Water for people.pdf - WHO Thailand Digital Repository

1 4 / S E T T I N G T H E S C E N EThe World’s Water CrisisAdditionally, modern hydropower plants increasingly provide majorbenefits to local populations. Hydro is also, relative to other formsof major energy production, environmentally benign. As waterscarcity increases these facilities will increasingly become the focusof attention.Substantial amounts of water are used for cooling and inchemical processes. The majority is returned to the watershed, withrelatively little loss to contamination or evaporation, though thechange of temperature can have important ecological consequences,which are discussed in chapter 10.UrbanizationIn addition to general population growth, the changingdemographics are affecting how water resources are managed. Atthe beginning of the twentieth century, only a small percentage ofthe population lived in cities in most regions of the world, but asthe world population has increased, so has the proportion that livein urban areas. The urban population rose greatly throughout thetwentieth century and is projected to reach 58 percent of the worldpopulation by 2025 (UNFPA, 2002). In the next thirty years, thegreatest urban growth will occur in Asia (see figure 1.3). UN (2002)estimates show that in real terms the urban population of the lessdeveloped world is expected to nearly double in size between 2000and 2030 from a little under 2 billion to nearly 4 billion people (seefigure 1.4). Between 2015 and 2020, urban population will exceedrural for the first time, and will continue to escalate sharply whilerural numbers remain more or less static.As the population in these centres grow, so do their demandsfor resources; reflecting both the high concentrations of people andthe very different lifestyles and aspirations of city dwellers. Amongthe consequences of this urban influx are the overloading of watersupply and sanitation infrastructure – a situation made worse by thegeographical location of some of these cities. The problems ofwater supply have forced many urban authorities to over-exploitfragile sources, such as aquifers, and there are many examples offalling water levels in many cities (e.g. in Manila in the Philippines).Deterioration of water supplies and sanitation leads to a progressivedecline in urban living conditions – water shortages, pollution andunsanitary water conditions all of which contribute to an urbanwater and health crisis. Many poor people in cities also pay veryhigh prices for their water from private vendors, and agitation andeven riots over poor water supplies (especially during droughts) arefar from unknown. Inadequate coverage and decline in urbaninfrastructure hits the poorest hardest as wealthier households tendto have access to urban water supplies or can afford tubewells ifthe supply is unreliable or of poor quality.Figure 1.3: Actual and projected urban population in differentregions of the world in 1950, 2000 and 2030PopulationMillions1,0008006004002000East AsiaNorth AmericaSource: UN, 2000.Figure 1.4: Urban and rural population, less developedcountries, 1950–20304,000,0003,500,0003,000,0002,500,0002,000,0001,500,0001,000,000500,00001950 1960 1970 1980 1990 2000 2010 2020 2030YearUrbanRuralThe urban population rose greatly throughout the twentieth century and is projectedto reach 58 percent of the world population by 2025. Meanwhile, the ruralpopulation is expected to stabilize from 2010.Source: UN, 2000.West EuropeEast EuropeSouth-central AsiaNorth EuropeSouth AmericaSouth EuropeSouth-eastern Asia195020002030Central AmericaWest AsiaNorth AfricaAustralia/N. ZealandWest AfricaCaribbeanSouthern AfricaMid-AfricaEastern AfricaMela, Poly, & Micronesia