Select Committee on Environment, Food and Rural Affairs Written Evidence


Memorandum submitted by Dr Thomas E Downing

CLIMATE CHANGE AND WATER SECURITY

  1.  Last year an interdisciplinary team produced a national assessment of climate change and demand for water in the UK. A summary of that assessment will be presented to the CIWEM meeting in mid May (and has been sent to the Clerk of the Committee). The full report and executive summary are available on http://www.sei.se/oxford/ccdew/index.html. The table below presents the overall results.

  2.  In this short submission, I would like to reflect on the findings of the CCDeW project and place the risk of climate change in the broader context of water management. The first observation is that climate change is both a threat and an opportunity. The threats have been well-documented and widely reported: more intense and more frequent flooding, drying out of some regions, higher demand for water and potentially intense and persistent drought.

  3.  Less clear perhaps is that climate change opens up new opportunities as well. The first generation of climate change impacts studies focussed on "what if" scenarios, mostly of adverse impacts. At present, attention is increasingly focussing on the character of socio-economic and environmental vulnerability and pathways for effective adaptation. Water systems are highly adaptive. Social analysts often contrast public attitudes before and after privatisation: public acceptance of risk replaced by water as an affordable commodity separated from its environmental, economic and social context. Perhaps public recognition of climate change may be an opportunity to locate water security in a public debate with the expectation that consumers will take on some element of risks in managing their futures.

  4.  The second observation is that demand for water is essentially behavioural. In contrast to water supply, how we choose to use water is about individual choice on time steps ranging from sub-daily consumption (eg, how deep to fill the bath) to the long term implication of technological change (eg, installing a power shower) and even garden design. The example of Zurich is instructive. In 1977 Zurich ran out of water—unthinkable in a high rainfall country like Switzerland. The response was a set of emergency measures to encourage households to conserve water and to adopt water saving technologies. At the same time, the public water supply was greatly expanded. At present, the capacity of the water system far exceeds actual demand. The public utility is not able to recover all of its costs-consumers are reluctant to vote for higher prices when they are using less water. Water quality problems with the low flow of water in pipelines have occurred as well. The interactions of a social consciousness, new technologies and a concerted shift in policy shift have altered the supply-demand balance.

  5.  I conclude with a third observation: an integrating framework for risk management is required. At present the supply-demand balance is evaluated through a static analysis of "headroom" over a planning horizon of a decade or more. Levels of service are taken as given, without challenging the robustness and context of market surveys. The fine scale of peaks in daily and seasonal demand is largely divorced from the long-term expansion of supply. The role of stakeholders in actively managing their risks, in switching between uses during times of crises, and in local planning for future water use is rarely an effective component of an assessment.

  6.  Adapting to climate change is more than adding up the numbers. We should avail ourselves of the opportunity to take a fresh approach to risk management.

IMPACTS OF CLIMATE CHANGE ON WATER DEMAND FOR SELECTED COMPONENTS

DOMESTIC DEMAND


2020s
2020s
2050s
Low
Medium-High
Medium-High

Alpha
1.4-1.8%
Beta
2.7-3.7%
Gamma
0.9-1.2%
Delta
1.0-1.3%


INDUSTRIAL/COMMERCIAL DEMAND


2020s
2020s
2050s
Low
Medium-High
Medium-High

Alpha
1.7-2.7%
Beta
1.8-3.0%
3.6-6.1%
Gamma
1.8-2.9%
2.0-3.1%
Delta
1.7-2.7%


AGRICULTURAL DEMAND


2020s
2020s
2050s
Low
Medium-High
Medium-High

Alpha
19%
Beta
19%
26%
Gamma
18%
19%
Delta
20%


  Source: CCDeW final report and executive summary.

TOTAL IMPACTS OF CLIMATE CHANGE ON DEMAND FOR WATER IN ENGLAND AND WALES


Climate change
EA Reference
Low
Med High
Med High(2050s)

Alpha
1.4%
Beta
2.0%
3.8%
Gamma
1.8%
2.0%
Delta
1.8%


  Source: CCDeW final report and executive summary.

  The shading in the 2050s cell indicates a rough estimate of the total regional effect of climate change on water demand.

  The EA reference scenarios (alpha, beta, gamma and delta) are limited for 2024-25, based on the DTI Foresight scenarios. The climate change scenarios are from the UKCIP2002 data base.

Dr Thomas E Downing

Stockholm Environment Institute, Oxford

April 2004



 
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