the quantification of water security.
risks overlooking important impacts that are harder to monetize: most notably, the impacts upon the natural environment, and the social and cultural values associated with sustainable water resources management. Even with further progress in monetization, water security will continue to be a multi-attribute construct.
The methods we have used to calculate risk can doubtless be improved upon, so we expect that future assessments will generate better estimates. Nonetheless, we believe that the analysis reported here has put in place frameworks and methodology for the quantification of water security.
3.9 Summary
Water insecurity has harmful impacts on people, economies, and the natural environment. Those risks influence people directly: for example, via the health impacts of inadequate water supply and sanitation;
through reduced yields to farmers because of water scarcity; or through damage to people’s health and homes because of floods.
Water-related risks also influence people’s economic opportunities: for example, through the time required to collect water, which could be used for other productive activities. Water-related risks have impacts on production, notably in the agriculture and energy sectors. They can impact the natural environment as well, in ways that are less amenable to quantification in economic terms.
In this chapter, we have sought to quantify, as far as global datasets have allowed, the most important direct water-related risks to the economy, society, and the environment. The focus of these metrics reflects the findings of the global econometric analysis developed in Chapter 2. That analysis pointed to runoff variability (in particular scarcity and flood), and to investments in water supply and sanitation (WSS) as important factors in water security. We have demonstrated the scale of water-related risks using global-scale analysis, providing a basis for comparison between risks, and between countries. It has not been possible to monetize all of the impacts of water security;
a multi-attribute approach has allowed us to incorporate dimensions (most notably, of risks to the natural environment) that are more problematic to monetize. The analysis has demonstrated the following:
• Inadequate WSS has been estimated to be the largest water-related risk globally, in terms of economic and human impact. This is a chronic risk, materializing on a daily basis in countries without adequate water supply and sanitation infrastructure and services.
Improvements in access to sanitation have kept pace with global population growth, but the risk persists - and is increasing in Africa.
• Floods are a major and growing economic risk in all societies, and we project a growing proportion of flood risk in coastal megacities.
Asia stands out in this regard, because of large human exposure to flood risk. While Europe and North America have invested heavily to reduce the human and economic impacts of floods, they still face the greatest economic risks, and their exposure to the most extreme events continues to grow.
By the 2030s, in the absence of adaptation, coastal flood risk worldwide is projected to increase by a factor of four, while fluvial flood risk could more than double.
• Our analysis has demonstrated the complex effects of water insecurity on agricultural production, food prices, and the health of malnourished children. Water insecurity leads to higher and more-variable food prices (in particular, for rice) than would be expected in a more water-secure world.
Investment in water security could boost production, and reduce food prices and food price volatility for the world’s poorest consumers.
• The impacts of water insecurity on the natural environment are multiple and interacting. Ecosystem services in the regulation of runoff, assimilation of waste, and provision of fisheries, all underpin water security. We have demonstrated the extent of major risks to the aquatic environment, which need to be managed on the pathway to water security.
The analysis of risks has focused upon known physical mechanisms by which water-related risks harm people and the environment.
These impacts aggregate, and have broader impacts on the economy and society. We have demonstrated how the market can compensate for local impacts to some extent - for example, through food-trade and price adjustments - but markets are also a mechanism for
propagating risks globally. Perceptions of risk can modify investment choices: from those of individual farmers, to major foreign direct investment decisions. Extreme events - be they droughts, floods, disease outbreaks, or pollution
incidents - have particularly broad-ranging economic and political consequences.
These impacts interact with other contextual factors within society, and so become increasingly difficult to isolate and quantify.
The risk analysis methodology adopted here ensures that analysis of risk is grounded in known observable mechanisms, but it inevitably overlooks these broader scale impacts.
The analysis has drawn extensively on global datasets that are now becoming available, thereby providing exciting opportunities for the quantification of water security impacts.
While addressing most of the dimensions of water security already considered by previous studies (and in several instances, the same datasets), our approach is novel in its consistent focus upon hazards and impacts within a risk-based framework. We have sought to avoid commonplace ‘fragmented’ approaches to water, by addressing diverse aspects of water-related risk within this common framework.
The geographical aspect of our approach has helped to identify the spatial co-location of risks. The risk-based approach has also led to a focus upon the effects of hydrological variability. We have looked specifically at the effects of variability on agricultural production and prices. We have developed a metric of water scarcity that accounts for runoff and demand variability, the mitigating effect of storage, and the seasonal variability in the
environment’s requirement for water.
Analysis and quantification of risk provides the starting point for action to tackle water insecurity. It helps to prioritize action, target it geographically, and indicate the scale of an appropriate response. However, investment decision-making requires analysis of costs, impacts, and residual risks, on a case-by-case basis. Not all water security investments will be cost-beneficial.
The sequencing of investment in infrastructure, institutions, and information is essential - as we shall see in the next chapter. Nonetheless, our analysis has demonstrated that the risks of water insecurity are both globally significant, and unevenly distributed - providing a strong case for targeted action.
References
Arnell, N.W. (1999) Climate change and global water resources. Global Environmental Change, 9, S31-S49.
Briscoe, J. and Malik, R.P.S. (2006) India’s Water Economy. Bracing for a Turbulent Future. Oxford University Press, New Delhi, India.
Brown, C., Meeks, R., Ghile, Y., and Hunu, K.
(2013) Is water security necessary? An empirical analysis of the effects of climate hazards on national-level economic growth. Phil. Trans. R.
Soc. A, 371, 20120416.
Dankers, R., Arnell, N.W., Clark, D.B., Falloon, P.D., Fekete, B.M., Gosling, S.N., Heinke, J., Kim, H., Masaki, Y., Satoh, Y., Stacke, T., Wada, Y., and Wisser, D. (2014) First look at changes in flood hazard in the Inter-Sectoral Impact Model Intercomparison Project ensemble.
Proceedings of the National Academy of Sciences, 111(9): 3257-3261.
ECMWF (2014) European Centre for Medium-Range Weather Forecasts ERA Interim, Daily fields: http://apps.ecmwf.int/datasets/data/
interim_full_daily/
EM-DAT (2014) The OFDA/CRED International Disaster Database, 2014. Available from:
http://www.emdat.be
Environment Agency (2014) Flood And Coastal Erosion Risk Management: Long-Term Investment Scenarios (LTIS) 2014. Environment Agency, Bristol, UK.
Haddeland I., Clark, D.B., Franssen, W., Ludwig, F., Voß, F., Arnell, N.W., Bertrand, N., Best, M., Folwell, S., Gerten, D., Gomes, S., Gosling, S.N., Hagemann, S., Hanasaki, N., Harding, R., Heinke, J., Kabat, P., Koirala, S., Oki, T., Polcher, J., Stacke, T., Viterbo, P., Weedon, G.P., and Yeh, P. (2011) Multimodel estimate of the global terrestrial water balance: setup and first results.
J. Hydrometeor. 12(5): 869–884.
Hallegatte, S., Green, C., Nicholls, R.J., and Corfee-Morlot, J. (2013) Future flood losses in major coastal cities. Nature Climate Change, 3: 802-806
Hall, J.W. and Borgomeo, E. (2013) Risk-based principles for defining and managing water security. Phil. Trans. R. Soc. A, 371: 20120407.
Hinkel, J. and Klein, R.J.T (2009). Integrating knowledge to assess coastal vulnerability to sea-level rise: the development of the DIVA tool.
Global Environmental Change, 19(3): 384-395.
Hinkel, J., Lincke, D., Vafeidis, A.T., Perrette, M., Nicholls, R.J., Tol, R.S.J., Marzeion, B., Fettweis, X., Ionescu, C., and Levermann, A.
(2014) Coastal flood damage and adaptation costs under 21st century sea-level rise.
Proceedings of the National Academy of Sciences, 111(9): 3292-3297.
Hutton, G. (2013) Global costs and benefits of reaching universal coverage of sanitation and drinking-water supply. Journal of Water and Health, 11(1): 1-12.
IPCC (2012) Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. A Special Report of Working Groups I and II of the Intergovernmental Panel on Climate Change [Field, C.B., Barros, V., Stocker, T.F., Qin, D., Dokken, D.J., Ebi, K.L., Mastrandrea, M.D., Mach, K.J., Plattner, G.-K., Allen, S.K., Tignor, M., and Midgley, P.M. (eds.)]. Cambridge University Press, Cambridge, UK,
and New York, NY, USA, 582 pp.
Jeuland, M.A., Fuente, D.E., Ozdemir, S., Allaire, M.C., and Whittington, D. (2013) The longterm dynamics of mortality benefits from improved water and sanitation in less developed countries. PLoS ONE, 8(10): e74804.
Kriegler, E., Edmonds, J., Hallegatte, S., Ebi, K., Kram, T., Riahi, K., Winkler, H., and van Vuuren, D. (2014) A new scenario framework for climate change research: the concept of shared climate policy assumptions. Climatic Change, 122: 401-414.
Kundzewicz, Z.W., Kanae, S., Seneviratne, S.I., Handmer, J., Nicholls, N., Peduzzi, P., Mechler, R., Bouwer, L.M., Arnell, N., Mach, K., Muir-Wood, R., Brakenridge, G.R., Kron, W., Benito, G., Honda, Y., Takahashi, K., and Sherstyukov, B. (2014) Flood risk and climate change: global and regional perspectives. Hydrological Sciences Journal, 59(1): 1-28.
Lehner, B., Liermann, C.R., Revenga, C., Vörösmarty, C., Fekete, B., Crouzet, P., Döll, P., Endejan, M., Frenken, K., Magome, J., Nilsson, C., Robertson, J.C., Rödel, R., Sindorf, N., and Wisser, D. (2011) High-resolution mapping of the world’s reservoirs and dams for sustainable river-flow management. Frontiers in Ecology and the Environment, 9: 494-502.
Luechinger, S. and Raschky, P.A. (2009) Valuing flood disasters using the life satisfaction approach. Journal of Public Economics, 93(3-4): 620-632.
Pastor, A.V., Ludwig, F., Biemans, H., Hoff, H., and Kabat, P. (2014) Accounting for environmental flow requirements in global water assessments. Hydrol. Earth Syst. Sci., 18: 5041-5059.
Rosegrant, M.W. and the IMPACT Development Team (2012) International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT): Model Description. International Food Policy Research Institute (IFPRI), Washington, D.C.
Syvitski, J.P.M., Kettner, A.J., Overeem, I., Hutton, E.W.H., Hannon, M.T., Brakenridge, G.R., Day, J., Vörösmarty, C., Saito, Y., Giosan, L., and Nicholls, R.J. (2009) Sinking deltas due to human activities. Nature Geosci, 2: 681-686.
van Vliet, M.T.H., Yearsley, J.R., Ludwig, F., Vogele, S., Lettenmaier, D.P., and Kabat, P.
(2012). Vulnerability of US and European electricity supply to climate change. Nature Climate Change, 2: 676-681.
Vörösmarty, C.J., McIntyre, P.B., Gessner, M.O., Dudgeon, D., Prusevich, A., Green, P., Glidden, S., Bunn, S.E., Sullivan, C.A. Liermann, C.R., and Davies, P.M. (2010) Global threats to human water security and river biodiversity.
Nature, 467: 555-561.
Ward, P.J., Jongman, B., Weiland, F.S., Bouwman, A., Beek, R.V., Bierkens, M.F.P., Ligtvoet, W., and Winsemius, H.C. (2013) Assessing flood risk at the global scale: model setup, results, and sensitivity. Environmental Research Letters, 8, 044019.
WHO (2012) Global Costs And Benefits Of Drinking-Water Supply And Sanitation Interventions To Reach The MDG Target And Universal Coverage. World Health Organization Press, Geneva, Switzerland.
WHO UNICEF (2012) Joint Monitoring Programme (JMP) for Water Supply and Sanitation Data. Available: http://www.wssinfo.
org/data-estimates/introduction/. Accessed 2015 January.
Wilson, M.A. and Carpenter, S.R. (1999) Economic valuation of freshwater ecosystem services in the United States: 1971-1997.
Ecological Applications, 9: 772-783.
Winsemius, H.C., Van Beek, L.P.H., Jongman, B., Ward, P.J., and Bouwman, A. (2013) A framework for global river flood risk assessments. Hydrol.
Earth Syst. Sci., 17: 1871-1892.
World Bank (2012) Thai Flood 2011, Overview, Rapid Assessment for Resilient Recovery and Reconstruction Planning. The World Bank, Bangkok, Thailand.