The 21st Century climate challenge

must take into account the impact of futureclimate change on water availability.Beyond irrigation there are wider opportunitiesto develop water harvesting, especiallyin countries—such as Ethiopia, Kenya andTanzania—with relatively abundant, butconcentrated rainfall. 39 Ethiopia spans 12major river basins and has relatively abundantwater, but one of the lowest reservoir storagecapacities in the world: 50 cubic metres perperson compared with 4,700 in Australia. Incountries lacking water storage capacity, evenincreased rainfall may not enhance water availability.High levels of runoff and increased risksof flooding are more likely outcomes.Experience from India is instructive. Here,as elsewhere, climate change will place additionalpressures on already highly stressed watersystems. While overall rainfall is projected toincrease on average, much of the country willreceive less rain. Local communities are alreadydeveloping innovative responses to water stress.Box 4.1Adaptation on the char islands of BangladeshRiver deltas in Bangladesh are on the front line of climate change.Located in the Ganges–Brahmaputra Delta, islands and other lowlyingdelta lands—known as chars—are home to over 2.5 millionhighly vulnerable people living under risk of frequent flooding. Thehuman development imperative to help such communities adaptto the increased threats brought about by climate change haslong been recognized. But innovative cost–benefi t exercises areshowing that it makes economic sense too.The lives of char people are closely bound up with the fl owof rivers—and with flooding. Chars themselves undergo constanterosion and reformation, as rivers wash away soil and deposit silt.Entire islands are vulnerable to erosion and flooding, though peopleliving by unprotected river channels face special risks.Coping capacity is limited by poverty. The riverine areas ofBangladesh are marked by high levels of human deprivation. Over 80percent live in extreme poverty (see table). Indicators for nutrition, childmortality and public health are among the worst in the country. Floodingposes a constant threat. People cope by building embankments andditches around agricultural lands—and by rebuilding their homes whenthey are destroyed. Even minor floods cause high levels of damage.Major events—such as the 1998 and 2004 floods—destroy agriculturalproduction and homes on a large scale, isolating communities fromcrucial health and other public services in the process.Government, donors and local communities have developed arange of approaches for reducing vulnerability. Protecting homes hasbeen identified as a priority. Under the Chars Livelihood Programme,one pilot project aims at ‘flood-proofing’ homesteads against floodswith a one in twenty years likelihood of occurrence (most homes arecurrently vulnerable to two-year events). The objective is to constructearth platforms to accommodate homes for four households, withtrees and grass planted as a protection against soil erosion. Handpumps and basic latrines are provided to secure access to cleanwater and sanitation. So far, around 56,000 char people haveparticipated in this re-housing programme.The benefi ts for those involved are revealed in reducedexposure to flooding. But does it make economic sense to scaleup the initiative for all 2.5 million char people? Using informationSource: Dasgupta et al. 2005; DFID 2002; Tanner et al. 2007.from local people to estimate the appropriate height for raised earthplatforms, to identify the most appropriate material for limiting soilerosion and to project future damages under different climatechange scenarios, researchers have conducted cost–benefi tanalysis to assess potential returns.The results point to a strong economic case for investment.Creating the 125,000 raised platforms needed to protect all charpeople from 20-year floods would cost US$117 million. However,every US$1 of this is estimated to protect US$2–3 in assets andproduction that would otherwise be lost during fl oods. Thesefi gures understate the wider human development benefi ts. Charpeople are among the poorest in Bangladesh. It follows that lossessustained during fl oods have highly damaging implications for theirnutrition, health and education. As shown in chapter 2, losses inthese areas can trap people in long-term cycles of destitution,undermining lifelong opportunities and transmitting povertyacross generations. There is, therefore, an urgent need to supportin-country assessments of the costs and benefi ts of identifi edadaptation options, and to scale up such assessments to nationalbudgetary planning exercises directed towards the needs of thosemost vulnerable to climate change.Human deprivation on the char islandsBangladesh2005 Char Island averageExtreme poverty (%) 80 23Literacy rate (males 10 years and older, %) 29 57Literacy rate (females 10 years and older, %) 21 46Share of households suffering food insecurity (%)1 month or more 95 ..2 months or more 84 ..3 months or more 24 ..4 months or more 9 ..Source: Dasgupta et al. 2005.4Adapting to the inevitable: national action and international cooperationHUMAN DEVELOPMENT REPORT 2007/2008 177