Sea surface temperature

Assessment versions

Published (reviewed and quality assured)

• Sea surface temperature (CLIM 013) - Assessment published Nov 2012

Justification for indicator selection

Sea surface temperature (SST) is relevant for monitoring of climate change because it reflects regional changes in ocean temperature, whereas OHC is estimated globally. SST is closely linked to one of the strongest drivers of climate in western Europe, the ocean circulation that is known as Atlantic Meridional Overturning Circulation (MOC) or alternatively as the great conveyor belt. This circulation carries warm upper waters north in the Gulf Stream and returns cold deep waters south. It is widely accepted that the MOC is an important driver of low-frequency variations in sea surface temperature on the time scale of several decades. It is also widely accepted that the NAO-index (a proxy of atmospheric variability) plays a key role in forcing variations in MOC as well as the northward extent of the Gulf Stream.

The MOC sensitivity to greenhouse warming remains a subject of much scientific debate, largely because its large natural variability and the scarcity of observations makes trend detection very difficult.

One of the most visible ramifications of increased temperature in the ocean is the reduced area of sea ice coverage in the Arctic polar region. There is an accumulating body of evidence suggesting that many marine ecosystems are also sensitive to changes in SST. For example, the spread of oxygen-free areas (so called dead zones) in the Baltic Sea in the past 1 000 years was strongly linked to above-average SST.

Scientific references:

• IPCC, 2007: Cimate Change: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Solomon, S.; Qin, D.; Manning, M.; Chen, Z.; Marquis, M.; Averyt, K. B.; Tignor M. and Miller H. L. (eds.), Cambridge University Press, Cambridge, UK.

Indicator definition

• Annual average sea surface temperature anomaly in different European seas

• Mean annual sea surface temperature trend in European seas

Units

• °C

• °C/yr

Policy context and targets

Context description

Targets

No targets have been specified.

Related policy documents

• Climate-ADAPT: Mainstreaming adaptation in EU sector policies
  Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
• Climate-ADAPT: National adaptation strategies
  Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
• DG Climate Action: What is the EU doing about climate change?
  Activities of the EU regarding climate change (both mitigation and adaptation)
• White paper - Adapting to climate change: towards a European framework for action
  EU framework for adaptation to climate change, leading to a comprehensive EU adaptation strategy by 2013

Methodology

Methodology for indicator calculation

Sea surface temperature datasets stem from the Hadley Centre (HADISST1 (global)), MOON-ENEA (Mediterranean Sea), and Bundesamt für Seeschifffahrt und Hydrographie (Baltic and North Seas), and MyOcean.

Methodology for gap filling

Not applicable

Methodology references

• Frankignoul and Kestenare (2005) Observed Atlantic SST anomaly impact on the NAO: an update Journal of Climate 18(19), 4089–4094. doi:10.1175/JCLI3523.1

Data specifications

EEA data references

• No datasets have been specified here.

External data references

• Global Ocean OSTIA Sea Surface Temperature and Sea Ice Reanalysis
• Sea surface temperature - Mediterranean Sea
• Sea surface temperature - Baltic and North Seas
• HadISST1 - Global sea ice and Sea Surface Temperature analyses

Data sources in latest figures

Uncertainties

Methodology uncertainty

Not applicable

Data sets uncertainty

In general, changes related to the physical and chemical marine environment are better documented than biological changes because links between cause and effect are better understood and often time series of observations are longer. For example, systematic observations of both sea-level and sea surface temperature were started around 1880 and are today complemented by observations from space that have high resolution in time and geographical coverage and by Argo floats that also automatically measure temperature and salinity below the ocean surface.

Further information on uncertainties is provided in Section 1.7 of the EEA report on Climate change, impacts, and vulnerability in Europe 2012 (http://www.eea.europa.eu/publications/climate-impacts-and-vulnerability-2012/)

Rationale uncertainty

No uncertainty has been specified