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Although Integrated Water Resources Management (IWRM) is widely accepted as the state-of-the-art rational model for improving water governance, its evaluations under climate change at national and global scales indicate that progress made in water security and ecosystem preservation is slow. The paper identifies the relationship between Humans and Nature as the main reason for that and generates a novel social component to improve Water Resources Management (WRM) following three pillars: (1) A historical review over the past 20,000 years indicating that WRM depends on the interplay between Humans and Nature. This is in constant change over time, and depending on socio-economic and climate conditions, it oscillates between two opposites: conflict and cooperation. Three clusters have been identified, showing a different timeline pattern of dominance: (a) Nature dominating Humans (Naturalistic), (b) Nature–Humans in cooperation and competition (Dualistic), and (c) Humans dominating Nature (Anthropocentric). (2) Clarification of why a WRM model can improve water security through the Governance–Policy–Science Nexus. (3) Suggestion of a novel WRM model based on conflict identification (eristic component) and dialectical conflict resolution. Two types of conflicts have been distinguished: (a) Human vs. Human and (b) Human vs. Nature when the laws of nature are not respected. The dialectical tool operates by exchanging rational arguments to unify opposite objectives for harmonizing Humans with Natural laws. A case study of flood mitigation in Crete Island illustrates the Eristic–Dialectical methodology. [ABSTRACT FROM AUTHOR]

This paper introduces a climatic multi-hazard risk assessment for Greece, as the first-ever attempt to enhance scientific knowledge for the identification and definition of hazards, a critical element of risk-informed decision making. Building on an extensively validated climate database with a very high spatial resolution (5 × 5 km2), a detailed assessment of key climatic hazards is performed that allows for: (a) the analysis of hazard dynamics and their evolution due to climate change and (b) direct comparisons and spatial prioritization across Greece. The high geographical complexity of Greece requires that a large number of diverse hazards (heatwaves—TX, cold spells—TN, torrential rainfall—RR, snowstorms, and windstorms), need to be considered in order to correctly capture the country's susceptibility to climate extremes. The current key findings include the dominance of cold-temperature extremes in mountainous regions and warm extremes over the coasts and plains. Extreme rainfall has been observed in the eastern mainland coasts and windstorms over Crete and the Aegean and Ionian Seas. Projections of the near future reveal more warm extremes in northern areas becoming more dominant all over the country by the end of the century. [ABSTRACT FROM AUTHOR]

Wind parks are widely propagated as 'a solution' or in many ways as 'a gift' to mitigate climate change and instigate economic growth, which should be 'rolled inside community gates' through new legislation enabling investments. This paper dissects two experiences of wind energy development in Crete, Greece and Oaxaca, Mexico, exploring key commonalities and differences. It demonstrates that land/green grabbing, but more specifically 'accumulation by wind energy', is taking place in both regions. The specific processes and outcomes of 'accumulation by wind energy' differ according to the socio-political and ecological context of each case. There are, however, various similarities in logics, methods and strategies facilitating accumulation by wind energy that reveal defining features and similar outcomes. Wind energy development in Crete and Oaxaca is continuing the existing trajectory of energy extraction companies, resulting in an intensification of existing income-inequality, ecological degradation and social conflict, whilst spreading coercive cultural change. Based on these cases and critical (wind park) literature, we argue, that in actuality wind energy development represents a 'Trojan horse' for capitalism's ongoing growth intensifying socio-ecological crisis through 'accumulation by wind energy'. Wind parks serve as 'Trojan horses' for, amongst others, corporate land grabbing and temporarily mediating capitalism's key contradictions. [ABSTRACT FROM AUTHOR]

This paper aims to study wet-cold compound events (WCCEs) over Greece for the wet and cold season November-April. WCCEs are divided in two different compound events (TX-RR) and (TN-RR) and two different approaches using fixed (RR over 20 mm/day and Temperature under 0 °C) and percentile (RR over 95th and Temperature under 5th) thresholds. Observational data from the Hellenic National Meteorology Service (HNMS) and simulation data from reanalysis and EUROCORDEX models were used in the study for the historical period 1980-2004. Simulation datasets from projection models were employed for the near future period (2025-2049) to study the impact of climate change on the occurrence of WCCEs under RCP 4.5 and 8.5 scenarios. Following data processing and validation of the models, the potential changes in the distribution of WCCEs in the future were investigated based the projected and historical simulations. WCCEs determined by fixed thresholds were mostly found over high altitudes with a future tendency to reduce particularly under RCP 8.5. On the other hand, WCCEs obtained with percentile thresholds, were distributed mostly in Eastern Greece and Crete while their changes differed significantly among models. [ABSTRACT FROM AUTHOR]

The Mediterranean Basin is severely impacted by anthropogenic changes affecting both natural ecosystems and human livelihoods. The region is highly vulnerable to natural hazards, with floods being considered the most important, due both to their frequency and impacts. Koiliaris watershed (northwest of Crete Island, Greece) represents a relevant case study as past land-use changes via deforestation and intense cultivation practices induce soil organic matter losses, making soils susceptible to water erosion and desertification. The restoration of native riparian forests has been identified as the most effective nature-based solution (NBS) for the area. Through modeling, our study assessed the effectiveness of this NBS in addressing flood risk and erosion while providing additional ecosystem services (carbon sequestration and biodiversity conservation). A cost–benefit analysis has been then implemented to also investigate the sustainability of the investment from an economic point of view. Our results show the NBS would be successful in ensuring a better flow of targeted ecosystem services compared to the business-as-usual conditions. The associated investment would result in economic sustainability and associated costs would be paid back in five years. Though site-specific, our study provides lessons learned for dealing with future land-restoration challenges in the Mediterranean to cope with climate change-related challenges. [ABSTRACT FROM AUTHOR]

Agricultural systems are constantly stressed due to higher demands for products. Consequently, water resources consumed on irrigation are increased. In combination with the climatic change, those are major obstacles to maintaining sustainable development, especially in a semi-arid land. This paper presents an end-to-end Machine Learning framework for predicting the potential profit from olive farms. The objective is to estimate the optimal economic gain while preserving water resources on irrigation by considering various related factors such as climatic conditions, crop management practices, soil characteristics, and crop yield. The case study focuses on olive tree farms located on the Hellenic Island of Crete. Real data from the farms and the weather in the area will be used. The target is to build a framework that will preprocess input data, compare the results among a group of Machine Learning algorithms and propose the best-predicted value of economic profit. Various aspects during this process will be thoroughly examined such as the bias-variance tradeoff and the problem of overfitting, data transforms, feature engineering and selection, ensemble methods as well as pursuing optimal resampling towards better model accuracy. Results indicated that through data preprocessing and resampling, Machine Learning algorithms performance is enhanced. Ultimately, prediction accuracy and reliability are greatly improved compared to algorithms' performances without the framework's operation. [ABSTRACT FROM AUTHOR]

High mountain zones in the Mediterranean area are considered more vulnerable in comparison to lower altitudes zones. Lefka Ori massif, a global biodiversity hotspot on the island of Crete is part of the Global Observation Research Initiative in Alpine Environments (GLORIA) monitoring network. The paper examines species and vegetation changes with respect to climate and altitude over a seven-year period (2001–2008) at a range of spatial scales (10 m Summit Area Section-SAS, 5 m SAS, 1 m2) using the GLORIA protocol in a re-survey of four mountain summits (1664 m–2339 m). The absolute species loss between 2001–2008 was 4, among which were 2 endemics. At the scale of individual summits, the highest changes were recorded at the lower summits with absolute species loss 4 in both cases. Paired t-tests for the total species richness at 1 m2 between 2001–2008, showed no significant differences. No significant differences were found at the individual summit level neither at the 5 m SAS or the 10 m SAS. Time series analysis reveals that soil mean annual temperature is increasing at all summits. Linear regressions with the climatic variables show a positive effect on species richness at the 5 m and 10 m SAS as well as species changes at the 5 m SAS. In particular, June mean temperature has the highest predictive power for species changes at the 5 m SAS. Recorded changes in species richness point more towards fluctuations within a plant community's normal range, although there seem to be more significant diversity changes in higher summits related to aspects. Our work provides additional evidence to assess the effects of climate change on plant diversity in Mediterranean mountains and particularly those of islands which remain understudied. [ABSTRACT FROM AUTHOR]

This study investigates the variability and trends of the mean annual and seasonal surface air temperature in southern Greece, namely in Crete and in the islands of the southern Aegean Sea. The climatic data used are the mean monthly homogenized air temperature values of seven meteorological stations of the Hellenic Meteorological Service, for the period 1960–2004. A Bayesian trend analysis is performed by fitting alternative stochastic‐trend models based on the Log‐normal, the Normal, the Generalized Extreme Value and the Gumbel distributions. Posterior simulations results based on the best fitting model reveal the locations and time‐periods with the strongest and the weakest interannual trends for both mean and variance. Furthermore, a model comparison experiment based on Bayes Factors compares the above stochastic‐trend models with the corresponding ones with no‐time trends. The results are very significant since they reveal the locations and the seasons where interannual trends for both mean and variance have real grounds. [ABSTRACT FROM AUTHOR]

The thermal environment in outdoor public spaces and their level of use are strongly connected. The design of outdoor spaces, especially in urban areas, is very critical in Southern Europe due to their extended use during summertime where the urban heat island phenomenon deteriorates the microclimatic conditions. In this paper the main outcomes of outdoor spaces field surveys are presented, which were carried out in four different urban open spaces in Crete. On site measurements were implemented and a questionnaire was used in order to estimate the thermal comfort of visitors. Thermal indices like Predicted Mean Vote, Physiologically Equivalent Temperature, Standard Effective Temperature, Wet Bulb Globe Temperature are used to evaluate the features of urban microclimate and then are being compared in order to find the most suitable for the Mediterranean microclimate. This suggests another way of approach to the researcher and provides essential tools to the designer. [ABSTRACT FROM AUTHOR]

Geographically isolated insular species face energetic restrictions and commonly evolve adaptations that distinguish them from their mainland ancestors. During the Pleistocene, several Mediterranean islands were inhabited by now extinct Hippopotamidae. They underwent diverse changes in locomotion, dentition and body size. Based on these differences, it is supposed that they occupied different ecological niches depending on their respective faunal complexes and available resources. In this paper, we assess the paleoecology of dwarfed hippopotami from Crete, Malta, Sicily and Cyprus using a novel dental multiproxy approach. We applied dental topography analysis (SAGA-GIS) to measure the mean slope of the dental occlusal surface, mirroring dietary adaptations, as well as 3D surface texture analysis (3DST) to quantify the surface of occlusal wear facets, which correlate with dietary abrasiveness. Low slope values were found in the larger, more hypsodont hippopotami, whilst the smaller Phanourios minor displayed the highest occlusal relief with large compression basins. Since Hippopotamus pentlandi exhibited lower mean slope values than the larger, more hypsodont Hippopotamus amphibius , we conclude that lower occlusal reliefs reflect adaptations to lower diet quality and arid environments, which are characteristic of freshwater-limited island habitats. The 3DST analysis revealed distinct ecological niches for the investigated insular hippos. Hippopotamus creutzburgi exhibited enamel surface textures analogous to those of Hippopotamus amphibius , a fresh grass grazer, thus confirming a semiaquatic lifestyle at the upland lake at Katharo, Crete. Hippopotamus pentlandi was bound to a similar niche to the extant form, probably due to the mainland character of its fauna, but experienced more dust intake. Hippopotamus melitensis had to cope with high ingestion of abrasives, seemingly on account of a more generalistic diet in its resource-limited and small habitat. Results point to either Phanourios minor broadening its dietary niche in its almost competition-free habitat, or suggest a dietary shift following a climatic change. The adopted multiproxy approach proved to be useful in identifying dental adaptations and individual foraging strategies linked to energetically restricted habitats, and therefore contributes to a better understanding of basic evolutionary and ecological principles. • Novel multiproxy approach reveals dietary traits in Pleistocene dwarf hippopotami. • SAGA-GIS reveals dental adaptations, 3DST analysis individual forage behaviour. • Now extinct dwarfed island hippopotami occupied distinct ecological niches. • Lower occlusal reliefs evolved in dwarfed Hippopotamidae facing limited resources. • 3DST analysis reveals specialisation, generalism or shifts in diet of dwarfed hippos. [ABSTRACT FROM AUTHOR]

Within the framework of disaster risk management, this article proposes an interdisciplinary method for the analysis of multiple natural hazards, including climate change's influences, in the context of cultural heritage. A taxonomy of natural hazards applicable to cultural heritage was developed based on the existing theoretical and conceptual frameworks. Sudden-onset hazards, such as earthquakes and floods, and slow-onset hazards, such as wetting–drying cycles and biological contamination, were incorporated into the hazard assessment procedure. Future alteration of conditions due to climate change, such as change in heat waves' duration, was also taken into account. The proposed hazard assessment framework was applied to the case of the Historic Centre of Rethymno, a city on the northern coast of the island of Crete in Greece, to identify, analyze, and prioritize the hazards that have the potential to cause damage to the center's historic structures. The assessment procedure includes climate model projections, GIS spatial modeling and mapping, and finally a hazard analysis matrix to enable the sharing of a better understanding of multiple hazards with the stakeholders. The results can facilitate decision making by providing the vulnerability and risk analysis with the nature and spatial distribution of the significant hazards within the study area and its setting. [ABSTRACT FROM AUTHOR]

Based on the predictions of General Circulation Models, significant reduction of precipitation in Mediterranean areas is a possible scenario. Hence, better understanding of the spatial and temporal precipitation patterns is necessary in order to quantify desertification risks and design suitable mitigation measures. This study uses monthly precipitation measurements from a sparse network of 54 monitoring stations on the Mediterranean island of Crete (Greece). The study period extends from 1948 to 2012. The data reveal strong correlations between the western and eastern parts of the island. However, the average annual precipitation in the West is about 450 mm higher than that in the East. We construct a spatial model of average annual precipitation in Crete. The model involves a topographic trend and residuals with anisotropic spatial correlations which are fitted with a recently developed variogram function. We use regression kriging to generate annual precipitation maps and to identify locations of high estimation uncertainty. To our knowledge, this is the most detailed spatial analysis of precipitation in Crete to date. We present the analysis in detail for the year 1971. The trend accounts for ≈ 74% of the total variance. The highest precipitation estimate is 2331 mm in the West and 1781 mm in the East. The highest relative estimation uncertainty (≈ 20%) is observed along the southeastern coastline of the island, where the lowest values of annual precipitation are observed. This region includes one of the major agricultural areas of the island. The same overall patterns are found for other years in the study. Finally, we find no statistical evidence for a decrease in the global (over the entire island) annual precipitation during the study period. [ABSTRACT FROM AUTHOR]

Recent climate change studies for the Mediterranean region have projected the near future temperature and precipitation trends. The increasing water demands for human consumption and agricultural purposes, as well as the potential overexploitation of the groundwater resources, in combination with the climatic projections are expected to affect the groundwater resources of the Mediterranean hydrological basins. This work focuses on the Viannos alluvial basin at the island of Crete, Greece. It considers primarily the increasing water demands for irrigation in the area of interest and the projected precipitation trend in the next five hydrological years for the island of Crete. The groundwater system is simulated based on the current hydrological/hydrogeological conditions of the basin and based on anticipated hydrological events. Scenarios concerning future precipitation trends and pumping schemes at existing wells are examined to assess the near-future stresses on the basin groundwater resources. Groundwater flow modeling is performed using the Visual Modflow software. Based on the study of different scenarios modeling results show that the aquifer is primarily affected during the dry period of the hydrological year. However, sufficiently replenishment is observed during the wet period as the highest water table drop is 0.65 m at the end of the 5 years modelling period. Therefore, the aquifer is not expected to face serious problems in the near future from the increased irrigation demands and from the short-term projected precipitation trends. Simulations for 10 and 20-year periods following the precipitation projections and the specified pumping schemes also show that the aquifer resources are not expected to be significantly affected. [ABSTRACT FROM AUTHOR]

A soil survey and mapping program financed by the municipality of Gazi located on the north–central part of Crete was carried out. The studied area is characterized by a moist meso-Mediterranean climate and different degrees of land degradation from human activities. Surface soil horizons are eroded, resulting in fertility decline for olive trees, the dominant crop. According to the U.S. Department of Agriculture classification, the soils at higher altitudes are classified as Entisolsxerorthentsand those at lower altitudes as E.xerofluvents.Using a geographical information system (GIS), all spatial data from the soil survey were organized to facilitate its storage, management, and analysis. Based on topographic–geological maps and aerial photographs, other derivative data layers were calculated. Sampling points were determined using GIS. This information, and all results pertaining to the sample, was entered into a graphical database, designed to store all relevant data for each point. Data layers describing the spatial distribution of key parameters such as soil texture, pH, CaCO3, and nutrient status were produced using geostatistical methods. Soil classification and the evaluation of soil suitability for various activities were greatly facilitated by visualization of the data as various thematic maps. Our study demonstrates the ability of GIS as an administrative tool that can assist farmers in improving farming practices. [ABSTRACT FROM AUTHOR]

The aim of this study is to develop a relationship between rainfall and surface water (runoff) in South Crete, Greece. This application was carried out on five sub-basins in the Messara valley, with a total surface of 1125 km2. Three factors were taken into account: the climate regime including precipitation and air temperature, the geological nature of the ground and the surface area of the basin. The development of the rainfall-discharge model consisted of three steps. Firstly, the actual evapotranspiration ( Er) was computed. Secondly, the storage capacity of each hydrogeological unit in every catchment area was geologically estimated and, lastly, the rainfall-runoff model was developed using the water balance equation and the above mentioned relationship of Er. The amount of variance in runoff between the sub-basins explained by those three factors was 92%. Decreases in mean annual precipitation by 17 and 15% for east and west Messara, respectively, predicted by the regional climate model REMO resulted in even more drastic mean runoff reductions by 29 and 32% at the respective sides of the valley. Furthermore, the coefficient of variation of runoff increased by more than 15% in the east side of the valley but dropped by only 1.5% in the west. The proposed rainfall-discharge relationship is a useful tool for hydrological management and evaluation of water resources under the present-day and future climate conditions in Messara valley in Crete. Copyright © 2011 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Climate change is expected to have a significant impact on the hydrologic cycle, creating changes in freshwater resources. The Intergovernmental Panel on Climate Change (IPCC) predicts that, as a result, floods and prolonged droughts will take place at increasingly frequent periods. The Mediterranean has been described as one of the main climate change 'hot-spots', with recent simulations showing a collective picture of substantial drying and warming. This effect appears more pronounced during warm periods, when the seasonal decrease of precipitation can exceed control climatology by 25-30%. Despite the decreasing annual rainfall trend, an increase in the amount and intensity of wintertime rainfall is evident. However, the scientific question on the quantitative impact of these signals to small scale coastal watersheds and Mediterranean islands has not been answered. The state-of-the-art Ensembles dataset was employed to assess the impact of the changing climate on the water availability of the island of Crete at basin scale. Here, the Ensembles precipitation and temperature data is used as input for a rainfall-runoff model previous calibrated for the whole island with the principle of regionalization. Data analysis for the period 1970-2100 reveals an overall decreasing precipitation trend which, combined with a temperature rise, leads to substantial reduction of water availability. Quantitative results of hydrological change provide the data required to improve knowledge and adaptation policy to water shortages. [ABSTRACT FROM AUTHOR]

This study explores the past, present and future ecological changes in the highest Mediterranean temporary pond (Omalos pond) in western Crete, Greece. Data from downcore pollen analysis (including pollen and spores from both aquatic vegetation, and terrestrial herbaceous, arboreal and shrub vegetation), modern vegetation monitoring and existing climate scenarios have been combined to provide a picture of the ecological changes in the pond over the last 13,600 years. Downcore pollen analysis throughout the last 13,600 years indicated the presence of species typical of Mediterranean Temporary Pond (MTP) habitats and suggested relatively drier conditions towards the present. The low number of non-native, cultivated species (such as herbaceous Trifolium and Plantago species) observed over this period suggested relatively low impact from crop agriculture, despite the increasing grazing pressure in the area. In the absence of independent proxies, we cannot reliably distinguish between natural and human-induced changes. The presence of aquatic Isoetes in the palaeo-record indicates the existence of an ephemeral pond in the area as early as the beginning of the Holocene suggesting resilience of the ecosystem over time. However, the degraded state of pollen in depths over 55 cm (i.e. 3600 year BP) increases the uncertainty of the interpretation. Currently, the pond holds 76 plant species belonging to 25 families. Therophytes and chamaephytes were the most frequent, suggesting a typical ephemeral habitat life form spectrum. Species richness was found to increase during spring surveys whereas the highest turnover was observed between summer surveys of consecutive years. Cluster analysis demonstrated a distinct zonation in four vegetation belts from the periphery to the centre of the pond which is typical of these environments. Modelling, based on two IPPC scenarios (A2 and B2), predicted relatively low climate change impacts on the pond’s hydroperiod for the next 100 years (i.e. a decrease of 16 and 24 days, respectively). This reduction in the hydroperiod of the pond will have an effect on the physiognomy and spatial extent of vegetation, particularly for the transitional belts between the core and its outer area, while it will exert more pressure on the pond as a water resource for sheep in the region. However, cumulative effects and complex interactions of climate-driven environmental changes and other anthropogenic disturbances might act synergistically to accelerate impacts in the future. [ABSTRACT FROM AUTHOR]

The coastal ocean is one of the most important environments on our planet, home to some of the most bio-diverse and productive ecosystems and providing key input to the livelihood of the majority of human society. It is also a highly dynamic and sensitive environment, particularly susceptible to damage from anthropogenic influences such as pollution and over-exploitation as well as the effects of climate change. These have the added potential to exacerbate other anthropogenic effects and the recent change in sea temperature can be considered as the most pervasive and severe cause of impact in coastal ecosystems worldwide. In addition to open ocean measurements, satellite observations of sea surface temperature (SST) have the potential to provide accurate synoptic coverage of this essential climate variable for the near-shore coastal ocean. However, this potential has not been fully realized, mainly because of a lack of reliable in situ validation data, and the contamination of near-shore measurements by the land. The underwater biotechnological park of Crete (UBPC) has been taking near surface temperature readings autonomously since 2014. Therefore, this study investigated the potential for this infrastructure to be used to validate SST measurements of the near-shore coastal ocean. A comparison between in situ data and Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua and Terra SST data is presented for a four year (2014–2018) in situ time series recorded from the UBPC. For matchups between in situ and satellite SST data, only nighttime in situ extrapolated to the sea surface (SSTskin) data within ±1 h from the satellite's overpass are selected and averaged. A close correlation between the in situ data and the MODIS SST was found (squared Pearson correlation coefficient-r2 > 0.9689, mean absolute error-Δ < 0.51 both for Aqua and Terra products). Moreover, close correlation was found between the satellite data and their adjacent satellite pixel's data further from the shore (r2 > 0.9945, Δ < 0.23 for both Aqua and Terra products, daytime and nighttime satellite SST). However, there was also a consistent positive systematic difference in the satellite against satellite mean biases indicating a thermal adjacency effect from the land (e.g., mean bias between daytime Aqua satellite SST from the UBPC cell minus the respective adjacent cell's data is δ = 0.02). Nevertheless, if improvements are made in the in situ sensors and their calibration and uncertainty evaluation, these initial results indicate that near-shore autonomous coastal underwater temperature arrays, such as the one at UBPC, could in the future provide valuable in situ data for the validation of satellite coastal SST measurements. [ABSTRACT FROM AUTHOR]

Climate change will have a greater impact on the severity of flash floods, since precipitation intensity is expected to increase, even in areas where a reduction of precipitation is possible. This change in climate is expected to increase flood wave speed and its flood wave area extent. A case study of a small basin in the island of Crete was conducted to examine this effect, following the calibration and validation of the flow hydrograph of a flash flood event, in order to achieve model verification with the post-flood data. It was found that the most important parameters that affect the timing and magnitude of the peak discharge are the storage coefficient, the impervious rate and the curve number, as well as the time of concentration. Rainfall distribution was examined in different time intervals in order to study the effect of the intensity of precipitation on the peak hydrograph. From the precipitation records and according to the size of the watershed, the time step of the precipitation in the simulation model is recommended to be less than an hour. In other areas around the basin of interest, severe storms known as Medicanes that pass over Crete can produce higher precipitation in shorter time intervals. The impact of climate change scenarios results in an increase on the peak discharge by creating precipitation of higher intensity. Furthermore, the intensification of precipitation due to climate change results in higher flood depths and flooded area extent, as well as wave velocities. [ABSTRACT FROM AUTHOR]