D. Vanham

Potential water saving through changes in European diets.

This study quantifies the water footprint of consumption (WFcons) regarding agricultural products for three diets - the current diet (REF), a healthy diet (HEALTHY) and a vegetarian diet (VEG) - for the four EU zones WEST, NORTH, SOUTH and EAST. The WFcons related to the consumption of agricultural products (4265l per capita per day or lcd) accounts for 89% of the EUs total WFcons (4815lcd). The effect of diet has therefore an essential impact on the total WFcons. The current zonal WFcons regarding agricultural products is: 5875lcd (SOUTH), 4053lcd (EAST), 3761lcd (WEST) and 3197lcd (NORTH). These differences are the result of different consumption behaviours as well as different agricultural production methods and conditions. From the perspective of a healthy diet based on regional dietary guidelines, the intake of several product groups (sugar, crop oils, animal fats and meat) should be decreased and increased for others (vegetables, fruit). The WFcons regarding agricultural products for the alternative diets are the following: HEALTHY 4110lcd (-30%) and VEG 3476lcd (-41%) for SOUTH; HEALTHY 3606lcd (-11%) and VEG 2956lcd (-27%) for EAST; HEALTHY 2766lcd (-26%) and VEG 2208lcd (-41%) for WEST; HEALTHY 3091lcd (-3%) and VEG 2166lcd (-32%) for NORTH. Both the healthy and vegetarian diets thus result - consistent for all zones - in substantial WFcons reductions. The largest reduction takes place for the vegetarian diet. Indeed, a lot of water can be saved by EU citizens by a change in their diet.

The water footprint of Austria for different diets

This paper analyses the Austrian water footprint of consumption (WF(cons)) for different diets: the current diet, a healthy diet (based upon the dietary recommendations issued by the German nutrition society, or DGE), a vegetarian diet and a combined diet between both latter diets. As in many western countries, the current Austrian diet consists of too many products from the groups sugar, crop oils, meat, animal fats, milk, milk products and eggs and not enough products from the groups cereals, rice, potatoes, vegetables and fruit. Especially the consumption of animal products accounts for high WF amounts. These diets result in a substantial reduction (range 922-1,362 l per capita per day (lcd)) of the WF(cons) for agricultural products, which is currently 3,655 lcd. However, the Austrian water footprint of agricultural production (WF(prod) = 2,066 lcd) still remains lower than even the WF(cons) for a vegetarian diet (2,293 lcd). As a result the country is a net virtual water importer regarding agricultural products for all analysed scenarios.

Lost water and nitrogen resources due to EU consumer food waste

The European Parliament recently called for urgent measures to halve food waste in the EU, where consumers are responsible for a major part of total waste along the food supply chain. Due to a lack of data on national food waste statistics, uncertainty in (consumer) waste quantities (and the resulting associated quantities of natural resources) is very high, but has never been previously assessed in studies for the EU. Here we quantify: (1) EU consumer food waste, and (2) associated natural resources required for its production, in term of water and nitrogen, as well as estimating the uncertainty of these values. Total EU consumer food waste averages 123 (min 55–max 190) kg/capita annually (kg/cap/yr), i.e. 16% (min 7–max 24%) of all food reaching consumers. Almost 80%, i.e. 97 (min 45–max 153) kg/cap/yr is avoidable food waste, which is edible food not consumed. We have calculated the water and nitrogen (N) resources associated with avoidable food waste. The associated blue water footprint (WF) (the consumption of surface and groundwater resources) averages 27 litre per capita per day (min 13–max 40 l/cap/d), which slightly exceeds the total blue consumptive EU municipal water use. The associated green WF (consumptive rainwater use) is 294 (min 127–max 449) l/cap/d, equivalent to the total green consumptive water use for crop production in Spain. The nitrogen (N) contained in avoidable food waste averages 0.68 (min 0.29–max 1.08) kg/cap/yr. The food production N footprint (any remaining N used in the food production process) averages 2.74 (min 1.02–max 4.65) kg/cap/yr, equivalent to the use of mineral fertiliser by the UK and Germany combined. Among all the food product groups wasted, meat accounts for the highest amounts of water and N resources, followed by wasted cereals. The results of this study provide essential insights and information on sustainable consumption and resource efficiency for both EU policies and EU consumers.

The water footprint of Milan

This study quantifies the water footprint of consumption (WFcons) and production (WFprod) of Milan. The current WFcons amounts to 6,139 l/cap/d (a volume of 2.93 km(3) annually), of which 52 l/cap/d (1%) is attributed to domestic water, 448 l/cap/d (7%) to the consumption of industrial products and 5,639 l/cap/d (92%) to the consumption of agricultural products. The WFprod is 52 l/cap/d. Milan is thus a net virtual water importer, predominantly through the import of agricultural products. These are produced outside city borders, both in Italy and abroad. This shows the dependency of city dwellers on water resources from other river basins. In addition, the WFcons for a healthy diet (based on Mediterranean Food-Based Dietary Guidelines) and a vegetarian diet are analysed. The current Milanese diet consists of too much sugar, crop oils, meat, animal fats, milk and milk products and not enough cereals, rice, potatoes, vegetables and fruit. The latter two diets result in substantial WFcons reductions: -29% (to 4,339 l/cap/d) for a healthy diet and -41% (to 3,631 l/cap/d) for a vegetarian diet. Indeed, a lot of water could be saved by Milan citizens through a change in their diet. A sustainable city should account for its impacts beyond its borders.

To what extent does climate change result in a shift in Alpine hydrology? A case study in the Austrian Alps

Abstract The quantification of the effect of climate change on the hydrological water balance components within a catchment is invaluable for future planning within the water sector (municipal and industrial water supply, hydropower, irrigation, snowmaking). As the regional effect of global warming is somewhat uncertain, the provision of quantitative estimates with error bands is essential. Many studies only take one or a very limited sample of climate change scenarios into account. In this paper, the hydrological response to a number of regional climate change model scenarios for the end of the 21st century within the catchment of the Kitzbüheler Ache in Austria is investigated by means of a distributed hydrological model. These regional climate scenarios originate from the European PRUDENCE project. The results show a shift from a rainfall and snowmelt-dominated flow regime to a rainfall-dominated flow regime for all scenarios. A future decrease in snowmelt and a shortening in snow cover duration is observed, with an increase in winter flow, and a decrease in spring, summer and autumn flow. The typical low-flow period during winter shifts to a low-flow period during late summer and autumn. However, the magnitude of the effects depends strongly on the choice of scenario. Average annual snowmelt reduction ranges from 31 to 81%, average annual runoff reduction from 6 to 33% and average annual evapotranspiration increase from 6 to 20%. These uncertainties are also presented for a monthly and a seasonal time step. These values and observations provide for a future vision within a mountainous catchment in the European Alps. Normal future planning is within a shorter time frame (20–30 years within the water sector), but this future vision puts realistic planning in a wider context. Editor Z.W. Kundzewicz; Associate editor R.L. Wilby Citation Laghari, A.N, Vanham, D. and Rauch, W., 2012. To what extent does climate change result in a shift in Alpine hydrology? A case study in the Austrian Alps. Hydrological Sciences Journal, 57 (1), 103–117.

Impact of snowmaking on alpine water resources management under present and climate change conditions.

Owing to less natural snow reliability as a result of climate change on the one hand, and the demand of higher standards by winter tourists on the other hand, the production of artificial snow in ski resorts has increased substantially during the last 20 years and is likely to increase further in future. Little research has been conducted on the impact of snowmaking as a water demand stakeholder on a regional water balance. In this paper, a regional water balance (water demand-water resources) is analysed for the greater Kitzbueheler Region in the Austrian Alps, for the current situation and a future climate change scenario (2 degrees C warming). For this temperature rise a significant reduction in natural snow cover duration and snow accumulation is predicted, an effect that increases with lower altitudes and differs between the winter months. Due to the shortening of the winter season, a change in seasonality of river flows and available water resources (ground and surface water) occurs. Both increase in winter, and decrease in spring. The water demand for improvement snowmaking increases, especially in the month of March. However, December proved to be the critical month due to the large amounts of water required for base snowmaking both now and in future. These results stress the necessity of reservoir storage for base snowmaking on a regional level. Water availability during other months but winter is sufficient to fill these reservoirs.

Water consumption related to different diets in Mediterranean cities.

Providing the sustainable development goals (SDGs) water, food and energy security to cities relies strongly on resource use outside city borders. Many modern cities have recently invested in a sustainable urban water system, and score high in international city rankings regarding water management and direct urban water use. However, these rankings generally neglect external resource use for cities. Here we quantify the water resources related to food consumption in thirteen cities located in Mediterranean countries, by means of the water footprint (WF) concept. These WFs amount from 3277l per capita per day (l/cap/d) to 5789l/cap/d. These amounts are about thirty times higher than their direct urban water use. We additionally analyse the WF of three diet scenarios, based upon a Mediterranean dietary pattern. Many authors identify the Mediterranean diet as cultural heritage, being beneficial for human health and a model for a sustainable food system. The first diet scenario, a healthy Mediterranean diet including meat, leads to WF reductions of -19% to -43%. The second diet scenario (pesco-vegetarian), leads to WF reductions of -28% to -52%. The third diet scenario (vegetarian), leads to WF reductions of -30% to -53%. In other words, if urban citizens want to save water, they need to look at their diets.

The water footprint of agricultural products in European river basins

This work quantifies the agricultural water footprint (WF) of production (WFprod, agr) and consumption (WFcons, agr) and the resulting net virtual water import (netVWi, agr) of 365 European river basins for a reference period (REF, 1996–2005) and two diet scenarios (a healthy diet based upon food-based dietary guidelines (HEALTHY) and a vegetarian (VEG) diet). In addition to total (tot) amounts, a differentiation is also made between the green (gn), blue (bl) and grey (gy) components. River basins where the REF WFcons, agr, tot exceeds the WFprod, agr, tot (resulting in positive netVWi, agr, tot values), are found along the London–Milan axis. These include the Thames, Scheldt, Meuse, Seine, Rhine and Po basins. River basins where the WFprod, agr, tot exceeds the WFcons, agr, tot are found in Western France, the Iberian Peninsula and the Baltic region. These include the Loire, Ebro and Nemunas basins. Under the HEALTHY diet scenario, the WFcons, agr, tot of most river basins decreases (max �32%), although it was found to increase in some basins in northern and eastern Europe. This results in 22 river basins, including the Danube, shifting from being net VW importers to being net VW exporters. A reduction (max �46%) in WFcons, agr, tot is observed for all but one river basin under the VEG diet scenario. In total, 50 river basins shift from being net VW importers to being net exporters, including the Danube, Seine, Rhone and Elbe basins. Similar observations are made when only the gn+bl and gn components are assessed. When analysing only the bl component, a different river basin pattern is observed. S Online supplementary data available from stacks.iop.org/ERL/9/064007/mmedia

A holistic water balance of Austria – how does the quantitative proportion of urban water requirements relate to other users?

Traditional water use statistics only include the blue water withdrawal/consumption of municipalities, industry and irrigated agriculture. When, however, green water use of the agricultural sector is included as well as the virtual water use/water footprint (WF), water use quantity statistics become very different. In common water use statistics, Austria withdraws in total about 2.5 km(3) per year, only 3% of available resources (total discharge 81.4 km(3) = surface and ground water). The total water consumption (0.5 km(3)) is less than 1% of available resources. Urban (municipal) water requirements account for 27% of total withdrawal or 33% of consumption. When agricultural green water use (cropland) is included in statistics, the fraction of municipal water requirements diminishes to 7.6% of total withdrawal and 2.5% of total consumption. If the evapotranspiration of grassland and alpine meadows is also included in agricultural green water use, this fraction decreases to 3.2% and 0.9% respectively. When the WF is assessed as base value for water use in Austria, the municipal water use represents 5.8% of this value. In this globalized world, these traditional water use statistics are no longer recommendable. Only a holistic water balance approach really represents water use statistics.

Urban food consumption and associated water resources: The example of Dutch cities

Full self-sufficiency in cities is a major concern. Cities import resources for food, water and energy security. They are however key to global sustainability, as they concentrate a rapidly increasing and urbanising population (or number of consumers). In this paper, we analysed the dependency of urban inhabitants on the resource water for food consumption, by means of Dutch cities. We found that in extremely urbanised municipalities like Amsterdam and Rotterdam, people eat more meat and cereals and less potatoes than in other Dutch municipalities. Their current water footprint (WF) related to food consumption is therefore higher (3245l/cap/day) than in strongly urbanised cities (3126l/cap/day). Dutch urban citizens who eat too many animal products, crop oils and sugar can reduce their WF (with 29 to 32%) by shifting to a healthier diet. Recommended less meat consumption has the largest impact on the total WF reduction. A shift to a pesco-vegetarian or vegetarian diet would require even less water resources, where the WF can be reduced by 36 to 39% and 40 to 42% respectively. Dutch cities such as Amsterdam have always scored very high in international sustainability rankings for cities, partly due to a long history in integrated (urban) water management in the Netherlands. We argue that such existing rankings only show a certain - undoubtedly very important - part of urban environmental sustainability. To communicate the full picture to citizens, stakeholders and policy makers, indicators on external resource usage need to be employed. The fact that external resource dependency can be altered through changing dietary behaviour should be communicated.