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
| 
