Indicator Specification

Arctic and Baltic Sea ice

Indicator Specification
  Indicator codes: CLIM 010
Published 19 Nov 2012 Last modified 04 Dec 2019
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This is an old version, kept for reference only.

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This page was archived on 20 Dec 2016 with reason: Other (New version data-and-maps/indicators/arctic-sea-ice-2 was published)
Trend in Arctic sea ice extent in March and September Maximum ice cover extent in the Baltic Sea Projected changes in Nothern Hemisphere sea ice extent

Assessment versions

Published (reviewed and quality assured)
  • No published assessments


Justification for indicator selection

Observed changes in the extent of Arctic Sea ice provide early evidence of global climate warming. Sea ice is a habitat for endemic species in a unique ecosystem, and it also plays an important role for the pelagic ecosystem in the open ocean. Species specialised to live in conditions dominated by sea ice are affected and this can also affect use of living natural resources. Reduced polar sea ice will speed up global warming and is expected to affect ocean circulation and weather patterns across northern Europe.

The projected loss of sea ice may offer new economic opportunities for oil and gas exploration, shipping, tourism and some types of fishery. Most of these activities would increase pressure on, and risks to, the Arctic environment.

Scientific references

Indicator definition

  • Trend in Arctic sea ice extent in March and September
  • Maximum ice cover extent in the Baltic Sea
  • Projected changes in Nothern Hemisphere sea ice extent


Area (km²)

Policy context and targets

Context description

In April 2013 the European Commission presented the EU Adaptation Strategy Package ( This package consists of the EU Strategy on adaptation to climate change /* COM/2013/0216 final */ and a number of supporting documents. One of the objectives of the EU Adaptation Strategy is Better informed decision-making, which should occur through Bridging the knowledge gap and Further developing Climate-ADAPT as the ‘one-stop shop’ for adaptation information in Europe. Further objectives include Promoting action by Member States and Climate-proofing EU action: promoting adaptation in key vulnerable sectors. Many EU Member States have already taken action, such as by adopting national adaptation strategies, and several have also prepared action plans on climate change adaptation.

The European Commission and the European Environment Agency have developed the European Climate Adaptation Platform (Climate-ADAPT, to share knowledge on observed and projected climate change and its impacts on environmental and social systems and on human health; on relevant research; on EU, national and subnational adaptation strategies and plans; and on adaptation case studies.


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.

Key policy question

What is the trend in the extent of Arctic and Baltic Sea ice?



Methodology for indicator calculation

Input data was available from the EUMETSAT OSI SAF reanalysis project, in which a consistent time series of daily, gridded data for sea ice concentration is made from the passive microwave sensors SMMR and SSM/I data, monthly aggregated sea ice products are generated by CryoClim.

The annual maximum ice extent in the Baltic Sea was estimated utilizing the material of the Finnish operational ice service from the winters of 1945-1995 and information collected by Prof. Jurva from the winters of 1720-1940. The latter originated from various sources, including observations at lighthouses, old newspapers, records on travel on ice,scientific articles, and air temperature data from Stockholm and Helsinki.

Projections for Northern Hemisphere sea ice extent were derived from the CMIP5 ensemble experiment.

The graphs show the data as delivered; Trend lines were added.

Methodology for gap filling

Not applicable

Methodology references


Data specifications

EEA data references

  • No datasets have been specified here.

External data references

Data sources in latest figures



Methodology uncertainty

Not applicable

Data sets uncertainty

Data on the cryosphere vary significantly with regard to availability and quality. Snow and ice cover have been monitored globally since satellite measurements started in the 1970s. Improvements in technology allow for more detailed observations and higher resolution.

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

Further work

Short term work

Work specified here requires to be completed within 1 year from now.

Long term work

Work specified here will require more than 1 year (from now) to be completed.

General metadata

Responsibility and ownership

EEA Contact Info

Hans-Martin Füssel


European Environment Agency (EEA)


Indicator code
CLIM 010
Version id: 2

Frequency of updates

Updates are scheduled once per year


DPSIR: Impact
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)


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