Assessment versions

Published (reviewed and quality assured)

• No published assessments

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

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

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.

Data specifications

EEA data references

• No datasets have been specified here.

External data references

• DONAR (Historical water measurement data)
• River Danube water temperature measurements
• Water temperature in Lake Võrtsjärv
• Hydrology and Water Resources Management Data system

Data sources in latest figures

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