Intensity Of Extreme Events Research Articles

Evaluating the extent and impact of the extreme Storm Gloria on Posidonia oceanica seagrass meadows

Extreme storms can trigger abrupt and often lasting changes in ecosystems by affecting foundational (habitat-forming) species. While the frequency and intensity of extreme events are projected to increase under climate change, its impacts on seagrass ecosystems remain poorly documented. In January 2020, the Spanish Mediterranean coast was hit by Storm Gloria, one of the most devastating recent climate events in terms of intensity and duration. We conducted rapid surveys of 42 Posidonia oceanica meadows across the region to evaluate the extent and type of impact (burial, unburial and uprooting). We investigated the significance of oceanographic (wave impact model), geomorphological (latitude, depth, exposure), and structural (patchiness) factors in predicting impact extent and intensity. The predominant impact of Storm Gloria was shoot unburial. More than half of the surveyed sites revealed recent unburial, with up to 40 cm of sediment removed, affecting over 50 % of the meadow. Burial, although less extensive, was still significant, with 10–80 % of meadow cover being buried under 7 cm of sediment, which is considered a survival threshold for P. oceanica. In addition, we observed evident signs of recently dead matte in some meadows and large amounts of detached drifting shoots on the sea bottom or accumulated as debris on the beaches. Crucially, exposed and patchy meadows were much more vulnerable to the overall impact than sheltered or continuous meadows. Given how slow P. oceanica is able to recover after disturbances, we state that it could take from decades to centuries for it to recoup its losses. Seagrass ecosystems play a vital role as coastal ecological infrastructure. Protecting vulnerable meadows from anthropogenic fragmentation is crucial for ensuring the resilience of these ecosystems in the face of the climate crisis.

Ability of the GRAPES Ensemble Forecast Product to Forecast Extreme Temperatures over the Tibetan Plateau

Due to climate change, extreme temperature events are receiving increased attention. Based on the climate state deviation and threat score (TS), the ability of the Global/Regional Assimilation and Prediction System (GRAPES) ensemble model to forecast extreme temperature events was examined. The “optimal” Extreme Forecast Index (EFI) was derived for plateau forecasting, and its predictability was examined based on the receiver operating characteristic (ROC) curve method. Meanwhile, the applicability of the Shift of Tails (SOT) index to extreme temperature forecasting was analyzed using extreme temperature cases. Results showed that the GRAPES model has a warm bias for both summer extreme high temperature and winter extreme low temperature, and the warm bias decreases slightly with an increase in the forecasting lead time. The ensemble mean and median forecasts are less effective, and the maximum value is more predictable. However, for the ensemble forecast model, the extreme information in its forecast is more unstable, and the limitation of the extreme temperature forecast in the plateau region is higher. With different forecast lead times, the TS tends to increase and then decrease with an increase in the EFI threshold, which means that there is an optimal EFI. The optimal EFI thresholds for summer extreme high-temperature forecasts are all less than −0.5, while for winter extreme low-temperature forecasts, they are almost all less than 0. From the ROC curves, the EFI has a certain level of predictability for summer extreme high temperatures but poorer forecasting effects. Furthermore, the EFI has some predictability for extreme summer high temperatures, but the prediction effect is poor. For the extremely low temperatures in winter, which are poorly predicted by the model itself, post-processing of the extreme information predicted by the model with the EFI can improve the forecasting effect of the model. Through analysis of individual cases, it was found that the extreme intensity reflected by the SOT_+ (0.9) index of the model was closer to reality for the prediction of extremely high temperatures, whereas for the prediction of extremely low temperatures, the extreme intensity indicated by the SOT_− (0.1) index of the model was weaker. Therefore, the SOT index can play an important auxiliary role in the prediction of the intensity of extreme events based on the EFI.

Adaptation to heat and concomitant environmental risks in Europe: a GAP Analysis

Abstract Background Climate change is increasing the frequency and intensity of extreme events like heatwaves, wildfires and droughts. Within the ENBEL project, a GAP analysis was carried out to provide evidence on vulnerability factors of concomitant environmental risks during heat waves and promote the implementation of public health response. Aim To assess the level of implementation of heat wave and co-exposures (air pollution, wildfires and drought) response actions and to identify gaps and needs for public health adaptation in Europe. Methods A scoping review was performed to identify clinical and social vulnerabilities to heatwaves and concomitant exposures and prevention measures in place. Interviews with key stakeholders will provide additional information on response measures addressed to vulnerable groups as well as identifying needs and gaps for adaptation. Furthermore, an assessment of how Covid-19 recovery plans and funding in Europe are supporting climate adaptation and health care resilience was carried out. Results From the literature review interventions mainly focused on outdoor workers and athletes, include guidance, plans and actions on hydration, rest in the shade, cooling clothes and food, as well as acclimatization procedures. The elderly are among those consistently targeted in heat prevention plans, with health and social care surveillance, tele-medicine and awareness campaigns carried out during summer in several high-income countries. Regarding multiple environmental exposures, studies on preventive measures are scarce, and stakeholders reported the need for further research, sharing of knowledge and evaluation of measures to enhance action. Conclusions Although Covid-19 recovery funding is providing marginal benefits for health systems resilience, key barriers to climate adaptation still remain in terms of limited resources, personnel capacity; governance constraints and unclear policy remit.

Changes in compound flood event frequency in northern and central Europe under climate change

The simultaneous occurrence of increased river discharge and high coastal water levels may cause compound flooding. Compound flood events can potentially cause greater damage than the separate occurrence of the underlying extreme events, making them essential for risk assessment. Even though a general increase in the frequency and/or severity of compound flood events is assumed due to climate change, there have been very few studies conducted for larger regions of Europe. Our work, therefore, focuses on the high-resolution analysis of changes in extreme events of coastal water levels, river discharge, and their concurrent appearance at the end of this century in northern and central Europe (2070–2099). For this, we analyze downscaled data sets from two global climate models (GCMs) for the two emissions scenarios RCP2.6 and RCP8.5. First, we compare the historical runs of the downscaled GCMs to historical reconstruction data to investigate if they deliver comparable results for northern and central Europe. Then we study changes in the intensity of extreme events, their number, and the duration of extreme event seasons under climate change. Our analysis shows increases in compound flood events over the whole European domain, mostly due to the rising mean sea level. In some areas, the number of compound flood event days increases by a factor of eight at the end of the current century. This increase is concomitant with an increase in the annual compound flood event season duration. Furthermore, the sea level rise associated with a global warming of 2K will result in double the amounts of compound flood event days for nearly every European river estuary considered.

Spatio-Temporal Evolution of Rainfall over the Period 1981–2020 and Management of Surface Water Resources in the Nakanbe–Wayen Watershed in Burkina Faso

Spatio-temporal analysis of rainfall trends in a watershed is an effective tool for sustainable water resources management, as it allows for an understanding of the impacts of these changes at the watershed scale. The objective of the present study is to analyze the impacts of climate change on the availability of surface water resources in the Nakanbe–Wayen watershed over the period from 1981 to 2020. The analysis was conducted on in situ rainfall data collected from 14 meteorological stations distributed throughout the watershed and completed with CHIRPS data. Ten precipitation indices, recommended by the ETCCDI (Expert Team on Climate Change Detection and Indices), were calculated using the RClimDex package. The results show changes in the distribution of annual precipitation and an increasing trend in annual precipitation. At the same time, a trend towards an increase in the occurrence and intensity of extreme events was also observed over the last 4 decades. In light of these analyses, it should be emphasized that the increase in precipitation observed in the Nakanbe–Wayen watershed is induced by the increase in the occurrence and intensity of events, as a trend towards an increase in persistent drought periods (CDD) is observed. This indicates that the watershed is suffering from water scarcity. Water stress and water-related hazards have a major impact on communities and ecosystems. In these conditions of vulnerability, the development of risk-management strategies related to water resources is necessary, especially at the local scale. This should be formulated in light of observed and projected climate extremes in order to propose an appropriate and anticipated management strategy for climate risks related to water resources at the watershed scale.

Nearshore Observations and Modeling: Synergy for Coastal Flooding Prediction

Coastal inundation has recently started to require significant attention worldwide. The increasing frequency and intensity of extreme events (sea storms, tsunami waves) are highly stressing coastal environments by endangering a large number of residential areas, ecosystems, and tourist facilities, and also leading to potential environmental risks. Predicting such events and the generated coastal flooding is thus of paramount importance and can be accomplished by exploiting the potential of different tools. An example is the combination of remote sensors, like marine radars, with numerical models. Specifically, while instruments like X-band radars are able to precisely reconstruct both wave field and bathymetry up to some kilometers off the coast, wave-resolving Boussinesq-type models can reproduce the wave propagation in the nearshore area and the consequent coastal flooding. Hence, starting from baseline simulations of wave propagation and the conversion of water elevation results into radar images, the present work illustrates the reconstruction of coastal data (wave field and seabed depth) using a specifically suited data processing method, named the “Local Method”, and the use of such coastal data to run numerical simulations of coastal inundation in different scenarios. Such scenarios were built using two different European beaches, i.e., Senigallia (Italy) and Oostende (Belgium), and three different directional spreading values to evaluate the performances in cases of either long- or short-crested waves. Both baseline and inundation simulations were run using the FUNWAVE-TVD solver. The overall validation of the methodology, in terms of maximum inundation, shows its good performance, especially in cases of short-crested wind waves. Furthermore, the application on Oostende Beach demonstrates that the present methodology might work using only open-access tools, providing an easy investigation of coastal inundation and potential low-cost integration into early warning systems.

Effects of extreme melt events on ice flow and sea level rise of the Greenland Ice Sheet

Abstract. Over the past decade, Greenland has experienced several extreme melt events, the most pronounced ones in the years 2010, 2012 and 2019. With progressing climate change, such extreme melt events can be expected to occur more frequently and potentially become more severe and persistent. So far, however, projections of ice loss and sea level change from Greenland typically rely on scenarios which only take gradual changes in the climate into account. Using the Parallel Ice Sheet Model (PISM), we investigate the effect of extreme melt events on the overall mass balance of the Greenland Ice Sheet and the changes in ice flow, invoked by the altered surface topography. As a first constraint, this study estimates the overall effect of extreme melt events on the cumulative mass loss of the Greenland Ice Sheet. We find that the sea level contribution from Greenland might increase by 2 to 45 cm (0.2 % to 14 %) by the year 2300 if extreme events occur more frequently in the future under a Representative Concentration Pathway 8.5 (RCP8.5) scenario, and the ice sheet area might be reduced by an additional 6000 to 26 000 km2 by 2300 in comparison to future warming scenarios without extremes. In conclusion, projecting the future sea level contribution from the Greenland Ice Sheet requires consideration of the changes in both the frequency and intensity of extreme events. It is crucial to individually address these extremes at a monthly resolution as temperature forcing with the same excess temperature but evenly distributed over longer timescales (e.g., seasonal) leads to less sea level rise than for the simulations of the resolved extremes. Extremes lead to additional mass loss and thinning. This, in turn, reduces the driving stress and surface velocities, ultimately dampening the ice loss attributed to ice flow and discharge. Overall, we find that the surface elevation feedback largely amplifies melting for scenarios with and without extremes, with additional mass loss attributed to this feedback having the greatest impact on projected sea level.

Combating Climate Change and Global Warming for a Sustainable Living in Harmony with Nature

As humanity has been polluting the atmosphere with greenhouse gases, the planet is getting warmed up which is triggering the frequency and the intensity of extreme events like heat waves, dry conditions, wildfires, cyclones, tornadoes, lightning, and massive flooding all over the planet Earth. There is considerable evidence that the concentration of greenhouse gases, especially that of CO2 has steadily increased in the atmosphere as a result of the indiscriminate use of fossil fuels around the world particularly during the last 70 years. The glaciers in the high mountain and polar regions are diminishing fast, sea levels are rising, and food production is being affected severely in certain parts of the world. In fact, the changing climate has currently become one of the major threats to the survival of civilization. The world scientific communities are warning of a climate emergency and requesting the decision makers to promptly respond and act to sustain life on planet Earth. To deliver net zero emissions by the year 2050, the whole world must phase out the technologies such as coal-powered thermal plants and diesel/petrol/gasoline-powered vehicles which release abundant amounts of CO2 and other greenhouse gases into the atmosphere and invest in the development of clean energies such as hydel, wind, solar, space-solar, and nuclear energies. This transition to a low carbon economy with the help of these technologies together with other technologies such as hydrogen fuel, fuel cells, electric vehicles, and massive plantations is expected to take our planet Earth to a safe zone in the coming 20-30 years.

RUNUP OF A SURFACE SOLITARY WAVE ON A THIN VERTICAL SEMI-SUBMERSED SCREEN

Global climate changes lead to an increase in the number and intensity of extreme events in the seas and oceans (tsunamis, floods, storm surges, etc.). This can have catastrophic consequences involving the destruction of civil infrastructure, the flooding of large areas of recreational land, the loss of life, and can also adversely affect water quality, sediment transport, and habitats for living organisms. The creation of artificial berms on the seabed and breakwater piers changes significantly the parameters of wave processes, reducing destructive effect of waves in the coastal zone. But the use of traditional coastal protection structures (dams, piers, breakwaters) is not always efficient and economically reasonable. Thin permeable barriers are increasingly being considered as an alternative option in providing economic and ecological protection of coastal areas. The purpose of this research is to substantiate the effectiveness of vertical semi-submerged walls for protection the shores of natural reservoirs from the destructive energy of surface waves. Such a structure is non-permeable near the free surfacer, and is supported by piles at some distance from the bottom, which allows the flow of water and sediments. The physical simulation of the interaction of a nonlinear solitary wave, which is considered as a tsunami model, with a semi-submerged thin vertical barrier is performed in the experimental channel to evaluate the effectiveness of vertical wave barriers against the destructive energy of long waves. It was found that interaction of a solitary wave with an overhanging vertical wall leads to generation both of the reflected wave, due to roll of the incident wave on the structure, and the transmitted wave, which is formed after the liquid mass passes through the gap between the bottom and the wall. Quantitative characteristics of the interaction of the wave with the obstacle were obtained with the help of capacitive sensors, which were installed along the main axis of the laboratory channel to record the free surface disturbances caused by the propagation of the wave in the channel, its reflection from the wave screen and its transmission downstream. The processing of the received data made it possible to estimate the parameters of a solitary wave, which was formed in the channel by the impact of a heavy body on the water surface, those are the amplitude, length, and velocity of wave propagation. The energy attenuation of a solitary wave is estimated, which is an important characteristic of the channel and makes it possible to obtain more accurate values of reflection and transmission coefficients. Evaluations of wave reflection and transmission coefficients show that thin partially submerged vertical barriers are sufficiently effective in reducing the energy of nonlinear solitary waves although they do not suppress the waves completely. The depth of the screen-type permeable obstacle immersion relative to the free surface has a significant influence on the reflection/transmission coefficients and its effectiveness, accordingly. It has been established that semi-submerged obstacles can dissipate up to 60% of the incident wave energy.

Weather, climate change, and transport: a review

Transportation is affected by weather and extreme weather events, and there is evidence that heatwaves, heavy precipitation, storms, wildfires, and floods increasingly affect transport infrastructures, operations, and travel behavior. Climate change is expected to reinforce this trend, as mean weather parameters change, and the frequency and intensity of extreme events increases. This paper summarizes interrelationships of weather and transport for different transport modes from both supply and demand side perspectives on the basis of a literature review. To further explore the complexity of these interrelationships, it also evaluates news items (n = 839) in a sample of global media news outlets covering the world and population-dense world regions. Results confirm that extreme events have become disruptive of transport systems at the micro and macro scale, also affecting transport behavior. There are implications for environment, economy, technology, health, and society. Interrelationships are illustrated and discussed: Climatic impact drivers can be expected to increase transport vulnerabilities and risks, and have relevance for transport planning and adaptation.

Will climate change favor exotic grasses over native ecosystem engineer species in the Amazon Basin?

Several anthropic disturbances, including deforestation, fires, the building of roads and dams, have intensified in Amazon in last decades. These disturbances contribute to an increase in the occurrence and intensity of extreme events, such as more frequent floods and more severe droughts, due to climate change. Along the Amazonian rivers, aquatic herbaceous plants, mainly of the Poaceae family, are very abundant and produce up to three times more biomass than the adjacent flooded forests, and some are considered ecosystem engineers given their structuring role in these environments. Invasive grasses have spread through the Neotropics and are gradually entering the Amazon via the Arc of Deforestation. These invasive species often attain high coverage, suppress other species, and become dominant in both disturbed and pristine habitats. The aim of this study was to establish the current and future distribution patterns of two native ecosystem engineer species (Echinochloa polystachya and Paspalum fasciculatum) and two invasive species (Urochloa brizantha and Urochloa decumbens) in the Amazon Basin. To predict the future climate, we used three scenarios, namely SSP1–2.6, SSP3–7.0 and SSP5–8.5 for the years 2040, 2080 and 2100, to project climatically suitable areas. The current climatically suitable range for the native ecosystem engineer species was estimated at 33–35% of the Amazon Basin, while the invasive ones have a range of 53–84% in potential climatically suitable areas. A decrease in the areas of suitability of the two ecosystem engineer species, E. polystachya and P. fasciculatum, was observed in all scenarios and years, while only the invasive U. brizantha showed an increase in suitable areas in all years. These results raise concerns about the invasion of grasses with high aggressive potential that could result in the exclusion of native ecosystem engineer species and their ecological roles.

Changing intensity of hydroclimatic extreme events revealed by GRACE and GRACE-FO

Distortion of the water cycle, particularly of its extremes (droughts and pluvials), will be among the most conspicuous consequences of climate change. Here we applied a novel approach with terrestrial water storage observations from the GRACE and GRACE-FO satellites to delineate and characterize 1,056 extreme events during 2002–2021. Dwarfing all other events was an ongoing pluvial that began in 2019 and engulfed central Africa. Total intensity of extreme events was strongly correlated with global mean temperature, more so than with the El Niño Southern Oscillation or other climate indicators, suggesting that continued warming of the planet will cause more frequent, more severe, longer and/or larger droughts and pluvials. In three regions, including a vast swath extending from southern Europe to south-western China, the ratio of wet to dry extreme events decreased substantially over the study period, while the opposite was true in two regions, including sub-Saharan Africa from 5° N to 20° N. How will climate change affect wet and dry extreme events around the world? On the basis of terrestrial water storage observations and a novel clustering algorithm, this study shows that the intensity of such events has been increasing with global warming.

On the degradation of forest ecosystems by extreme events: Statistical Model Checking of a hybrid model

In this paper, we study the vulnerability of forest ecosystems perturbed by extreme events, such as those arising from climate change. To investigate the complex interactions between the biological dynamics of the forest and the climatic activity, we construct an original hybrid model, obtained by coupling a continuous reaction–diffusion system, which describes the spatio-temporal dynamics of the forest ecosystem, with a discrete probabilistic process, which models the possible occurrences of extreme events. Properties of ecological interest are considered: invariance of the persistence equilibrium, attraction to the extinction equilibrium and emergence of degraded states. Those properties of the hybrid model are verified through an extension of the Statistical Model Checking framework. We establish the existence of a threshold above which the persistence equilibrium of the forest ecosystem is compromised and give a numerical assessment of this threshold in terms of the probability and intensity of extreme events. We also present non-trivial parameter conditions for which the forest ecosystem converges to a degraded savanna-like state.

Land use and adaptive governance under climate change: Analysis of four cases in pastoral areas of China

Under the impact of climate change, pastoral areas of China have experienced increasing frequency and intensity of extreme events, which has brought more challenges to pastoralists’ livelihood. Adaptive governance refers to increasing resilience through collaborative, flexible, and learning-oriented management on different scales to form a set of political, social, economic, and administrative systems for the development, management, and allocation of resources. As such, it provides a useful framework and benchmark for enhancing adaptive capacity. However, how to implement adaptive governance in practice is still an unresolved problem. Under the current property regime, which individualized grassland use rights with wire fences built to demarcate boundaries, pastoralists of different places have tried to increase their adaptability to reduce the loss caused by disasters. Some succeeded, but some failed. Based on household surveys and an comparative analysis of four cases in pastoral areas of China, this article presents their climate change risk and changes in land use arrangements, explores the reasons for their different adaptability by comparing their coping strategies with the adaptive governance features, and finally illustrates the challenges influencing the application of adaptive governance at the local level.

Assessing the Future wind Energy Potential in Portugal Using a CMIP6 Model Ensemble and WRF High-Resolution Simulations

Future wind energy potential over Portugal is assessed, using wind speed data from a WRF regional simulation under the SSP5-8.5 scenario for 2046–2065 and 2081–2100. Data from a CMIP6 multi-model ensemble were also used to assess future changes in the Euro-Atlantic large-scale circulation. CMIP6 results have shown a southward displacement of the mid-latitude jet stream during winter, and a northward displacement during spring, summer, and autumn, which causes the northern winds to strengthen during summer along the north-western Iberian coast. Furthermore, in 2046–2065 the wind power density (WPD) should increase between 25% and 50% off the northwest coast of Portugal and in the Serra da Estrela mountain range during summer, which is in agreement with the CMIP6 global ensemble projections. Analyses of WPD’s 2046–2065 daily variability of offshore north-western Portugal reveal a variability increase during winter, spring and summer, as well as more intense extreme WPD events, and less intense extreme events during autumn. The WPD’s 2046–2065 inter-annual variability should increase off the northwest coast, and decrease along the central western and southern coasts, whereas it should increase in the entire studied area in 2081–2100, apart from the northern mountain regions and Cape Raso.

An Approach for the Validation of a Coastal Erosion Vulnerability Index: An Application in Sicily

In recent decades, coastal erosion phenomena have increased due to climate change. The increased frequency and intensity of extreme events and the poor sediment supply by anthropized river basins (dams, river weirs, culverts, etc.) have a crucial role in coastal erosion. Therefore, an integrated analysis of coastal erosion is crucial to produce detailed and accurate coastal erosion vulnerability information to support mitigation strategies. This research aimed to assess the erosion vulnerability of the Sicilian coast, also including a validation procedure of the obtained scenario. The coastal vulnerability was computed by means of the CeVI (Coastal Erosion Vulnerability Index) approach, which considers physical indicators such as geomorphology and geology, coastal slope, sea storms, wave maxima energy flux and sediment supply to river mouths. Each indicator was quantified using indexes which were assessed considering transects orthogonal to the coastline in 2020. These transects were clustered inside natural compartments called littoral cells. Each cell was assumed to contain a complete cycle of sedimentation and not to have sediment exchange with the near cells. Physical parameters were identified to define a new erosion vulnerability index for the Sicilian coast. By using physical indexes (geological/geomorphological, erosion/sediment supply, sea storms, etc.), the CeVI was calculated both for each littoral cell and for the transects that fall into retreating/advancing coastal areas. The vulnerability index was then validated by comparing CeVI values and the coastline change over time. The validation study showed a direct link between the coastline retreat and high values of CeVI. The proposed method allowed for a detailed mapping of the Sicilian coastal vulnerability, and it will be useful for coastal erosion risk management purposes.

The 50- and 100-year Exceedance Probabilities as New and Convenient Statistics for a Frequency Analysis of Extreme Events: An Example of Extreme Precipitation in Israel

The misinterpreted statistics of extreme events’ probability in drainage design codes can lead to an insufficient capacity of drainage systems. This is one of the main factors of frequent floods, especially in coastal cities. Heavy rainfalls, the so-called “1-in-50-year” or “1-in-100-year” events followed by floods, may occur there every 2–3 years. We hope to contribute to the correct understanding of extreme events’ statistics. To achieve this goal, we first recall the technique of calculating the exceedance probability of the extreme event over a period of years. Then, to illustrate the theoretical results (among which is the well-known 63.2% minimal exceedance probability over a period of N years for an event with a 1/N annual exceedance probability), we use the rainfall intensity data archived at the Israel Meteorological Service for 1938–2021. We estimate their exceedance probabilities over periods of 50 and 100 years and offer the latter as convenient measures for comparative analysis of the intensity of extreme events. These illustrations highlight the importance of considering return periods that are significantly longer than the 50- or 100-year periods currently used in drainage design, to reduce the risk of flooding and damage caused by heavy rainfalls.

Spatiotemporal Patterns of Extreme Precipitation Events over Jhelum River Basin

Climate change has a wide range of impacts on Pakistan’s water resources system, followed by increased magnitude, frequency and intensity of extreme events. Therefore, investigating the variations in extreme climatic events is vital in planning and developing agriculture and water conservation projects. Hence, the present study investigated the spatiotemporal variability of extreme precipitation indices (EPIs) over the Jhelum River basin (JRB) using the Mann-Kendall (MK) and innovative trend analysis (ITA) methods. In addition, variations in the event-based extreme precipitation (EEPs) and time distribution patterns (TDPs) were analyzed because EPIs considered the daily precipitation values only and the combined effect of the extreme events that last for more than 1 day were often neglected. The results show that the fixed and station-related EPIs, i.e., R10, R20, R25, CWD, Prcpt and R95p, exhibited significant decreasing trends at 06, 05, 04, 04, 07 and 05 stations, whereas an increasing trend was evident for consecutive dry days (CDD) at nine stations with a magnitude of 0.33 days/year, indicating a rise in the drought events compared to floods. Moreover, precipitation events with an amount of 40–290 mm, duration of 4–7 days and concentration ratio of 0.7–0.95 were found to be dominant across JRB. Therefore, an increase in the CDD and a decrease in the consecutive wet days (CWD) may change the magnitude, intensity and frequency of extreme precipitation events and consequently pressure the availability of water resources. Therefore, the findings of this study may help understand the precipitation variability over JRB and play a pivotal role in future development projects.

Comparison of taxonomic and size-based approaches to determine the effects of environment and disturbance on invertebrate communities in coastal Chile

• Disturbance from land use change and tsunamis impact Chilean invertebrates. • Aquatic and terrestrial communities respond differently to wetland disturbance. • Coastal wetland invertebrate communities vary with latitudinal gradients. • Disturbance impacts on size vary according to salinity. • Taxonomic diversity and size-based metrics detect different disturbance impacts. The frequency and intensity of extreme events in coastal wetlands is increasing due to climate change. These, in combination with other threats such as habitat loss, can have strong effects on the biodiversity and ecosystem services of coastal wetland ecosystems. Here we examined how traditional (community composition and taxonomic diversity) and alternative indices based on body size (size diversity and the slope of size spectra) respond to single and combined effects of anthropogenic disturbances, extreme event disturbances, and key environmental drivers, for both aquatic and terrestrial invertebrates in Mediterranean coastal wetlands in Chile. We studied 18 coastal wetlands over more than 500 km along the Chilean coast. We applied both univariate (GLMMs and GAMMs) and multivariate statistics (RDA and variation partitioning) to identify additive and non-additive effects on invertebrates. We also examined latitudinal trends, and tested the potential of alternative metrics to detect interactions between disturbances. We found latitude-specific vulnerability to disturbances in Chilean coastal wetlands. Non-additive effects were more important for aquatic invertebrates, while additive effects were more important for terrestrial invertebrates. In many cases, disturbance effects depended on the environmental conditions of study sites, especially salinity. This study suggests that size-based metrics may be better than taxonomic metrics at detecting interactions among different disturbances, especially for aquatic invertebrates.

Characterizing groundwater flow in a former uranium mine (Bertholène, France): Present status and future considerations

Study regionBertholène is a former uranium mine in Aveyron, where tailings and waste rocks are stored in a natural valley. This results in acid mine drainage (AMD) at the outlet of the tailings storage facility (TSF), where there is a dedicated water treatment plant. Study focusA detailed data analysis was conducted using data from 13 piezometers and from long-term monitoring of the local climate. A 3D model was developed using MODFLOW to understand groundwater flows at the catchment scale and identify flow paths from the contamination sources within the TSF. Previous geochemical modeling of TSFs had indicated that AMD was expected to occur for 50–100 years, therefore the site must be managed with a long-term view. As climate change may affect not only the recharge but also the frequency and intensity of extreme events, its impact on water balance and water levels at the site has to be studied for the next 100 years. New Hydrological Insights for the RegionData analysis provides information about the unsaturated conditions within the tailings. Then water balance calculations at the TSF outlet validate the contribution of two different water zones. Modeling using the recharge estimation supports the current functioning of the catchment. The impact study of extreme events shows that the water table should not permanently reach the tailings over the next century.