scholarly journals The Water-Energy-Food-Ecosystem Nexus in the Mediterranean: Current Issues and Future Challenges

2021 ◽  
Vol 3 ◽  
Author(s):  
Ad De Roo ◽  
Ioannis Trichakis ◽  
Berny Bisselink ◽  
Emiliano Gelati ◽  
Alberto Pistocchi ◽  
...  

The Mediterranean is an area where the balance between water demand and abstractions vs. water availability is often under stress already, as demonstrated here with the Water Exploitation Index. In this work, model estimates on how different proposed measures for water resources management would affect different indicators. After a review of the current water resources status in the Mediterranean and the definition of indicators used in this study, aspects interlinked with water in the Water-Energy-Food-Ecosystems Nexus are briefly discussed, focusing on problems linked with water scarcity and depletion of groundwater resources as well as with climate change projections. Subsequently, the proposed measures for water efficiency are detailed—irrigation efficiency, urban water efficiency, water reuse and desalination—that might be effective to reduce the growing water scarcity problems in the Mediterranean. Their effects that result from the LISFLOOD model, show that wastewater reuse, desalination and water supply leakage reduction lead to decreased abstractions, but do not affect net water consumption. Increased irrigation efficiency does decrease consumption and reduces abstractions as well. We deduct however that the current envisaged water efficiency measures might not be sufficient to keep up with the pace of diminishing water availability due to climate change. More ambition is needed on water efficiency in the Mediterranean to keep water scarcity at bay.

2016 ◽  
Vol 25 (2) ◽  
pp. eR02 ◽  
Author(s):  
Teresa Soares David ◽  
Clara Assunção Pinto ◽  
Nadezhda Nadezhdina ◽  
Jorge Soares David

Aim of the study: Water scarcity is the main limitation to forest growth and tree survival in the Mediterranean hot climate zone. This paper reviews literature on the relations between water and forests in the region, and their implications on forest and water resources management. The analysis is based on a hydraulic interpretation of tree functioning.Area of the study: The review covers research carried out in the Mediterranean hot climate zone, put into perspective of wider/global research on the subject. The scales of analysis range from the tree to catchment levels.Material and Methods: For literature review we used Scopus, Web of Science and Google Scholar as bibliographic databases. Data from two Quercus suber sites in Portugal were used for illustrative purposes.Main results: We identify knowledge gaps and discuss options to better adapt forest management to climate change under a tree water use/availability perspective. Forest management is also discussed within the wider context of catchment water balance: water is a constraint for biomass production, but also for other human activities such as urban supply, industry and irrigated agriculture.Research highlights: Given the scarce and variable (in space and in time) water availability in the region, further research is needed on: mapping the spatial heterogeneity of water availability to trees; adjustment of tree density to local conditions; silvicultural practices that do not damage soil properties or roots; irrigation of forest plantations in some specific areas; tree breeding. Also, a closer cooperation between forest and water managers is needed.Keywords: tree hydraulics; tree mortality; climate change; forest management; water resources.


2015 ◽  
Vol 01 (01) ◽  
pp. 1450001 ◽  
Author(s):  
Roberto Roson ◽  
Martina Sartori

We evaluate the structural consequences of water availability scenarios in the Mediterranean, following a multidisciplinary approach and a sequential modeling methodology. This includes an assessment of future water availability and a general equilibrium macroeconomic analysis of changes in agricultural productivity. Lower productivity in agriculture, induced by reduced water availability, generates negative consequences in terms of real income and welfare. The magnitude of the loss depends on the amount of the productivity shock, but also on the share of agricultural activities in the economy and on the stringency of the environmental regulation. We find evidence of a dramatic cut in the supply of water for agriculture in the Middle East. We consider alternative scenarios, differing in terms of stringency of environmental regulation and assumptions about water efficiency. The largest welfare losses turn out to be in Morocco and Tunisia, especially in the "worst" scenario NM. Other very relevant impacts can be observed in Turkey, Greece, Spain, Italy and Rest of Middle East and North Africa (XMENA). There are also clear differences among the scenarios. First, applying a constraint on the access to environmental water reserves only for Europe does make a big difference for non-European countries, implying that governments in the Middle East could respond to increasing water scarcity by accepting, to some extent, lower environmental quality (deterioration of aquatic environments). To avoid large drops in income and welfare, countries such as Tunisia and Morocco would not devote to environmental flows more than 10% and 5%, respectively, of their blue water resources. Second, improvements in water efficiency, as envisaged in the simulation exercise, appear to curb the economic impact of water scarcity quite significantly. This is especially true for countries in the North, whereas efficiency does not compensate for a strict environmental policy in the South.


2014 ◽  
Vol 18 (8) ◽  
pp. 2859-2883 ◽  
Author(s):  
M. I. Hejazi ◽  
J. Edmonds ◽  
L. Clarke ◽  
P. Kyle ◽  
E. Davies ◽  
...  

Abstract. Water scarcity conditions over the 21st century both globally and regionally are assessed in the context of climate change and climate mitigation policies, by estimating both water availability and water demand within the Global Change Assessment Model (GCAM), a leading community-integrated assessment model of energy, agriculture, climate, and water. To quantify changes in future water availability, a new gridded water-balance global hydrologic model – namely, the Global Water Availability Model (GWAM) – is developed and evaluated. Global water demands for six major demand sectors (irrigation, livestock, domestic, electricity generation, primary energy production, and manufacturing) are modeled in GCAM at the regional scale (14 geopolitical regions, 151 sub-regions) and then spatially downscaled to 0.5° × 0.5° resolution to match the scale of GWAM. Using a baseline scenario (i.e., no climate change mitigation policy) with radiative forcing reaching 8.8 W m−2 (equivalent to the SRES A1Fi emission scenario) and three climate policy scenarios with increasing mitigation stringency of 7.7, 5.5, and 4.2 W m−2 (equivalent to the SRES A2, B2, and B1 emission scenarios, respectively), we investigate the effects of emission mitigation policies on water scarcity. Two carbon tax regimes (a universal carbon tax (UCT) which includes land use change emissions, and a fossil fuel and industrial emissions carbon tax (FFICT) which excludes land use change emissions) are analyzed. The baseline scenario results in more than half of the world population living under extreme water scarcity by the end of the 21st century. Additionally, in years 2050 and 2095, 36% (28%) and 44% (39%) of the global population, respectively, is projected to live in grid cells (in basins) that will experience greater water demands than the amount of available water in a year (i.e., the water scarcity index (WSI) > 1.0). When comparing the climate policy scenarios to the baseline scenario while maintaining the same baseline socioeconomic assumptions, water scarcity declines under a UCT mitigation policy but increases with a FFICT mitigation scenario by the year 2095, particularly with more stringent climate mitigation targets. Under the FFICT scenario, water scarcity is projected to increase, driven by higher water demands for bio-energy crops.


2016 ◽  
Vol 113 (33) ◽  
pp. 9222-9227 ◽  
Author(s):  
Silvan Ragettli ◽  
Walter W. Immerzeel ◽  
Francesca Pellicciotti

Mountain ranges are the world’s natural water towers and provide water resources for millions of people. However, their hydrological balance and possible future changes in river flow remain poorly understood because of high meteorological variability, physical inaccessibility, and the complex interplay between climate, cryosphere, and hydrological processes. Here, we use a state-of-the art glacio-hydrological model informed by data from high-altitude observations and the latest climate change scenarios to quantify the climate change impact on water resources of two contrasting catchments vulnerable to changes in the cryosphere. The two study catchments are located in the Central Andes of Chile and in the Nepalese Himalaya in close vicinity of densely populated areas. Although both sites reveal a strong decrease in glacier area, they show a remarkably different hydrological response to projected climate change. In the Juncal catchment in Chile, runoff is likely to sharply decrease in the future and the runoff seasonality is sensitive to projected climatic changes. In the Langtang catchment in Nepal, future water availability is on the rise for decades to come with limited shifts between seasons. Owing to the high spatiotemporal resolution of the simulations and process complexity included in the modeling, the response times and the mechanisms underlying the variations in glacier area and river flow can be well constrained. The projections indicate that climate change adaptation in Central Chile should focus on dealing with a reduction in water availability, whereas in Nepal preparedness for flood extremes should be the policy priority.


2021 ◽  
Author(s):  
Ronan Abhervé ◽  
Clément Roques ◽  
Laurent Longuevergne ◽  
Stéphane Louaisil ◽  
Jean-Raynald de Dreuzy ◽  
...  

<p>While it is well understood and accepted that climate change and growing water needs affect the availability of water resources, the identification of the main physical processes involved remains challenging. It notably requires to filter interannual to interdecadal fluctuations and extreme events to isolate the underlying trends. Metropolitan areas are specifically subject to growing pressures because of the significant and increasing demand, combined with the strong anthropization of land uses.</p><p>The Meu-Chèze-Canut catchment supplies the city of Rennes with drinking water (680 km² - 500 000 users, Brittany, France). In this field laboratory, we explore the dynamics of the water cycle and water resources availability. In this context, water supply is mostly coming from reservoir storage for which levels shows a medium-term vulnerability in response to frequent relatively dry years. Based on retrospective data analysis, we describe the relationship between climatic forcing (precipitation, temperature) and water availability (aquifer storage, river discharge and reservoir storage) in different parts of the catchment that are characterized by distinct lithological and topographical settings. We then evaluate the resilience of both surface and groundwater resources, their past evolution and their resilience to climate change and increasing societal needs.</p><p>Water resources availability in these catchments relies on two geological formations with distinct hydrodynamics properties: the Armorican sandstone and Brioverian schist. To assess the resilience of the system, we specifically analyzed the relationships between monthly effective precipitation and stream discharge within nine sub-catchments over the past 30 years. We observe annual hysteresis relationships - that is, a time lag between precipitation and discharge highlighting the capacity of the landscape to temporarily store water - with significant variability in shapes across the catchments. We argue that topographic and lithological factors play key roles in controlling this variability through their impacts on subsurface storage capacity and characteristic drainage timescales. We propose perspectives based on the complementary use of calibrated groundwater models to leverage these results and provide adaptive water management strategies.</p>


Author(s):  
Nilanjan Ghosh ◽  
Anandajit Goswami

This chapter presents the concept of the establishment of a futures market in water in the context of the risk of water availability that Indian agriculture has been facing in the recent years. In the process, the chapter argues how the development of such a market can actually reduce the scarcity value of water, and may help in reducing the intensity of conflicts over water resources.


polemica ◽  
2018 ◽  
Vol 18 (2) ◽  
pp. 072-086
Author(s):  
Sandra Sereide Ferreira da Silva ◽  
Vera Lúcia Antunes De Lima ◽  
Ângela Maria Cavalcanti Ramalho ◽  
Allan Carlos Alves

Resumo: A escassez da água em regiões áridas e semiáridas tem sido tema de debates, políticas e pesquisas com o objetivo principal de subsidiar as ações capazes de permitir o seu aproveitamento racional, permitindo a convivência da população com os períodos de seca ou reduzida precipitação. Assim, a escassez de água tem conduzido à implantação de projetos de desenvolvimento, que têm como desafio a busca de alternativas de convivência com a seca que conduzam a melhorias sociais. Com base nesse contexto, este estudo tem como objetivo propor a criação de um modelo de construção de cenários para viabilidade do reúso de água para ser utilizado como elemento mitigador das implicações da seca em regiões semiáridas. O modelo de construção de cenários é um importante instrumento de gerenciamento de recursos naturais, neste caso específico, recursos hídricos, pois permite envolver um grande número de participantes, tem a possibilidade de orientar o debate público para a construção estratégica coletiva de um futuro almejado, contribui para um eficaz processo de aprendizagem organizacional no âmbito do Sistema Nacional de Gerenciamento de Recursos Hídricos visando um melhor entendimento, tanto dos aspectos ambientais quanto dos aspectos sociais e institucionais relacionados aos recursos hídricos no País, em especial, nas regiões semiáridas. Como se trabalham e convivem com a incerteza, os cenários procuram analisar e sistematizar as diversas probabilidades dos eventos e dos processos por meio da exploração dos pontos de mudança e das grandes tendências, de modo que as alternativas mais prováveis sejam antecipadas.Palavras-chaves: Recursos Hídricos. Reúso de Água. Regiões Semiáridas. Construção de Cenários.Abstract: Water scarcity in arid and semi-arid regions has been the subject of debates, policies and research with the main objective of subsidizing actions capable of allowing their rational use, allowing the population to coexist with periods of drought or reduced precipitation. Thus, water scarcity has led to the implementation of development projects, which challenge the search for alternatives to coexistence with drought that lead to social improvements. Based on this context, this study aims to propose the creation of a model for the construction of scenarios for the feasibility of water reuse to be used as a mitigating element of the drought implications in semi-arid regions. The scenario building model is an important tool for managing natural resources, in this specific case, water resources, since it allows a large number of participants to be involved, it has the possibility of guiding the public debate towards the collective strategic construction of a desired future, contributes to an effective organizational learning process within the National Water Resources Management System aiming at a better understanding of both the environmental aspects and the social and institutional aspects related to the water resources in the Country, especially in the semi-arid regions. As they work and coexist with uncertainty, the scenarios seek to analyze and systematize the various probabilities of events and processes by exploring the points of change and the major trends, so that the most likely alternatives are anticipated.Keywords: Water Resources. Water reuse. Semi-Arid Regions. Construction of Scenarios.


Atmosphere ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 593 ◽  
Author(s):  
Ertug Ercin ◽  
Daniel Chico ◽  
Ashok K. Chapagain

Climate change is leading to increased water scarcity and drought in many parts of the world. This has implications for the European Union (EU) because a lot of the water intensive goods consumed or used there are produced abroad. This makes the EU’s economy dependent on water resources well beyond its borders since when a country imports water intensive goods, indirectly it also imports virtual water (water needed to produce the imported goods). This study maps the EU’s global dependency on water resources outside its borders in terms of virtual water imports and assesses how water scarcity and drought may disrupt supplies of key food crops that it imports. The EU uses approximately 668 km3 of water for all of the goods it produces, consumes and exports, annually. Around 38% of that water comes from outside its borders, which means that the EU’s economy is highly dependent on the availability of water in other parts of the world. In the near future, supplies of certain crops to the EU could be disrupted due to water scarcity in other parts of the world; a large portion of the water used in producing soybeans, rice, sugarcane, cotton, almonds, pistachios and grapes for import to the EU comes from areas with significant or severe levels of water scarcity. Although the immediate risks to the EU’s economy are due to current water scarcity levels, any disruption to rainfall patterns that occur in the future, due to the effects of climate change in the countries of origin of key crops, could have a far greater impact. This is because as much as 92% of the EU’s total external water demand from agriculture is attributed to green water use, availability of which has relatively higher vulnerability to drought.


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