Purpose
This Policy Position Statement (PPS) reviews the likely impact
of climate change on water resources in the UK, and sets out the
position of the Chartered Institution of Water and Environmental
Management (CIWEM) on how water resources should be planned and
managed in this context.
CIWEM calls for:
- Professionals working in water resources and associated areas
to make sure that they are aware of current thinking on climate
change and its impact on their area of work.
- Whenever a strategic or long-term decision about water
resources management is being made, the possible impact of climate
change must be considered.
- When climate change is being considered in water resources
decisions, care must be taken to ensure that decisions do
not:
- consider climate change as a factor when it should have no real
influence;
- fail to consider non-climate factors that have a greater
influence than climate change;
- fail to consider climate change when it may be central to making
the most appropriate decisions.
- In considering climate change in water resources decisions, the
full range of possible future climate scenarios to be taken into
account. It is not acceptable to choose a scenario because it is
easier to manage or because it illustrates a point.
- In considering climate change in water resources decisions, the
impact on water quality to be considered - climate change may lead
to more algal blooms, more storm surges leading to higher sediments
entering rivers, and more low flow events. These problems should
not be further aggravated by the option chosen.
- A preference to be given to water resources options that are
"no regrets" or "low regrets". Such options that will continue to
be of value through the full range of possible future
climates.
- The impact of energy use to be considered in water resources
decisions - there are opportunities to reduce energy use and the
emission of greenhouse gases. Reducing the demand for water
is a good way to control energy use and options to reduce water use
should be favoured.
- The impact of climate change on the environment to be
considered in water resources decisions - the environment will come
under additional pressure as a result of climate change, and steps
should be taken to reduce this as far as possible.
- Further research into the ways that water resources and the
water environment will be affected by climate change.
- Further research into the socio-economic impact of climate
change on water availability.
- Policies and laws that reconcile the needs of the environment,
people and businesses, and that are responsive to changing climatic
conditions.
- Clear communication to all water users on the effect of climate
change on resources and the actions that they can take to conserve
water and protect supply.
Background
There can be little doubt that our climate is changing as a
result of man's influence (see CIWEM's over-arching PPS on the
subject, 'Global Climate Change'). The Intergovernmental Panel on
Climate Change (IPCC) tells us that world wide, long-term changes
will be significant and affect many different aspects of life.
There is increasing evidence that the UK climate is already
starting to change. Globally, the 1990s was the warmest decade of
the last millennium. The present decade looks set to be even warmer
than the 1990s.
The UK Climate Impacts Programme's 2002 scenarios suggest that
winter rainfall will increase across the UK. Summer rainfall
may decrease by 30 to 50 percent by the 2080s. The largest
changes in precipitation in both summer and winter are in eastern
and southern England, while changes are smallest in north west
Scotland.
Extremes of weather are expected to become more common as a
result of climate change, with more frequent storms and heatwaves.
The impact of climate change on the frequency and severity of long
droughts is less clear, but we must prepare to deal with weather
patterns that we have not seen in the last century.
Predicting future climates is difficult and it is important to
understand the uncertainties surrounding the scenarios.
Key Issues - Water resources and climate change
Many aspects of water resources management will be affected by
climate change.
Increased temperatures and more marked seasonality in river
flows will cause additional stress to the water environment. Some
species may thrive but other populations may be seriously damaged.
The way that we use water will have an important part to play in
protecting the environment in the future.
People's demand for water is affected by the weather. Hot, dry
summers could lead to an increased demand for garden watering and
personal washing. In a crowded island, unlimited supplies of water
for non-essential uses should not be expected, and people can play
an important part in adapting to future climates.
Agricultural demand for water may also increase. Irrigated crops
are an important part of the UK's agricultural economy and it will
be important to make sure that limited supplies of water are used
effectively.
It seems likely that climate change will reduce the water
available for public water supply. Reservoir yields may reduce and
some groundwater sources could become less reliable. Droughts may
be more frequent. Short but intense summer season droughts
may become much more frequent than they have been in the
past. Long, multiple year droughts may not be either more
common nor less common than in the past, but when they do occur,
they are likely to be more intense, and will place water resources
systems under severe strain.
Adapting water supply for future climates will require
imaginative solutions that minimise further emissions of greenhouse
gases. These should favour resilience and flexibility. This may
include developing some new reservoirs but it is by no means clear
that this is the most appropriate solution. A full range of options
must be considered. Demand management is an effective way of both
improving resilience to climate change and reducing greenhouse gas
emissions. This could include changes to the way that water is
allocated between different uses and incentives for people and
business to save water.
June 2007
Note: CIWEM Policy Position Statements (PPS) represent the
Institution's views on issues at a particular point in time. It is
accepted that situations change as research provides new evidence.
It should be understood, therefore, that CIWEM PPS's are under
constant review, and that previously-held views may alter and lead
to revised PPS's.
