Water climate change impacts report card 2012 2013 (uk)
Living With Environmental Change
The report card covers the
• Evapotranspiration – water that
evaporates or is transpired by
trees and other plants
• River flows, floods and droughts
• Groundwater recharge and levels
• River water temperature
• River water quality and ecology
• Groundwater temperature and quality
• Water use
Climate Change Impacts
Report Card 2012 -13
This report card is for anyone who works with or has an interest in water in the UK.
It looks at the effect of climate change on fresh water – including rainfall, floods
and droughts. The report card is intended to help people understand the scale of
possible change and to help inform decisions about the way that water is managed.
Water is an essential and familiar part of everyday life, at home, at work and at
leisure. Water is at the heart of some of the most serious natural hazards faced in the
UK – floods and droughts. Climate change may have many impacts on water: while
some may be beneficial or easily managed, others require careful planning to avoid
This report card concentrates on fresh water, from source to sea. It complements
two other report cards – the Marine Climate Change Impacts Partnership (MCCIP)
marine report card and the Living With Environmental Change (LWEC) Terrestrial
Biodiversity Climate Change Impacts report card. Together, these start to build up
a picture of historical and future changes as a result of climate change. In time, we
expect these report cards to be joined by others that complete the picture of how
climate change is affecting and may further affect the UK.
The climate is changing
Global temperature has increased over the last fifty years, with the greatest warming in northern latitudes. Global
sea level is rising by about 3 mm every year. Across northern Europe rainfall increased significantly over the
twentieth century, with a decrease in rainfall in the Mediterranean region.
The UK climate is changing too
Temperatures have increased by about 1°C since 1980. Annual average rainfall has not changed since records
began in the 18th century, but in the last thirty years more winter rainfall has fallen in heavy events.
Many people will experience climate change through its effect on water
In the UK, many people will experience climate change through its effect on water, and especially through floods
and droughts. Average summer river flows may decrease through the twenty-first century across the UK, leading to
reduced water availability and lower river water quality. Floods may increase in both size and duration, particularly
We need to plan for future impacts to avoid unacceptable consequences
Actions to adapt to climate change must consider both the scale of the possible change and the variability of the
UK climate. Flexible solutions that can deal with a wide range of weather will usually be the best way forward.
Many actions will take many years to design and implement. This means that we need to anticipate future changes
and start to take steps to adapt to them now.
This water report card is an initiative of the LWEC partnership. LWEC brings together
UK public sector organisations that fund, carry out and use environmental research and
observations. LWEC aims to make sure that decision-makers in government, business
and society have the information, knowledge and methods they need to adapt to and
where possible benefit from environmental change. The water report card was developed
with funding and practical input from Defra (the UK Government’s Department for
Environment, Food and Rural Affairs), the Environment Agency, LWEC and the Natural
Environment Research Council.
The report card is in three parts:
• This high-level summary of the main findings
• A technical summary paper that covers the science in more detail
• A series of detailed scientific working papers, written by leading experts in their fields,
underpinning the report card with the best available science from the peer-reviewed
This high-level summary and the technical summary paper have been reviewed by a
group of independent experts to assure their quality. The water report card was steered
by an expert panel drawn from academia, consultancy and the water industry.
The source papers for this card are available from the LWEC website.
How was the report card developed?
High Force, Upper Teesdale
What is happening
Annual average rainfall has changed
little over the last three centuries. In
recent decades more winter rain has
fallen in heavy events.
High winter river flows
have increased especially
in the north and west.
Lake and river water
temperature is increasing.
There are no apparent
trends in ground water
Ground water and river water
quality has improved because of
There are no apparent
trends in low river flows.
The demand for water
has changed little over
the last decade.
Little known about
changes in evaporation.
What could happen*
Confidence Key Little change to annual rainfall
overall, but an increase in
winter rainfall and a decrease
in summer rainfall.
Increase in winter river
flows with more floods.
Continued increase in
lake and river water
Reduction in average
Reduced water quality in summer
as higher water temperatures
lead to more algal blooms.
Lower river flows in
The demand for water
may increase with higher
Increase in evaporation.
*By the 2050s
The UK has a temperate, moist climate, with mild winters and warm, but
not hot, summers. Average rainfall is highest in the west and north, with the
mountains of Wales, the English Lake District and the Highlands of Scotland
wettest: some parts receive over 3 metres of rainfall each year on average.
The lowlands of eastern England have the least rainfall, with some areas
seeing an average of less than 500 mm of rainfall a year. Annual average
temperatures are highest in the south of England, at 10 to 12°C. The warmest
areas are along the south coast and around London, and the same areas
have the hottest summer weather, but Cornwall has the mildest winters.
The coldest areas are the highest hills and mountains of the Pennines and
Scotland, where the annual average is below 4°C.
Climate and hydrology of the UK
The geology, soils and vegetation of the UK are varied, and these lead to
different hydrological responses to rainfall. The high land in the west and
north is mainly impermeable, which means that rainfall tends to run quickly
into streams and rivers. Rivers here are “flashy” – flows rise quickly after
rainfall, but fall quickly too once the rain has stopped. In southern and
eastern England the chalk rock is permeable; water sinks into the ground
(where it is called “groundwater”) and emerges slowly into rivers, sometimes
many months after the rain fell. This means that rivers in these areas tend
to respond slowly to rainfall, maintaining flows through all but the driest
summers. Limestone in the Cotswolds and the Pennines responds more
quickly than chalk but still acts as a reserve that maintains flows for some time
after the rain has finished.
The Lake District
The principal aquifers of the British Isles
Uses of water The main uses of water in England and Wales 2011
Across the UK, around 17 billion litres of clean drinking water
are supplied by water companies every day. Some water
users take water directly from rivers or groundwater – this
includes some homes without mains water supply, but
water taken directly is used mainly in farming, by industry,
and for electricity generation. In England and Wales, slightly
more fresh water is used for cooling power plants than for
mains water supply, even though many of the biggest power
plants are on the coast and use water from the sea or from
estuaries. Much of the water used by businesses and at
home is returned to rivers, after treatment to make sure
that river water quality is maintained. Water in lakes, rivers
and streams is essential for natural life too. Many people
use rivers, lakes and canals for recreation, including fishing,
boating or enjoying quiet time by the water. In the past, rivers
and canals were very important for the movement of goods;
now most boats on inland water are used for pleasure, and in
some places water-based tourism is an important part of the
*Private water supply 0.1%
Public water supply
Agriculture excluding spray irrigation
Diagram data source: Environment Agency
Globally, the climate has warmed at an increasing rate over
the last 50 years, with the greatest warming in northern
latitudes. Over the last 50 years the Arctic has warmed at
twice the rate of warming over land. In autumn 2012 the
Arctic sea ice area reached its lowest recorded extent at least
since satellite measurements began in the 1970s. For the
last two decades, global sea level has been rising at around
3 mm every year, the result of thermal expansion of water
and ice-melt. Sea-level change around the coast of the UK
is broadly following the global trend, taking into account
land movement. The oceans are becoming more acidic
because of the increased carbon dioxide in the atmosphere.
Taking northern Europe as a whole, annual rainfall increased
significantly over the last century, with a decrease in rainfall in
the Mediterranean region.
Patterns and trends in climate over smaller areas, such as the
countries of the UK, are harder to detect and to distinguish
from natural climate variability, yet it is at these and smaller
scales that the impact of climate change will be experienced
and where steps can be taken to manage the most significant
impacts. Locally, changes may not reflect global patterns.
This report card concentrates on the UK, but the past and
future changes reported here should be placed in this wider
context of a warming world. People in the UK will be affected
not only by direct changes in local climate but also by
changes in other parts of the world, for example as cropping
patterns change in the countries that grow some of our food.
1971-2000 (deg C)
0 - 2
2 - 4
4 - 6
6 - 8
8 - 10
10 - 12
450 - 700
700 - 1000
1000 - 1300
1300 - 1700
1700 - 2200
2200 - 2800
2800 - 4650
Guernsey: 824 mm
Jersey: 843 mm
Annual average rainfall between 1971 and 2000 Annual average temperature between 1971 and 2000
2012 – an unusual year
The year 2012 was an unusual year in the UK. The whole calendar year was
the second wettest in the UK-wide series that starts in 1910, and just a few
millimetres short of the record for the wettest year set in 2000. Both April and
June had record high rainfall, and summer 2012 was the second wettest in
the UK-wide series, though not as wet as 1768 or 1872 in the much longer
England and Wales series. This exceptional rainfall came after two very dry
years in England, and the first three months of 2012 were also very dry.
The impact of climate change on recent weather is the subject of ongoing
research. Recent cool summers in the UK do not reflect the global picture of
warming: globally, 2012 was one of the ten warmest years on record, and nine
of the ten warmest years occurred since 2000.
Commuters in heavy rain in Manchester April 2013
In developing the report card we wanted to be clear about our confidence
in the statements of change. For this reason we have attached a confidence
level – high, medium, low – to each of the subject areas. This confidence
level, assigned by scientific experts, reflects both the degree of agreement
of scientific studies and the amount of information available. For example,
we would have low confidence in a conclusion drawn from a few studies
that disagreed, but high confidence where a large number of separate
investigations led to the same conclusion. The confidence level here is
specifically about the link to climate change. For example, we are confident
that UK temperatures have increased as a response to climate change, so
this is assigned high confidence. In contrast, we are very confident that water
quality has improved over the last 30 years, but there is very little information
about the impact of climate change on water quality, so this is given a low
Amount of evidence (type,
amount, quality, consistency)
The Report Card has simplified the assessments to provide an overall confidence level of high (H), medium
(M) or low (L). Low confidence results are still based on evidence and still reflect expert judgment.
The Report Card
Over the next few pages we give the main findings of the report card. The first column gives the subject and provides a link for more
information. This link is either a published report (for example, the latest UK climate projections) or one of the working papers developed
especially for the water report card. The next two columns explain what has happened so far and what may happen over the rest of the
What could happen
Jenkins et al. 2008
Jenkins et al. 2008,
Murphy et al. 2009,
Watts et al. 2013
What has happened
Central England temperature has increased by approximately 1°C
Rainfall varies from year to year but there is no trend in annual
average England and Wales rainfall in the long series that began in
Winter rainfall in England and Wales has increased since the
1760s, but with little change over the last 50 years.
Winter rainfall in Scotland and parts of northern England has
increased in the last 50 years.
Over the last thirty years, more winter rain has been falling in heavy
Summer rainfall varies greatly but appears to have decreased in
England and Wales since the 1760s, though the trend is hard to
Temperatures will increase across the UK, with the greatest
changes in summer.
The latest UK climate projections, UKCP09, suggest that annual
average rainfall may not change much over the twenty-first century.
In winter, the biggest changes in precipitation may be along the
western side of the UK, with increases of up to a third by the end
of the century. Decreases of a few percent may occur over parts of
the Scottish Highlands. Uncertainties in seasonal rainfall projections
In summer, the biggest changes in precipitation, with a reduction
of about 40% by the end of the century, may be in parts of the far
south of England. Changes close to zero may occur over parts of
northern Scotland. Uncertainties in seasonal rainfall projections are
There is more confidence that high seasonal rainfall extremes
will increase as a result of climate change, with a corresponding
increase in the biggest floods.
There are few studies of historical evapotranspiration and there is
little reliable information on how this has changed over time.
Annual runoff has increased since the 1960s in Scotland, Wales
and parts of northern and western England; in contrast, no
pronounced changes have occurred in the lowlands of southeast
Winter flows have increased in upland, western catchments.
Autumn flows have increased in central England and parts of
eastern Scotland. There is no apparent pattern of change in
summer flows across the UK.
High winter flows have increased over the last 30 years and there
has been an increase in the frequency and magnitude of flooding
over the same period, particularly in the west and north. These
changes cannot be attributed to climate change.
There is little evidence of changes in very low flows and no clear
pattern of droughts.
Potential evapotranspiration is expected to increase in the UK over
the rest of the century in response to increased air temperatures,
but there may be decreases in some months. The range of
possible changes is large, mainly due to uncertainty in projections
of wind speed and moisture availability for plant growth, which also
have an effect on evapotranspiration.
Projections of future river flow are uncertain because of
uncertainties in both future rainfall and evapotranspiration. Studies
tend to agree on a trend towards similar or slightly increased
average winter flows and reduced average summer flows, with
mixed patterns in spring and autumn.
There is more confidence about increased high flows and flooding
over the century because of increased rainfall, particularly in winter,
but there is a wide range of projections.
Some studies indicate increases in the magnitude and frequency
of short droughts (18 months), but there is little information on
changes in longer droughts.
What could happenWhat has happened
River flows, floods
Kay et al. 2013
While there are extensive records of groundwater levels across
the UK, little is known about how groundwater has responded to
climate change. This is partly because the climate change signal
is likely to be small compared to other influences on groundwater
such as land-use change and abstraction, but also because
groundwater systems are naturally highly variable and their
response to changes in rainfall and evapotranspiration is likely to
UK river temperature has increased over the latter half of the
twentieth century, broadly in line with changes in air temperature.
Changes have not been attributed to climate change as the
processes (energy exchanges and flow) that control water
temperature are complex.
Most, but not all, studies agree that there may be a decrease in
recharge to groundwater throughout the century. By the 2050s
changes in groundwater recharge are projected to be somewhere
in the range from a 30% reduction up to a 20% increase. There is
most agreement for chalk catchments in southern England, where
increased temperatures may contribute to a reduction in the length
of the recharge season (groundwater recharge occurs mainly
between late autumn and early spring).
River water temperature is expected to increase across the UK
through the twenty-first century, mainly as a response to increased
energy inputs. The rate and pattern of change is not clear.
Increases in water temperature will be modified by hydrological
changes, which may either magnify or reduce the impact of
changes in energy input.
Bloomfield et al.
2013, Jackson et al.
Hannah and Garner
What could happenWhat has happened
Bloomfield et al.
River water quality
Whitehead et al.
2013, Ormerod and
Over the last 30 years there has been an overall improvement
in river water quality, although nutrient levels have increased as
a result of the use of fertilisers. Improvements have mainly been
achieved through regulation of both point source discharges and
a reduction in toxic pollution. Upland catchments have begun
to recover from acidification as a result of reductions in sulphur
emissions since the 1980s. These changes have not been linked to
There is some evidence that freshwater ecosystems may be
responding to changes in water temperature, for example with
reductions in some fish species in some catchments.
There is little information on groundwater temperature.
Overall, groundwater quality has improved due to tighter regulation
of various sources of pollution. An exception is an increase in
nitrate levels in groundwater during the last half of the twentieth
century, which is consistent with increases in agricultural fertiliser
application. These changes have not been linked to climate change.
Changes in river flow patterns may lead to changes in the
mobility and dilution of nutrients and contaminants. Higher water
temperatures will increase chemical reactions and biological
Lower summer flows may enhance the potential for algal and
cyanobacterial blooms and reduce dissolved oxygen levels. Storms
may flush nutrients and other pollutants from urban and rural areas
and may cause acid pulses in some upland catchments.
Increased water temperatures may threaten cold-water fish
species, with invasive and non-native fish species finding
conditions more favourable. Future conditions are expected to be
more favourable to invasive species.
Other changes may be complex and there is little information on
how freshwater ecosystems will respond to the combined effects
of river flows and water temperature and other changes to water
There has been little research on how groundwater temperature
Groundwater quality is expected to respond to changes in
recharge and the presence of pollutants and nutrients, but the
scale and pattern of changes is unclear.
What could happenWhat has happened
What could happenWhat has happened
Knox et al. 2013,
Rance and Wade
Public water supply demand is partly linked to temperature,
with greater water demand on hot days. There is no evidence
that increasing average temperatures in the UK have yet led to
increased demand. This may be because the trend cannot be
distinguished from other factors that influence demand.
Agricultural demand for water for irrigation has increased over the
last two decades, but this increase cannot be linked to climate
Demand for public water supply may increase with temperature.
The main changes are expected to be for increased outdoor use,
such as garden watering, and perhaps an increased frequency of
showering and bathing.
Water demand for agriculture is expected to increase with
temperature, as crops may need more irrigation to counteract
warmer, drier periods. However, increases may be constrained by
the availability of suitable soils for growing irrigated crops.
What are the implications of climate change? Adapting to climate change
The UK Government’s 2012 Climate Change Risk Assessment (CCRA) assessed the main
risks and opportunities in the UK from climate change, setting these in context and allowing
comparison between different sectors. In all five themes of the CCRA – agriculture and forestry,
business, health and wellbeing, buildings and infrastructure, and natural environment – water
features high up the list of possible risks.
The risks to agriculture and forestry include the problem of drier soils, reducing crop and
timber yields and leading to extra demand for water for irrigation. At the same time, increased
flooding could reduce the productivity of high-quality agricultural land, which is often in the
floodplain. Warmer and drier summers could lead to more wildfires.
For businesses the main climate risks include flooding, increased competition for water, and
the disruption of transport networks and communication links, for example by floods. There
are also indirect risks from changes in agriculture and the natural environment.
People’s health and wellbeing is particularly affected by flooding, not only through direct
injuries and deaths but also because there can be mental health effects. Water-borne diseases
may also become more of a problem with increasing temperatures.
Buildings and infrastructure may be affected both by extreme weather and long-term
changes in climate. Energy infrastructure is at significant risk from flooding. Increased energy
demand may increase the demand for water to cool power stations. Roads and railways are
disrupted by flooding, and river bridges are at risk from erosion when river flows are high. Our
water supply depends on rainfall, and increased rainfall variability may make provision of water
supply more difficult. Buildings can be damaged by flooding.
The natural environment depends on water in many ways. Lower summer river flows may
lead to poor water quality. Warmer rivers and lakes may suit some species, but others will not
thrive. Flooding and erosion can damage important habitats.
The possible risks identified here show the importance of
adapting to climate change. For many of these water risks
there is still considerable uncertainty about the nature and
extent of possible changes. Further research and analysis
should reduce this uncertainty, but it is very unlikely to be
eliminated. This means that many adaptation plans will need
to be able to cope with a wide range of possible changes,
pointing towards the need for plans that are flexible and
The UK Government’s first National Adaptation Programme
(NAP) was published in the summer of 2013. It sets out the
roles of government, the private sector and others in meeting
the challenge of climate change, including the Government’s
adaptation policies and actions.
Technical papers and contributors
Further reading and resources
Climate Ready is Defra’s support service for businesses and
sectors that want to know more about adapting to climate
change. On the Climate Ready website you can find out more
about assessing vulnerability to climate change and the steps
you can take to adapt. The web resources are available free of
charge to anyone in the UK.
UKCP09 – the 2009 UK climate projections – are the latest,
most detailed projections for the UK.
More details on the science of climate change can be found
on the UK Met Office website.
For an international view on climate change, the
Intergovernmental Panel on Climate Change has a series of
reports and papers available.
The Government has published its National Adaptation Plan
This is a list of the papers referred to in the document. Most of these are working papers, developed specifically to support the LWEC report
card. These in turn provide a wide bibliography of published UK research into the past and future impacts of climate change.
The technical summary paper – pulling the main points
of this work together, is:
Watts G, Battarbee R, Bloomfield J, Crossman J, Daccache
A, Durance I, Elliot J, Garner G, Hannaford J, Hannah DM,
Hess T, Jackson CR, Kay AL, Kernan M, Knox J, Mackay
JD, Monteith DT, Ormerod SJ, Rance J, Stuart ME, Wade A,
Wade SD, Weatherhead EK, Whitehead PG and Wilby RL
(2013) Climate change and water in the UK – past changes
and future prospects.
1. Bloomfield JP, Jackson CR and Stuart ME (2013).
Changes in groundwater levels, temperature and quality
in the UK over the 20th century: An assessment. LWEC
2. Hannaford J (2013). Observed long-term changes in UK
river flow patterns: a review. LWEC working paper.
3 Hannah DM and Garner G (2013). Water temperature.
LWEC working paper.
4 Jackson, CR, Mackay JD and Bloomfield JP (2013).
Changes in groundwater levels in the UK over the 21st
century: an assessment of evidence of impacts. LWEC
5 Kay AL, Bell VA, Blyth EM, Crooks SM, Davies HN and
Reynard NS (2013) A hydrological perspective on UK
evaporation: historical trends and future projections.
LWEC working paper.
6 Knox J, Weatherhead EK, Hess T and Daccache A
(2013). Climate change impacts on future water demand
for irrigated agriculture in England and Wales. LWEC
Papers and references
7 Ormerod SJ and Durance I (2013). Climate change and
the UK’s freshwater ecosystems. LWEC working paper.
8 Rance J and Wade SD (2013). The possible impacts of
climate change on public water supply availability over
the 21st century. LWEC working paper.
9 Whitehead PG, Battarbee RW, Crossman J, Elliot JA,
Wilby RL, Monteith DT and Kernan M (2013). River and
lake water quality – future trends. LWEC working paper.
10 Wilby RL (2013). Future flood – magnitude and frequency.
LWEC working paper.
Jenkins GJ, Perry MC, and Prior MJ (2008). The climate of the
United Kingdom and recent trends. Met Office Hadley Centre,
Murphy JM, Sexton DMH, Jenkins GJ, Boorman, PM, Booth
BBB, Brown CC, Clark RT, Collins M, Harris GR, Kendon EJ,
Betts RA, Brown SJ, Howard TP, Humphrey KA, McCarthy
MP, McDonald RE, Stephens A, Wallace C, Warren R, Wilby
R, Wood RA (2009), UK Climate Projections Science Report:
Climate change projections. Met Office Hadley Centre, Exeter.