“Water supply and flood management, ranks as one of the top three climate adaptation costs in both the wetter and drier scenario, with Sub-Saharan Africa footing by far the highest costs” says a new World Bank report.
The draft global report of the Economics of Adaptation to Climate Change Study (EACC) calculates the cost between 2010 and 2050 of adapting to an approximately 2°C warmer world by 2050. A second report due in March 2010 will consist of seven country case studies (Bangladesh, Bolivia, Ethiopia, Ghana, Mozambique, Samoa, and Viet Nam).
The EACC study estimates that over the next 40 years, global net annual adapation costs for municipal and industrial water supply will be between US$ 10.0 billion (wetter scenario) and US$ 11.1 billion (dry scenario). In both scenarios, nearly two-thirds of these costs (US$ 5.9 billion and US$ 7.3 billion, respectively) are for Sub-Saharan Africa [tab. 13, p. 54].
“Costs of adaptation are defined as the cost of providing enough raw water to restore future industrial and municipal water demand to the levels that would have existed without climate change. Such demand is assumed to be met by increasing the capacity of surface reservoir storage, except when that would raise withdrawals to more than 80 percent of river runoff and when the cost of supplying water from reservoir yield is more than $0.30 a cubic meter. In these cases, supply is assumed to be met through alternative measures, such as recycling, rainwater harvesting, and desalination, at a cost of $0.30 a cubic meter” [p. 53].
The adaptation cost for water supply and flood management in the EACC study is higher than previously calculated by United Nations Framework Convention on Climate Change (UNFCC) in 2007. The World Bank says this is because it has tried to include a number of costs that UNFCC overlooked, such as the costs of maintaining water quality standards and operating costs [p. 82-83].
“As do most sectoral studies of global adaptation costs, [EACC] study focuses on hard adaptation measures, which are easier to cost than behavioral measures. There is no implication that these are the best measures for adaptation. Ideally, adaptation options to ensure water supply during average and drought conditions should integrate strategies on both demand and supply sides. While demand-side adaptations are not explicitly costed in this study (demand projections already account for some increase in efficiencies over time, so this could lead to double counting), there is wide scope for economizing on water consumption” [p. 55].
Global adapation costs for water supply and sanitation infrastructure were estimated to be US$ 700 million per year [tab. 8, p. 44].
Average annual adaptation costs in the health sector for diarrhoea and malaria prevention and treatment lie in a narrow range of US$ 1.3–1.6 billion a year over the 40-year period 2010–50, according to the EACC study. These estimates for malaria and diarrhea are lower than the prior estimates of US$ 4–12 billion, because they take into account the effects of development and the resulting decline in under-five mortality [p. 66-68].
Though adaptation is costly, costs can be reduced, says the World Bank. “The clearest opportunities to reduce the costs of adaptation are in the water supply and flood protection sector. [...] A large share of the costs of adaptation in the water supply and flood protection sector could be avoided by adopting better management [and water tariff] policies” [p. 94-95].
One important lesson that the report mentions is that “development is the most powerful form of adaptation”. It suggests too that the costs of adaptation may also be dramatically reduced by a combination of technical change and private initiative.
For more information see the World Bank EACC home page