Baltic Sea region air temperature likely to achieve 3ºC to 5ºC increase this century

Helsinki, 7 March (HELCOM Information Service) – The projections for future climate change in the Baltic Sea region, with all of their caveats and uncertainties, indicate that atmospheric temperatures will continue to rise during the course of the 21st century in every sub-region of the Baltic Sea region, according to a Thematic Assessment on Climate Change in the Baltic Sea Area, adopted today at the annual Meeting of the Helsinki Commission by the representatives of the Baltic Sea coastal countries. The assessment will serve as a background document to the HELCOM Baltic Sea Action Plan to further reduce pollution to the sea and restore its good ecological status, which is slated to be adopted at the HELCOM Ministerial Meeting in November 2007.

This new report is based on the Assessment of Climate Change for the Baltic Sea Basin Project (The BACC Project), which integrates available knowledge of historical, current, and expected future climate change. The BACC Project is a joint venture of the BALTEX (Baltic Sea Experiment) Program and HELCOM as an example of a dialogue between the scientific community and environmental policy makers. The unique feature of BACC is the combination of evidence on climate change and related impacts on marine, freshwater, and terrestrial ecosystems in the Baltic Sea region, which encompasses the entire region in northern Europe from which water drains into the Baltic Sea. It is the first systematic scientific effort for assessing climate change in a European region. More than 80 scientists from 12 countries have contributed on a voluntary basis.

According to the assessment, the warming trend for the mean surface air temperature of the entire globe was about 0.05°C/decade from 1861–2000, while the trend for respective mean air temperature in the Baltic Sea region has been somewhat larger, 0.08°C/decade. This warming trend has been reflected in a decrease in the number of very cold days during winter as well as a decrease in the duration of the ice cover and its thickness in many rivers and lakes, particularly in the eastern and southeastern Baltic Sea region. In addition, the length of the frost-free season has increased and an increasing length of the growing season in the Baltic Sea region has been observed during this period.

Based on available regional modelling studies, a warming of the mean annual air temperature near the surface in the order of 3ºC to 5ºC is projected as an average for the total Baltic Sea region during this century. “These figures, however, do not reflect the full range of uncertainties in global climate model projections. Seasonally, the largest part of this warming would occur to the east and north of the Baltic Sea during winter months and to the south of the Baltic Sea during summer months,” says Dr. Hans-Jörg Isemer, Head of the International BALTEX Secretariat, located at the GKSS Research Centre in Geesthacht, Germany. “A warming of such magnitude would lead to a lengthening of the growing season, by as much as 20 days to 50 days for northern areas and 30 days to 90 days for southern areas by the late 21st century, depending on the different emissions scenarios used,” notes Dr. Isemer.

In the Baltic Sea, there has also been a general tendency toward milder sea-ice conditions during the past century; this is reflected in time series data on the maximum annual extent of sea ice and the length of the ice season in the Baltic Sea. The largest change has been in the length of the ice season, which has decreased by 14–44 days over the past century, mainly due to earlier ice break-up. On the basis of the ice extent, the shift towards a warmer climate took place in the latter half of the 19th century. During the past ten years, all ice winters have been average, mild, or extremely mild.

The mean sea surface temperature of the Baltic Sea is projected to increaseby between 2ºC and 4ºC, depending on the model and scenario used, resulting in a marked decrease in the extent of ice in the sea. The projected decrease of ice cover by the end of the 21st century is dramatic, with the Bothnian Sea, large areas of the Gulf of Finland and the Gulf of Riga, and the outer parts of the southwestern archipelago of Finland becoming, on average, ice free. The length of the ice season would decrease by 1–2 months in the northern parts of the Baltic Sea and by 2–3 months in the central parts.

Because the mitigation of climate change is a global challenge, support for the implementation of national, EU, and particularly global initiatives to reduce emissions of greenhouse gases (including the European Climate Change Programme, the UN Framework Convention on Climate Change, and the Kyoto Protocol) is necessary.

The assessment suggests that adaptation to climate change will need to be regional and local and should aim to reduce the negative effects of climate change. In order to balance management decisions between the precautionary principle and scientific evidence, a robust basis of environmental observations and model projections should be developed to support policy-making and management.

In relation to the programmes of HELCOM, it is clear that climate change will affect the attainment of all four HELCOM goals for the Baltic Sea Action Plan: (1) the Baltic Sea unaffected by eutrophication; (2) a favourable status of Baltic Sea biodiversity; (3) Baltic Sea life undisturbed by hazardous substances; and (4) maritime activities carried out in an environmentally friendly way. The greatest effect would be on biodiversity, but clear effects could also be anticipated on eutrophication.

“The HELCOM strategy in relation to climate change should aim to limit or mitigate adverse impacts as well as to enhance the resilience of the Baltic marine environment by improving its capacity to cope with the stress of climate change,” says Juha-Markku Leppänen, HELCOM Professional Secretary. It is thus necessary to continue to improve measures:

-                      to mitigate eutrophication by intensifying the reduction of waterborne and airborne nutrient inputs;

-                      to continue and intensify measures to reduce inputs of heavy metals and persistent or hazardous organic pollutants;

-                      to reduce emissions (both from fuel combustion and from ship antifouling treatments) from maritime transport and to prevent ballast water releases;

-                      to enhance the protection of marine and coastal landscapes and habitats and, particularly, the conservation of native Baltic species.

The implementation of the strategic Baltic Sea Action Plan, which is currently being drafted by HELCOM, will provide a basis for enhancing the resiliency and adaptive capacity of the Baltic Sea environment, adds Leppänen.

Note to Editors: 

The Baltic Marine Environment Protection Commission, more usually known as the Helsinki Commission, or HELCOM, is an intergovernmental organisation of all the nine Baltic Sea countries and the EU which works to protect the marine environment of the Baltic Sea from all sources of pollution. 

HELCOM is the governing body of the "Convention on the Protection of the Marine Environment of the Baltic Sea Area," known as the Helsinki Convention.

Follow-up: Thematic Assessment on Climate Change in the Baltic Sea Area

For more information, please contact:

Mr. Nikolay Vlasov

Information Secretary

HELCOM

Tel: +358 (0)207 412 635

Fax: +358 (0)207 412 639

E-mail: nikolay.vlasov@helcom