Glacier Climate Project (NCGCP) began the annual monitoring of the mass balance on 10 glaciers throughout the range, in order to identify their response to climate change. Annual mass balance (Ba) measurements have continued on seven original glaciers, with an additional two glaciers being added in 1990. The measurements were discontinued on two glaciers that had disappeared and one was that had separated into several sections. This comparatively long record from nine glaciers in one region, using the same methods, offers some useful comparative data in order to place the impact of the regional climate warmth of 2015 in perspective. The mean annual balance of the NCGCP glaciers is reported to the World Glacier Monitoring Service (WGMS), with two glaciers, Columbia and Rainbow Glacier, being reference glaciers. The mean Ba of the NCGCP glaciers from 1984 to 2015, was −0.54 m w.e.a−1 (water equivalent per year), ranging from −0.44 to −0.67 m w.e.a−1 for individual glaciers. In 2015, the mean Ba of nine North Cascade glaciers was −3.10 m w.e., the most negative result in the 32-year record. The correlation coefficient of Ba was above 0.80 between all North Cascade glaciers, indicating that the response was regional and not controlled by local factors. The probability of achieving the observed 2015 Ba of −3.10 is 0.34%. [ABSTRACT FROM AUTHOR]