Water temperature

Indicator Assessment
Prod-ID: IND-202-en
Also known as: CLIM 019
expired Created 08 Sep 2008 Published 08 Sep 2008 Last modified 25 Aug 2017
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During the last century the water temperature of some European rivers and lakes increased by 1-3 o C, mainly as a result of air temperature increase, but also locally due to increased inputs of heated cooling water from power plants. In line with the projected increases in air temperature, lake surface water temperatures may be around 2 o C higher by 2070.

Update planned for November 2012

Key messages

  • During the last century the water temperature of some European rivers and lakes increased by 1-3 oC, mainly as a result of air temperature increase, but also locally due to increased inputs of heated cooling water from power plants.
  • In line with the projected increases in air temperature, lake surface water temperatures may be around 2 oC higher by 2070.

Water temperatures in four selected European rivers and lakes in the 20th century

Water temperatures in four selected European rivers and lakes in the 20th century

Note: Annual average water temperature in River Rhine (1909-2006), River Danube (1901-1998), Lake Võrtsjärv (1947-2006), and average water temperature in August in Lake Saimaa, Finland (1924-2000).

Data source:

Source 1) Trend in River Rhine water temperature 1910-2006. Rijkswaterstaat, measurements Rhine River at Lobith period 1908-2006 (non published), 2007. Timo Kroon, RIZA; t.kroon@riza.rws.minvenw.nl Source 2) Trend in River Danube water temperature 1901-1990, 2006. Severin Hohensinner; severin.hohensinner@boku.ac.at Source 3) Trend in August water temperature in Lake Saimaa 1924-2000, 2006. Korhonen Johanna; johanna.korhonen@ymparisto.fi Source 4) Trend in water temperature in Lake Võrtsjärv (1947-2006), 2007. Peeter Noges & Tiina Nõges; peeter.noges@jrc.it tiina.noges@emu.ee

Downloads and more info

Past trends

Long time-series, covering the past 100 years, show that the surface water temperatures of some of the major rivers in Europe have increased by 1-3 oC over the last century (Figure 1). The temperature of the river Rhine increased by 3 oC between 1910 and 2006. Two-thirds of this is estimated to be due to the increased use of cooling water in Germany and one-third to the increase in temperature as a result of climate change (MNP, 2006). In the river Danube the annual average temperature increased by around by 1 oC during the last century. A similar temperature increase was found in some large lakes: Lake Vortsjarv in Estonia had a 0.7 oC increase between 1947 and 2006 and the summer (August) water temperature of Lake Saimaa, Finland increased more than 1 oC over the last century. There are many shorter time-series of water temperature covering the past 30-50 years and the general trend has been for   temperatures in European freshwater systems to increase, generally by from 0.05 to 0.8 oC/decade.
George and Hurley (2004) found that the temperature of Lake Windermere (England) and Lough Feeagh (Ireland) increased by 0.7-1.4 oC between 1960 and 2000. The water temperature of Lake Veluwe (the Netherlands) has increased by more than 1 oC since 1960 (MNP, 2006).
Marked increases in water temperature were found in eight Lithuanian lakes (Pernaraviciute, 2004) and six Polish lakes (Dabrowski et al., 2004). Since 1950, water temperatures in rivers and lake surface waters in Switzerland have in some cases increased by more than 2 oC (BUWAL, 2004; Hari et al., 2006). In the large lakes in the Alps the water temperature has generally increased by 0.1-0.3 oC per decade: Lake Maggiore and other large Italian lakes (Ambrosetti and Barbanti, 1999), Lake Zurich (Livingstone, 2003), Lake Constance and Lake Geneva (Anneville et al., 2005).
Dokulil et al. (2006) studied the trend in hypolimnion (bottom water) temperature in 12 deep European lakes and found generally a temperature increase of 0.1-0.2 oC per decade. This may have significant effects on thermal stratification and mixing of water in lakes, which in turn affects deep water oxygen conditions and nutrient cycling.

Projections

As water temperature is closely linked to change in air temperature, the predicted increase in air temperature due to climate change will be reflected in increased surface water temperature. This is in addition to temperature changes caused by other factors, such as changes in cooling water releases. Projected increases in surface water temperatures are often 50 to 70 % of the projected increases in air temperature. In line with the projected increases in air temperature, lake surface water temperatures may be around 2 oC higher by 2070, but with a clear seasonal dependency and depending on lake properties (Malmaeus et al., 2006; George et al.,  2007).

Indicator specification and metadata

Indicator definition

  • Water temperatures in four selected European rivers and lakes in the 20th century

Units

http://www.eea.europa.eu/publications/eea_report_2008_4/pp76-110CC2008_ch5-4to6_Water_quantity_and_quality.pdf


Rationale

Justification for indicator selection

Since water temperature is mainly determined by heat exchange with the atmosphere, higher air temperatures lead to higher water temperatures. Higher water temperatures, particularly in standing waters and low-flow situations in rivers, will bring about changes in the physico-chemical condition of water bodies with subsequent impacts on biological conditions. This may have severe consequences for ecosystem structure and function as well as for water use and ecosystem services.
Impacts of increased water temperatures may also include more stable vertical stratification of deep lakes and increased oxygen depletion in lake bottoms (stratification in other lakes may become less stable), more frequent harmful algal blooms, reduced habitats for cold-water aquatic species, and increased incidence of temperature-dependent diseases.
Human intervention can only help freshwater ecosystems to adapt to increasing water temperature in a limited way, for example by reducing the pressures from other human activities such as pollution by nutrients and hazardous substances and pressure from hydromorphological modifications. Such actions may make the water bodies less vulnerable to stress resulting from higher water temperature. Additional pollution load reduction measures may be needed in river basin management plans to obtain good ecological status, as required by the Water Framework Directive.

Scientific references

  • No rationale references available

Policy context and targets

Context description

In April 2009 the European Commission presented a White Paper on the framework for adaptation policies and measures to reduce the European Union's vulnerability to the impacts of climate change. The aim is to increase the resilience to climate change of health, property and the productive functions of land, inter alia by improving the management of water resources and ecosystems. More knowledge is needed on climate impact and vulnerability but a considerable amount of information and research already exists which can be shared better through a proposed Clearing House Mechanism. The White Paper stresses the need to mainstream adaptation into existing and new EU policies. A number of Member States have already taken action and several have prepared national adaptation plans. The EU is also developing actions to enhance and finance adaptation in developing countries as part of a new post-2012 global climate agreement expected in Copenhagen (Dec. 2009). For more information see: http://ec.europa.eu/environment/climat/adaptation/index_en.htm

Targets

No targets have been specified

Related policy documents

No related policy documents have been specified

Methodology

Methodology for indicator calculation

http://www.eea.europa.eu/publications/eea_report_2008_4/pp76-110CC2008_ch5-4to6_Water_quantity_and_quality.pdf

Methodology for gap filling

http://www.eea.europa.eu/publications/eea_report_2008_4/pp193-207CC2008_ch8_Data_gaps.pdf

Methodology references

No methodology references available.

Uncertainties

Methodology uncertainty

http://www.eea.europa.eu/publications/eea_report_2008_4/pp193-207CC2008_ch8_Data_gaps.pdf

Data sets uncertainty

http://www.eea.europa.eu/publications/eea_report_2008_4/pp193-207CC2008_ch8_Data_gaps.pdf

Rationale uncertainty

No uncertainty has been specified

Data sources

Metadata

Topics:

information.png Tags:
, , ,
DPSIR: Impact
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • CLIM 019
Temporal coverage:
information.png Geographic coverage:

Countries

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Dates

First draft created:
08 Sep 2008, 12:00 AM
Publish date:
08 Sep 2008, 12:00 AM
Last modified:
25 Aug 2017, 11:50 AM

EEA Contact Info

Peter Kristensen

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For references, please go to https://www.eea.europa.eu/data-and-maps/indicators/water-temperature/water-temperature-assessment-published-sep-2008 or scan the QR code.

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