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Lake and river ice cover (CLIM 020) - Assessment published Nov 2012

Indicator Assessment Created 12 Nov 2012 Published 20 Nov 2012 Last modified 20 Nov 2012, 12:30 PM
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Generic metadata


Climate change Climate change (Primary topic)

Water Water

climate change impacts
DPSIR: Impact
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • CLIM 020
Temporal coverage:
Geographic coverage:
Võrtsjärv, Finland, Saimaa, Hungary, Meuse, Rhine, Danube River

Key policy question: What is the trend in the ice cover of rivers and lakes across Europe?

Key messages

  • 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.

Key assessment

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.

Data sources

More information about this indicator

See this indicator specification for more details.

Contacts and ownership

EEA Contact Info

Peter Kristensen


EEA Management Plan

2012 2.0.1 (note: EEA internal system)


Frequency of updates

Updates are scheduled every 4 years in October-December (Q4)

Related content

Related briefings

Filed under:


European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Phone: +45 3336 7100