Adapting to climate change in the water sector

This background note, published by the Overseas Development Institute, provides an overview of the potential risks and vulnerabilities that face the water sector due to climate change. It also summarises of some of the adaptive strategies, targeting both supply and demand of water, being employed across various sectors in the developing world and offers suggestions going forward. It concludes by assessing how current knowledge of climate change can help inform future planning of water sector interventions. Acknowledging the inherent difficulties of predicting complex systems, the document divides the impacts of climate change on the water sector into knowns and unknowns. On the supply side, it is generally accepted that precipitation will increase at higher latitudes and in the tropics, but decrease in the sub-tropics. Growing evidence shows decreased snow cover in many regions as well as valuable glacial resources (with a projected loss of 60 per cent by 2050). The result is changes in flood and drought patterns putting many more people at risk. Urbanisation, rising populations, rising sea level, bio-fuel production and agriculture are all expected to greatly increase demand for water. These are all trends however; other factors are much more difficult to predict, namely socio-political events, markets and local-scale climate modelling. Four broad options are outlined for adaptive approaches.

• Hazards-based approach – reduces risks and uses climate scenarios to assess future vulnerabilities.
• Vulnerability-based approach – aims to ensure a minimum threshold of vulnerability is not exceeded.
  
• Adaptive-capacity approach – assesses and improves adaptive capacity to better cope with variability.
  
• Policy-based approach – aims for robust climate change policies, through mainstreaming and climate proofing.
  

Several examples of different water sector interventions found in the National Adaptation Programmes of Actions by LDCs and it is noted that the vast majority are supply-side interventions, with only a few examples (including Eritrea and Lesotho) aiming to put in place supply and demand side legislation. Limitations are highlighted in recognition that issues of social and political access are rarely addressed. It is suggested that adaptation policies should be responsive to socio-economic and political contexts, and provide suitable options for different scales of farm. It is also suggested that integrated management, as encapsulated by Integrated Water Resources Management (IWRM), can with enough financing and institutionalisation (something that has proven difficult) help with decision-making. Focus should be on the development of better planning and more comprehensive resource and drought mapping.