Indicator Specification

Marine phenology

Indicator Specification
  Indicator codes: CLIM 014
Published 08 Sep 2008 Last modified 03 Feb 2017
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Decapod abundance in the central North Sea 1950-2005 Change in colour index in southern North Sea from the 1950s until 2000s

Update planned for November 2012

Assessment versions

Published (reviewed and quality assured)
  • No published assessments


Justification for indicator selection

Phenology is the study of annually recurring life-cycle events such as the timing of migrations and flowering of plants. In the marine environment such phenology indicators would include the timing of the spring phytoplankton bloom and the peak in the abundance of other marine organisms such as the earlier appearance of dinoflagellates associated with summer stratified conditions. Change in phenology is one of the key indicators of the impacts of climate change on biological populations. Because marine species have different sensitivities to changes in temperature, these changes may lead to large shifts in the marine food web that can ultimately affect the food available to fish, birds or marine mammals.
In the North Sea, many species are appearing earlier in their normal seasonal cycles while others are not. This has led to a decoupling of species relationships and changes in food-web structures (Edwards and Richardson, 2004). Such changes in plankton have been strongly implicated in worsening the decline in North Sea cod stocks, caused initially by over-fishing (Beaugrand et al., 2003), and have contributed to changing other fish populations (sand-eels) that are an essential food source for seabirds (Frederiksen et al., 2006).
The southern North Sea has been identified as being particular vulnerable to phenology changes (Edwards, Woo and Richardson, in prep.). Phenology changes have been related to the degree and speed of regional climate change. For example, the southern North Sea is warming faster than other regions in the North East Atlantic and is where phenological movement has been much more pronounced.

Scientific references

  • No rationale references available

Indicator definition

  • Decapod abundance in the central North Sea 1950-2005
  • Change in colour index in southern North Sea from the 1950s until 2000s



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:


No targets have been specified

Related policy documents

No related policy documents have been specified



Methodology for indicator calculation

Methodology for gap filling

Methodology references

No methodology references available.


Data specifications

EEA data references

  • No datasets have been specified here.

External data references

Data sources in latest figures



Methodology uncertainty

Data sets uncertainty

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

Trine Christiansen


European Environment Agency (EEA)


Indicator code
CLIM 014
Version id: 1


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



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