Water for people.pdf - WHO Thailand Digital Repository

3 6 / S E T T I N G T H E S C E N ESigning Progress: Indicators Mark the Wayrisks? A simple indicator-based response to this question is that in1998, 2.2 million people died from diarrhoeal diseases of which1.8 million were children under five years of age. The statementclearly demonstrates that poor access to water and sanitationprimarily affects children under five years of age since this agegroup represents almost 85 percent of total deaths. The indicatorresponse also demonstrates, however, the risks of simplification,because it overlooks the fact that a large proportion of diarrhoealdiseases are food-borne rather than linked to contaminateddrinking water.■ Assessment: an indicator value can also be compared to areference condition that represents some desired state. Specificationof a reference condition depends strongly on the purpose of theindicator, its users, and the issue being reflected. Referenceconditions include policy targets, sustainability criteria and historicalstates. Box 3.2 demonstrates that existence of a certain mammal,fish or bird species can be a simple reference indicator to assess thequality of the ecosystem.■ Predicting the future: when models are linked to indicators, atime series can be extended into an (estimated) future.Alternative scenarios can be assessed in terms of how well eachone moves the system towards a desired state. Figure 3.4 showsan example of this use.Box 3.2: Use of species as indicators forecosystem qualitySpecies can be very good indicators for ecosystem quality. Inthe first place, the presence of a certain species providesinformation on ecological processes. For example, theoccurrence of migrating fish indicates that a river can besafely navigated by fish. Mammals are species from thehigher levels of the food chain. Their presence indicates thatthe underlying food web is functioning well enough toprovide the mammal with sufficient food. Furthermore, theyneed relatively large areas of suitable habitat. Therefore, thepresence of mammals is an indicator for the quality and sizeof an ecosystem.Beyond their face value, species serve a function ofcommunication as well, particularly species of the highertrophic levels, such as fish, mammals and birds that appeal tothe public. Therefore, the return of a popular species is oftenstated as an objective of ecological restoration measures toincrease social acceptance of these measures (e.g. salmon inthe Rhine, beaver in the Elbe).Figure 3.3: Development of consumable fish as a percentage of theminimum biomass needed for a sustainable renewal of the fish populationFigure 3.4: Annual freshwater demand in different regions of the world forthe current situation and for two alternative projections for the year 20251.81.61.41.21.00.80.60.40.20Safe biological minimumPlaiceHerring198719881989199019911992199319941995199619971998199920002001This indicator gives information on both the condition of the aquatic ecosystem and thelong-term viability of the fisheries sector. There was a trend of rapid decline in thedevelopment of consumable fish in the early 1990s, but their populations have beensteadily increasing again since 1997.Source: CIW, 2000.Cod1,000 m 3 /cap/year2.521.510.50WorldCanadaUnited StatesCentral AmericaCurrent situationProjection (2025a)Projection (2025b)South AmericaAfricaOECDEEUEx-USSRMiddle East AsiaSouth AsiaEast AsiaSouth-East AsiaOceaniaJapanThis graph represents the indicator of future annual freshwater demand. Projectionsshow that demand is likely to rise in most areas of the world, excluding Africa.Indicators can therefore be used to make projections into a possible future.Source: Watermodel, presented at the Second World Water Forum.