Knowledge journal / Edition 1 / 2016

What effect does production have on the availability of fresh water?

Worldwide, fresh water is becoming increasingly scarce. In some regions it is scarcer than in others. How do you focus on the impact of products and production processes on the availability of fresh water? The Dutch ReCiPe model is a life cycle impact model used to gain insight in environmental effects, including the use of water.

Environment focused life cycle assessment (LCA) is a method used to map the influence of products and services on the environment. From the extraction of raw materials through production, processing and (re)use to waste and waste treatment. It is expected that these approaches are going to play an increasingly important role in assessing the sustainability of products.

Within the LCA, environmental models (life-cycle impact models; LCIA models) are used to calculate what the impact on the environment will be of all emissions and uses (of materials and energy) in the entire life cycle of a product.
The ReCiPe model developed in the Netherlands is a well known and commonly used LCIA method world-wide. In this model, environmental effects are assessed on two levels: midpoint and endpoint. Midpoints indicate the contribution of a product to a specific environmental impact. Examples of midpoints are climate change and acidification. Endpoints are defined as the final damage to the natural environment (biodiversity), human health and raw material exhaustion, which are caused by the various environmental effects at midpoint level.

Figure 1 provides a schematic picture of the life cycle of a product and the way in which an environmental damage calculation can be conducted on it. The stages in LCA research are visualised from left to right, with a final impact calculation in ReCiPe on both midpoint and endpoint level.


Figure 1. Schematic representation of the life cycle of a product and the way in which an environmental damage calculation can be conducted on this using LCA. The stages in LCA research are visualized from left to right, with a final impact calculation in ReCiPe on both midpoint and endpoint level

Environmental impact on water consumption

A new version of the ReCiPe model will be published in 2016, in which the determination of the damage of fresh water consumption on biodiversity (soil and fresh water) and human health is quantified spatially. The environmental impact of water consumption is determined both at midpoint (water consumption) and at endpoint level (damage to the ecosystems and human health; see Figure 2).


Figure 2. Cause-effect chain of water consumption as implemented in ReCiPe for 2015

The midpoint factor unit is the number of cubic meters of water consumed per number of cubic meters water extracted, and reflects the relative loss of water by evaporation or incorporation in products.
Modelling of the different types of damage always starts with quantification of the reduction of the availability of fresh water. Damage to people is then caused by the competition between water consumption for irrigation and for other purposes. Shortage of irrigation eventually leads to lack of food for local populations and eventual loss in years of life. Damage to ecosystems on land is quantified as a loss of species due to the effect of water shortages on net bio-productivity, while damage to freshwater ecosystems is quantified on the basis of the relationship between the number of freshwater fish species and the drainage of rivers. 
The calculations were performed for individual countries to take into account the fact that the influence of water consumption in water-rich countries can turn out quite different from that in countries lacking water.

Midpoint and endpoint factors

The ultimate impact on the life cycle of a product as a result of water consumption is the sum of the consumed water (difference between extracted water and water being discharged again) over all processes that play a role in the life cycle of a product, weighted with midpoint factors or endpoint factors:


- WEi,j represents the water extraction in process i of the life cycle (for example, irrigation of grain) in country j, (cubic meters extracted water).
- MFi,j is the midpoint factor for water extraction in process i in country j (cubic meters of water consumed per cubic meters water extracted).
- EFj,e is the mid-to-endpoint factor for water consumption in country j for endpoint e (for example, loss of years of life per cubic metre of consumed water).

Based on this calculation method, the so-called water requirement ratio was pinpointed per country: the ratio between the amount of water consumed and the amount of extracted water for agricultural purposes. Figure 3 indicates that the consumption fraction of water extracted for agricultural purposes varies markedly between countries. This is because there are huge differences in the efficiency of irrigation systems between countries. Irrigation is implemented very effectively in industrialised countries, whereas much water is often lost in developing countries.


Figure 3. Midpoint factors (consumed in m3/extracted in m3) for agricultural purposes

When performing a LCA on an agricultural product, it is therefore important to look at the country of origin of the water consumption. The midpoint level calculation is therefore based on the amount of water extracted for a particular process, multiplied by the water requirement ratio and totalled over all processes that are relevant to the life cycle of a product (see also the formula above). This gives the total quantity of actually consumed water over the life cycle of a product.

Figure 4 reflects the characterisation factors (CF) per country for human health represented as loss in years of life per cubic meters of water consumption. Endpoints are calculated on this basis, in this case for health. In some rich countries (including the US, Canada, Australia and countries in Europe) the loss of years of life is zero. These countries have water in abundance. For relatively poor countries, such as India and the countries of the Sahel, the loss of years of life per cubic meter water is relatively high (6 years loss per million cubic meters).


Figure 4. Chart with characterisation factors by country for human health and loss in years of life per m3 of water consumption

Discussion

Of course, the described method is not perfect. LCA methods must be suitable for describing all the steps in the life cycle for a very wide range of products and services. In addition, a large number of environmental aspects are rated next to each other in a LCA study, and the methods must also be suitable for environmental assessments on a global scale.
The methods used give a strongly simplified view of reality. In addition, due to lack of data, assumptions must also be made. For instance, for the environmental aspect of water scarcity, the physic-geographical differences on a local scale, such as soil conditions and availability of groundwater bodies, weren't considered at all. For location-specific issues, it is therefore always better to base the analysis on local conditions. However, LCA gives good insight into the expected environmental effects of a particular activity for issues on a global scale and to assess chains.

In practice

Large-scale shortage of fresh water is a global problem, especially rampant in developing countries. Although it seems far from home, we in the Netherlands are directly involved through food production chains, for example.
Although the methodology described here represents a pretty rough approach, we can generate quite a clear picture of the effects of the consumption of goods here on water problems elsewhere in the world. For example by importing green beans from Senegal, you indirectly import water from an area where it is a scarce commodity. More than 1000 litres of water is required for the production of a cotton T-shirt in cotton cultivation and in the industrial production process. With the T-shirt, we in fact import precious water from areas where this is scarce.

Raising awareness on the effect of the consumption of food and goods from water poor areas, only grow slowly among Dutch consumers. To increase that awareness, government and commerce will have to play a role. Unlocking knowledge on production chains (where does what come from?) and the clever combination of knowledge on water management and LCA can help to better support the global information supply involving fresh water supplies and fresh water scarcity issues.
Comparable methods for this are the 'water footprint' (www.waterfootprint.org), specifically the 'blue water footprint', or the 'water pricing' method: assigning a monetary value to water consumption based on scarcity indicators (among others www.oecd.org). Although our calculation method is different from for instance those of the water footprint, the approach is similar, and both methods serve to assess the impact of our consumption of products and services on the water problems of the world.

Anne Hollander
(RIVM)
Mark Huijbregts
(Radboud University Nijmegen)
Michiel Zijp
(RIVM)
Francesca Verones
(Department of Energy and Process Engineering, Norway)

Literature

Goedkoop, M., Heijungs, R., Huijbregts, M. A. J., De Schryver, A., Struijs, J. and van Zelm, R. (2009). ReCiPe 2008: A life cycle impact assessment method which comprises harmonised category indicators at the midpoint and endpoint levels. First edition. Report i: Characterization. The Netherlands, Ruimte en Milieu, Ministerie van Volkshuisvesting, Ruimtelijke Ordening en Milieubeheer.

Huijbregts, M.A.J, Steinman Z.J.N., Elshout P.M.F., Stam G., Verones, F., Vierra M., Van Zelm, R., 2015. ReCiPe 2015: A harmonized life cycle impact assessment method at midpoint and endpoint level. Report I: Characterization. . Department of Environmental Science. Radboud University Nijmegen.

Pfister, S., Koehler, A. and Hellweg, S. (2009). Assessing the Environmental Impacts of Freshwater Consumption in LCA. Environ. Sci. Technol. 43(11): 4098-4104.

De Schryver, A. M., Van Zelm, R., Humbert, S., Pfister, S., McKone, T. E. and Huijbregts, M. A. J.(2011). Value Choices in Life Cycle Impact Assessment of Stressors Causing Human Health Damage. Journal of Industrial Ecology 15(5): 796-815.

Hanafiah, M. M., Xenopoulos, M. A., Pfister, S., Leuven, R. S. and Huijbregts, M. A. J. (2011). Characterization Factors for Water Consumption and Greenhouse Gas Emissions Based on Freshwater Fish Species Extinction. Environ. Sci. Technol. 45(12): 5572-5278.

Auteurs

Anne Hollander
(RIVM)

Mark Huibregts
(Radboud University Nijmegen)

Michiel Zijp
(RIVM)

Francesca Verones
(Department of Energy and Process Engineering, Norway)