scholarly journals Water restrictions under climate change: a Rhone-Mediterranean perspective combining ‘bottom up’ and ‘top- down’ approaches

2018 ◽  
Author(s):  
Eric Sauquet ◽  
Bastien Richard ◽  
Alexandre Devers ◽  
Christel Prudhomme

Abstract. Drought management plans (DMPs) require an overview of future climate conditions for ensuring long term relevance of existing decision-making processes. To that end, impact studies are expected to best reproduce decision-making needs linked with catchment intrinsic sensitivity to climate change. The objective of this study is to apply a risk-based approach through sensitivity, exposure and sustainability assessments to evaluate the vulnerability of current DMPs operating in the Rhône-Méditerranée (RM) district to future climate projections. After inspection of legally-binding water restrictions (WR) from the DMPs in the RM district, a framework to derive WR durations was developed based on harmonized low-flow indicators. Whilst the framework could not perfectly reproduce all WR ordered by state services, as deviations from socio-political factors could not be included, it enabled to identify most WRs under current baseline, and to quantify the sensitivity of WR duration to a wide range of perturbed climates for 106 catchments. Four classes of responses were found across the RM district. Using the drought of 2011 to define a critical threshold of acceptable WR, the analysis showed that catchments in mountainous areas, highly sensitive to temperature changes, are also the most predisposed to future restrictions under projected climate changes considering current DMPs whilst catchments around the Mediterranean Sea, mainly sensitive to precipitation changes, were less vulnerable to projected climatic changes. The tools developed enable a rapid assessment of the effectiveness of current DMPs under climate change, and can be used to prioritize review of the plans for those most vulnerable basins.

2019 ◽  
Vol 23 (9) ◽  
pp. 3683-3710 ◽  
Author(s):  
Eric Sauquet ◽  
Bastien Richard ◽  
Alexandre Devers ◽  
Christel Prudhomme

Abstract. Drought management plans (DMPs) require an overview of future climate conditions for ensuring long-term relevance of existing decision-making processes. To that end, impact studies are expected to best reproduce decision-making needs linked with catchment intrinsic sensitivity to climate change. The objective of this study is to apply a risk-based approach through sensitivity, exposure and performance assessments to identify where and when, due to climate change, access to surface water constrained by legally binding water restrictions (WRs) may question agricultural activities. After inspection of legally binding WRs from the DMPs in the Rhône–Mediterranean (RM) district, a framework to derive WR durations was developed based on harmonized low-flow indicators. Whilst the framework could not perfectly reproduce all WR ordered by state services, as deviations from sociopolitical factors could not be included, it enabled the identification of most WRs under the current baseline and the quantification of the sensitivity of WR duration to a wide range of perturbed climates for 106 catchments. Four classes of responses were found across the RM district. The information provided by the national system of compensation to farmers during the 2011 drought was used to define a critical threshold of acceptable WR that is related to the current activities over the RM district. The study finally concluded that catchments in mountainous areas, highly sensitive to temperature changes, are also the most predisposed to future restrictions under projected climate changes considering current DMPs, whilst catchments around the Mediterranean Sea were found to be mainly sensitive to precipitation changes and irrigation use was less vulnerable to projected climatic changes. The tools developed enable a rapid assessment of the effectiveness of current DMPs under climate change and can be used to prioritize review of the plans for those most vulnerable basins.


2017 ◽  
Vol 8 (4) ◽  
pp. 652-674 ◽  
Author(s):  
Mohsen Nasseri ◽  
Banafsheh Zahraie ◽  
Leila Forouhar

Abstract In this paper, two approaches to assess the impacts of climate change on streamflows have been used. In the first approach (direct), a statistical downscaling technique was utilized to predict future streamflows based on large-scale data of general circulation models (GCMs). In the second approach (indirect), GCM outputs were downscaled to produce local climate conditions which were then used as inputs to a hydrological simulation model. In this article, some data-mining methods such as model-tree, multivariate adaptive regression splines and group method of data handling were utilized for direct downscaling of streamflows. Projections of HadCM3 model for A2 and B2 SRES scenarios were also used to simulate future climate conditions. These evaluations were done over three sub-basins of Karkheh River basin in southwest Iran. To achieve a comprehensive assessment, a global uncertainty assessment method was used to evaluate the results of the models. The results indicated that despite simplifications included in the direct downscaling, this approach is accurate enough to be used for assessing climate change impacts on streamflows without computational efforts of hydrological modeling. Furthermore, comparing future climate projections, the uncertainty associated with elimination of hydrological modeling is estimated to be high.


2020 ◽  
Author(s):  
Koen De Ridder ◽  
Filip Lefebre ◽  
Eline Vanuytrecht ◽  
Julie Berckmans ◽  
Hendrik Wouters

<p>Biodiversity is increasingly under pressure from climate change, which affects the habitat suitability for species as well as the efficiency of ecosystem services. Management of these issues, for instance through ecosystem restoration or species dispersal measures, is often hindered by a lack of appropriate information about (future) climate conditions.  To address this, an operational Sectoral Information System (SIS) for the Biodiversity sector (SIS Biodiversity) is designed within the Copernicus programme Climate Change Service (C3S). This new SIS provides tailored bio-climatic indicators and applications, and delivers novel evidence regarding impacts of past, present and future climate. As such, it provides support to decision making challenges that are currently facing unmet climate data needs.<br> <br>The new climate service for SIS Biodiversity will be demonstrated, including the outline, workflow and outcomes of the use cases. The service is built upon the Copernicus Data Store platform (CDS; ), and takes into account (1) the barriers in ongoing bio-climate assessments and (2) the user requirements of diverse stakeholders (e.g. researcher institutes, local NGO’s, the International Union for Conservation of Nature and Natural Resources (IUCN),…). These have been collected during workshops and bilateral meetings in 2019. A common barrier is the lack of reliable and high-resolution information about states and dynamics of the soil, sea, ice and air for the past and the future climate. Therefore, the service provides relevant bio-climatic indicators on the basis of a wealth of available variables from the latest ERA5 reanalysis datasets and the CMIP5 global climate projections available in CDS. In order to provide information at high resolution and minimize inconsistencies between observed and modelled variables, different downscaling and bias-correction techniques are applied. A common requirement is a universal and flexible interface to the bio-climatic indicators in an easy-to-use and coherent platform that is applicable for different fauna and flora species of interest. Therefore, different applications have been developed within CDS for generating bio-climate suitability envelopes from the high-resolution indicators and to evaluate climate suitability and impacts for the species under present and future climate. Finally, the service is currently tested and refined on the basis of specific use cases. Special attention is given to their transferability to other global and topical studies, hence maximizing external user uptake throughout existing research and policy networks.</p>


2019 ◽  
Vol 42 (3) ◽  
pp. 987-1000 ◽  
Author(s):  
Dongli Fan ◽  
Honglin Zhong ◽  
Biao Hu ◽  
Zhan Tian ◽  
Laixiang Sun ◽  
...  

Abstract Chinese Medicinal Yam (CMY) has been prescribed as medicinal food for thousand years in China by Traditional Chinese Medicine (TCM) practitioners. Its medical benefits include nourishing the stomach and spleen to improve digestion, replenishing lung and kidney, etc., according to the TCM literature. As living standard rises and public health awareness improves in recent years, the potential medicinal benefits of CMY have attracted increasing attention in China. It has been found that the observed climate change in last several decades, together with the change in economic structure, has driven significant shift in the pattern of the traditional CMY planting areas. To identify suitable planting area for CMY in the near future is critical for ensuring the quality and supply quantity of CMY, guiding the layout of CMY industry, and safeguarding the sustainable development of CMY resources for public health. In this study, we first collect 30-year records of CMY varieties and their corresponding phenology and agro-meteorological observations. We then consolidate these data and use them to enrich and update the eco-physiological parameters of CMY in the agro-ecological zone (AEZ) model. The updated CMY varieties and AEZ model are validated using the historical planting area and production under observed climate conditions. After the successful validation, we use the updated AEZ model to simulate the potential yield of CMY and identify the suitable planting regions under future climate projections in China. This study shows that regions with high ecological similarity to the genuine and core producing areas of CMY mainly distribute in eastern Henan, southeastern Hebei, and western Shandong. The climate suitability of these areas will be improved due to global warming in the next 50 years, and therefore, they will continue to be the most suitable CMY planting regions.


Author(s):  
Pietro Croce ◽  
Paolo Formichi ◽  
Filippo Landi

<p>The impact of climate change on climatic actions could significantly affect, in the mid-term future, the design of new structures as well as the reliability of existing ones designed in accordance to the provisions of present and past codes. Indeed, current climatic loads are defined under the assumption of stationary climate conditions but climate is not stationary and the current accelerated rate of changes imposes to consider its effects.</p><p>Increase of greenhouse gas emissions generally induces a global increase of the average temperature, but at local scale, the consequences of this phenomenon could be much more complex and even apparently not coherent with the global trend of main climatic parameters, like for example, temperature, rainfalls, snowfalls and wind velocity.</p><p>In the paper, a general methodology is presented, aiming to evaluate the impact of climate change on structural design, as the result of variations of characteristic values of the most relevant climatic actions over time. The proposed procedure is based on the analysis of an ensemble of climate projections provided according a medium and a high greenhouse gas emission scenario. Factor of change for extreme value distribution’s parameters and return values are thus estimated in subsequent time windows providing guidance for adaptation of the current definition of structural loads.</p><p>The methodology is illustrated together with the outcomes obtained for snow, wind and thermal actions in Italy. Finally, starting from the estimated changes in extreme value parameters, the influence on the long-term structural reliability can be investigated comparing the resulting time dependent reliability with the reference reliability levels adopted in modern Structural codes.</p>


2021 ◽  
Author(s):  
Giovanni Di Virgilio ◽  
Jason P. Evans ◽  
Alejandro Di Luca ◽  
Michael R. Grose ◽  
Vanessa Round ◽  
...  

&lt;p&gt;Coarse resolution global climate models (GCM) cannot resolve fine-scale drivers of regional climate, which is the scale where climate adaptation decisions are made. Regional climate models (RCMs) generate high-resolution projections by dynamically downscaling GCM outputs. However, evidence of where and when downscaling provides new information about both the current climate (added value, AV) and projected climate change signals, relative to driving data, is lacking. Seasons and locations where CORDEX-Australasia ERA-Interim and GCM-driven RCMs show AV for mean and extreme precipitation and temperature are identified. A new concept is introduced, &amp;#8216;realised added value&amp;#8217;, that identifies where and when RCMs simultaneously add value in the present climate and project a different climate change signal, thus suggesting plausible improvements in future climate projections by RCMs. ERA-Interim-driven RCMs add value to the simulation of summer-time mean precipitation, especially over northern and eastern Australia. GCM-driven RCMs show AV for precipitation over complex orography in south-eastern Australia during winter and widespread AV for mean and extreme minimum temperature during both seasons, especially over coastal and high-altitude areas. RCM projections of decreased winter rainfall over the Australian Alps and decreased summer rainfall over northern Australia are collocated with notable realised added value. Realised added value averaged across models, variables, seasons and statistics is evident across the majority of Australia and shows where plausible improvements in future climate projections are conferred by RCMs. This assessment of varying RCM capabilities to provide realised added value to GCM projections can be applied globally to inform climate adaptation and model development.&lt;/p&gt;


2021 ◽  
Author(s):  
luis Augusto sanabria ◽  
Xuerong Qin ◽  
Jin Li ◽  
Robert Peter Cechet

Abstract Most climatic models show that climate change affects natural perils' frequency and severity. Quantifying the impact of future climate conditions on natural hazard is essential for mitigation and adaptation planning. One crucial factor to consider when using climate simulations projections is the inherent systematic differences (bias) of the modelled data compared with observations. This bias can originate from the modelling process, the techniques used for downscaling of results, and the ensembles' intrinsic variability. Analysis of climate simulations has shown that the biases associated with these data types can be significant. Hence, it is often necessary to correct the bias before the data can be reliably used for further analysis. Natural perils are often associated with extreme climatic conditions. Analysing trends in the tail end of distributions are already complicated because noise is much more prominent than that in the mean climate. The bias of the simulations can introduce significant errors in practical applications. In this paper, we present a methodology for bias correction of climate simulated data. The technique corrects the bias in both the body and the tail of the distribution (extreme values). As an illustration, maps of the 50 and 100-year Return Period of climate simulated Forest Fire Danger Index (FFDI) in Australia are presented and compared against the corresponding observation-based maps. The results show that the algorithm can substantially improve the calculation of simulation-based Return Periods. Forthcoming work will focus on the impact of climate change on these Return Periods considering future climate conditions.


2018 ◽  
Vol 77 (11) ◽  
pp. 2578-2588 ◽  
Author(s):  
Hjalte Jomo Danielsen Sørup ◽  
Steffen Davidsen ◽  
Roland Löwe ◽  
Søren Liedtke Thorndahl ◽  
Morten Borup ◽  
...  

Abstract The technical lifetime of urban water infrastructure has a duration where climate change has to be considered when alterations to the system are planned. Also, models for urban water management are reaching a very high complexity level with, for example, decentralized stormwater control measures being included. These systems have to be evaluated under as close-to-real conditions as possible. Long term statistics (LTS) modelling with observational data is the most close-to-real solution for present climate conditions, but for future climate conditions artificial rainfall time series from weather generators (WGs) have to be used. In this study, we ran LTS simulations with four different WG products for both present and future conditions on two different catchments. For the present conditions, all WG products result in realistic catchment responses when it comes to the number of full flowing pipes and the number and volume of combined sewer overflows (CSOs). For future conditions, the differences in the WGs representation of the expectations to climate change is evident. Nonetheless, all future results indicate that the catchments will have to handle more events that utilize the full capacity of the drainage systems. Generally, WG products are relevant to use in planning of future changes to sewer systems.


2021 ◽  
Author(s):  
Katharina Enigl ◽  
Matthias Schlögl ◽  
Christoph Matulla

&lt;p&gt;Climate change constitutes a main driver of altering population dynamics of spruce bark beetles (&lt;em&gt;Ips typographus&lt;/em&gt;) all over Europe. Their swarming activity as well as development rate are strongly dependent on temperature and the availability of brood trees. Especially over the last years, the latter has substantially increased due to major drought events which led to a widespread weakening of spruce stands. Since both higher temperatures and longer drought periods are to be expected in Central Europe in the decades ahead, foresters face the challenges of maintaining sustainable forest management and safeguarding future yields. One approach used to foster decision support in silviculture relies on the identification of possible alternative tree species suitable for adapting to expected future climate conditions in threatened regions.&amp;#160;&lt;/p&gt;&lt;p&gt;In this study, we focus on the forest district of Horn, a region in Austria&amp;#8216;s north east that is beneficially influenced by the mesoclimate of the Pannonian basin. This fertile yet dry area has been severely affected by mass propagations of &lt;em&gt;Ips typographus&lt;/em&gt; due to extensive droughts since 2017, and consequently has suffered from substantial forest damage in recent years. The urgent need for action was realized and has expedited the search for more robust alternative species to ensure sustainable silviculture in the area.&lt;/p&gt;&lt;p&gt;The determination of suitable tree species is based on the identification of regions whose climatic conditions in the recent past are similar to those that are to be expected in the forest district of Horn in the future. To characterize these conditions, we consider 19 bioclimatic variables that are derived from monthly temperature and rainfall values. Using downscaled CMIP6 projections with a spatial resolution of 2.5 minutes, we determine future conditions in Horn throughout the 21st century. By employing 20-year periods from 2021 to 2100 for the scenarios SSP1-26, SSP2-45, SSP3-70 and SSP5-85,&amp;#160; and comparing them to worldwide past climate conditions, we obtain corresponding bioclimatic regions for four future time slices until the end of the century. The Euclidian distance is applied as measure of similarity, effectively yielding similarity maps on a continuous scale. In order to account for the spatial variability within the forest district, this procedure is performed for the colder northwest and the warmer southeast of the area, individually seeking similar bioclimatic regions for each of these two subregions. Results point to Eastern Europe as well as the Po Valley in northern Italy as areas exhibiting the highest similarity to the future climate in this North-Eastern part of Austria.&lt;/p&gt;


2021 ◽  
Author(s):  
Kepa Solaun ◽  
Gerard Alleng ◽  
Adrián Flores ◽  
Chiquita Resomardono ◽  
Katharina Hess ◽  
...  

Suriname is highly vulnerable to the effects of climate change. Among the factors that exacerbate its vulnerability are its dependency on fossil fuels, the degradation of important ecosystems (e.g., mangroves), and the fact that 87% of the population, and most of the countrys economic activity is located within the low-lying coastal area. Many sectors are at risk of suffering losses and damage caused by gradual changes and extreme events related to climate change. For Suriname to develop sustainably, it should incorporate climate change and its effects into its decision-making process based on scientific- evidence. The State of the Climate Report analyzes Surinames historical climate (1990-2014) and provides climate projections for three time horizons (2020-2044, 2045-2069, 2070-2094) through two emissions scenarios (intermediate/ SSP2-4.5 and severe/ SSP5-8.5). The analysis focuses on changes in sea level, temperature, precipitation, relative humidity, and winds for the seven subnational locations of Paramaribo, Albina, Bigi Pan MUMA, Brokopondo, Kwamalasamutu, Tafelberg Natural Reserve, and Upper Tapanahony. The Report also analyzes climate risk for the countrys ten districts by examining the factors which increase their exposure and vulnerability on the four most important sectors affected by climate change: infrastructure, agriculture, water, and forestry, as well as examining the effects across the sectors. The State of the Climate Report provides essential inputs for Suriname to develop and update its climate change policies and targets. These policies and targets should enable an adequate mainstreaming of climate change adaptation and resilience enhancementinto day-to-day government operations. It is expected that the Report will catalyze similar efforts in the future to improve decision-making by providing science-based evidence.


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