Indicator Assessment

Lake and river ice cover

Indicator Assessment
Prod-ID: IND-190-en
  Also known as: CLIM 020
Published 20 Nov 2012 Last modified 11 May 2021
7 min read
This page was archived on 03 Feb 2017 with reason: No more updates will be done
  • The existence of ice cover and the timing of ice break-up influence the vertical mixing of lakes and are therefore of critical ecological importance.
  • The duration of ice cover on European lakes and rivers has shortened at a mean rate of 12 days per century over the last 150–200 years.
  • A further decrease in the duration of lake ice cover is projected with projected climate change.

This indicator will be discontinued in January 2017.

This indicator is discontinued. No more assessments will be produced.

Past trends

The duration of ice cover in the northern hemisphere has shortened at a mean rate of 12 days per century over the last 150–200 years, resulting from a 5.8 day later ice cover and a 6.5 day earlier ice break-up on average [i].

There are, however, large differences across regions. At the Hungarian section of the River Danube, the date of first ice appearance has shifted 19–29 days later over the 1876–2011 period, while the date of final ice disappearance shifted 18–23 days earlier [ii] (see Figure 1.a). In Lake Kallavesi, eastern Finland the freezing date has shifted 15 days later in 1833–2011, while the breakup date has shifted 12 days earlier in 1822–2011 [iii] (see Figure 1.b).


One recent study has simulated changes in lake ice cover throughout the Northern Hemisphere (40– 75 °N) based on one global climate model driven by the SRES A2 emission scenario. The results indicate an overall decrease in the duration of lake ice cover of 15–50 days across regions by 2040–2079, compared to the baseline period 1960–1999 [iv]. The ice cover of lakes in regions where the ice season is already short or where ice cover only occurs in cold winters is generally more strongly affected by increasing temperature than that of lakes in colder regions [v]. However, the ecological consequences of reduced ice cover are expected to be lower in areas where ice cover normally is less frequent and ecosystems thereby are adapted to less ice or ice-free conditions.

[i] John J. Magnuson et al., „Historical Trends in Lake and River Ice Cover in the Northern Hemisphere“, Science 289, Nr. 5485 (August 9, 2000): 1743–1746, doi:10.1126/science.289.5485.1743; EEA, Impacts of Europe’s changing climate - 2008 indicator-based assessment. Joint EEA-JRC-WHO report EEA Report (Copenhagen: European Environment Agency, September 29, 2008),

[ii] Katalin Takács, „Changes in river ice regime of the River Danube“ (Eötvös Loránd University, 2011),

[iii] SYKE, „Lake ice in Finland - observed trends and future outlooks.“, Finnish Environment Institute, 2011,

[iv] Y. Dibike et al., „Response of Northern Hemisphere lake-ice cover and lake-water thermal structure patterns to a changing climate“, Hydrological Processes 25 (2011): 2942–2953, doi:10.1002/hyp.8068.

[v] G. A. Weyhenmeyer et al., „Large geographical differences in the sensitivity of ice-covered lakes and rivers in the Northern Hemisphere to temperature changes“, Global Change Biology 17 (2011): 268–275, doi:10.1111/j.1365-2486.2010.02249.x.

Supporting information

Indicator definition

  • Observed change in duration of lake and river ice cover a) Danube River, at Budapest, 1876–2011 and b) Lake Kallavesi, Finland, 1833–2011.


  • Ice break-up dates of lakes and rivers (day of the year)


Policy context and targets

Context description

Ice cover of rivers and lakes is one of the parameters that determine function of aquatic ecosystems. Preparing for climate change is a major challenge for water management in Europe. Climate change is not explicitly included in the text of the Water Framework Directive. However, water management under the WFD will have to deal with the challenges posed by climate change. The stepwise and cyclical approach of the WFD River Basin Management Plans (RBMPs) process makes it well suited to adaptively manage climate change impacts. In particular, the review of RBMPs every six years establishes a mechanism to prepare for and adapt to climate change.


No targets have been specified.

Related policy documents

  • Climate-ADAPT: Adaptation in EU policy sectors
    Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
  • Climate-ADAPT: Country profiles
    Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
  • DG CLIMA: Adaptation to climate change
    Adaptation means anticipating the adverse effects of climate change and taking appropriate action to prevent or minimise the damage they can cause, or taking advantage of opportunities that may arise. It has been shown that well planned, early adaptation action saves money and lives in the future. This web portal provides information on all adaptation activities of the European Commission.
  • EU Adaptation Strategy Package
    In April 2013, the European Commission adopted an EU strategy on adaptation to climate change, which has been welcomed by the EU Member States. The strategy aims to make Europe more climate-resilient. By taking a coherent approach and providing for improved coordination, it enhances the preparedness and capacity of all governance levels to respond to the impacts of climate change.


Methodology for indicator calculation

Data on Ice-breakup Dates and Freezing Dates of Lake Kallavesi, Finland, 1833-2011 provided by Finnish Environment Institute (SYKE), and data on First Ice Appearance and Final Disappearance on Danube River, at Budapest, 1876–2011 provided by Eötvös Loránd University, Institute of geography and earth sciences are displayed.


    Trend lines have been added.

    Methodology for gap filling

    Not applicable

    Methodology references

    No methodology references available.



    Methodology uncertainty

    Not applicable

    Data sets uncertainty

    Time series of lake and river ice cover are available from several lakes and rivers in Europe. It is not currently possible to provide a comprehensive picture of lake and river ice cover in Europe.

    Further information on uncertainties is provided in Section 1.7 of the EEA report on Climate change, impacts, and vulnerability in Europe 2012(

    Rationale uncertainty

    No uncertainty has been specified

    Data sources

    Other info

    DPSIR: Impact
    Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
    Indicator codes
    • CLIM 020
    Frequency of updates
    This indicator is discontinued. No more assessments will be produced.
    EEA Contact Info


    Geographic coverage

    Temporal coverage



    Filed under:
    Filed under: climate change impacts
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