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BaltCICA workshop in Helsinki, 8.6.2010
Climate change and sea level rise in the Helsinki Metropolitan area
The Centre for Urban and Regional Studies (Aalto University) organised a BaltCICA workshop in Helsinki on 8th of June that brought together different sectors from three cities in the Metropolitan region. The workshop focused on sea level rise as a consequence of climate change and to what extent it poses a threat to the Metropolitan region. Stakeholders also discussed future scenarios for the region, and outlined visions for the region in 2100.
Sea level rise as a consequence of climate change: How big a threat to the region?
Sea levels are estimated to rise as a result of climate change, as much as 1.9 metres during the 21st century, if one considers the worst case scenario (Vermeer & Rahmstorf 2009). Even the more conservative projections of a 30 centimetre rise can have significant consequences to low lying areas around the Baltic Sea and its cities. Flooding resulting from the rise of sea levels within the Baltic Sea is considered to be an outcome of several drivers (Kahma 2009). Amongst the long term factors that affect flooding due to sea level rise are land uplift of the coast line and the water balance of the Baltic Sea, whereas the short term drivers include salinity of the water, wind conditions and changes in air pressure. The flooding experienced in 2005 within Helsinki was a good example of the vulnerability of the city to flooding resulting from sea level rise.
Three expert speakers on this topic had been invited to talk about the latest research findings on sea level rise related to climate change. Professor John Moore (University of Lapland and Beijing Normal University) discussed the findings related to ice sheet melting and how that affects sea levels globally. Considering the existing evidence, Prof Moore concluded that sea levels are likely to exceed 1 metre before 2100 but unlikely to exceed 2 metres by 2100. Professor Martin Vermeer (Aalto University) discussed the complexities of measuring and modelling sea level rise, highlighting to the participants the uncertainties involved in research on complex natural systems.
Professor Kimmo Kahma (Finnish Meteorological Institute) focused on the likely rises in sea level on the coast of Finland. According to Professor Kahma, the melting of the Western-Antarctica is likely to have the severest effect on the sea levels in the Baltic Sea but that this is likely to take thousands of years. Current guidelines for building height minimum (260cm) in Helsinki were considered to adequate. However, no irreversible decisions affecting the long term future are recommended to be made. Overall, the speakers highlighted the issue of rapidly moving research field within which new studies emerge constantly, and that more reliable and update information is likely to be available in a few years time.
Future visions for the metropolitan region?
The City of Helsinki and the HSY Helsinki Region Environmental Services Authority aim to identify and implement adaptation measures within the metropolitan region as part of the BaltCICA-project, and this workshop supported this process. The participants of the workshop had been sent four possible future scenarios for the Metropolitan region in advance, and these scenarios were discussed in the second half of the workshop. The four scenarios broadly outlined the possible futures when 1) no action is taken to adapt, 2) emphasis is placed on protecting assets from sea level rise, 3) accommodating measures are taken to adapt to sea level rise and finally 4) retreating from areas that are threatened by sea level rise.
The small groups discussed the positive and negative aspects of each scenario, and all groups were unanimous in that it is unlikely that no adaptation measures will be taken. All groups favoured the second and third scenario of adaptation with a combination of large and small measures, and this was also apparent when the groups begun to outline their own vision for the Metropolitan region. The Metropolitan region in 2100, as visioned by the participants, has combined both mitigation and adaptation measures, and measures have been taken to protect the city centre as it is now. The trend of building in the proximity of the coast line is likely to continue but technological solutions are likely to enable new innovative solutions.
Kahma, Kimmo 2009. Merivesitulvat. Tulva- ja patopäivät. Suomen ympäristökeskus. 13.-14. 10. 2009. Helsinki.
Vermeer, M. & Rahmstof, S. 2009. Global sea
level linked to global temperature. Proceedings of the National Academy
of Sciences. December 22, 2009 vol. 106 no. 51 21527-21532
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