Climate Change 2001: Working Group II: Impacts, Adaptation and Vulnerability

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4.6.5. Adaptation to Climate Change in the Water Sector: an Overview

Water managers are accustomed to adapting to changing circumstances, many of which can be regarded as analogs of future climate change, and a wide range of adaptive options has been developed. Supply-side options are more familiar to most water managers, but demand-side options increasingly are being implemented. Water management is evolving continually, and this evolution will affect the impact of climate change in practice. For reasons noted above, climate change is likely to challenge existing water management practices, especially in countries with less experience in incorporating uncertainty into water planning. The generic issue is incorporation of climate change into the types of uncertainty traditionally treated in water planning.

Integrated water resources management (IWRM) (Bogardi and Nachtnebel, 1994; Kindler, 2000) increasingly is regarded as the most effective way to manage water resources in a changing environment with competing demands. IWRM essentially involves three major components: explicit consideration of all potential supply-side and demand-side actions, inclusion of all stakeholders in the decision process, and continual monitoring and review of the water resources situation. IWRM is an effective approach in the absence of climate change, and there already are many good reasons for it to be implemented. Adopting integrated water resources management will go a long way toward increasing the ability of water managers to adapt to climate change.

There are three final points to make:

1. “Upstream” adaptation may have implications for “downstream” uses. In other words, the impact of climate change on one user may be very much determined by the actions of other users in response to climate change. This emphasizes the need for basin-scale management.
   
2. The emphasis in this section has been on managed water systems. In many countries, particularly in rural parts of the developing world, water supply is “managed” at the household level, utilizing local water sources. There is a need to look at the implications of climate change in circumstances of this type in which investment in substantial infrastructure is unlikely.
3. Adaptation to climate change to reduce vulnerability in the water sector should involve far more than just water managers. Increasing social vulnerability to water stress (in terms of drought and flood) in many parts of the world reflects a wide range of pressures, many of which are outside the responsibility of water managers. Reducing vulnerability to climate change-induced flood and drought will require decisions about issues such as development and planning control, fiscal incentives (such as subsidized insurance or government disaster relief) to occupy (and continue to occupy after loss) hazard-prone land, and wealth enhancement