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Integrating adaptation in the design of the metro of Copenhagen

Integrating adaptation in the design of the metro of Copenhagen

Climate change impact assessment has been an integrated part of the design and planning of the Copenhagen metro since the first metro line was designed in the mid-1990s. Apart from the first metro line, opened in 2002, and the extensions in the following years, which are partly subterranean, Metroselskabet, the Copenhagen metro company, is now constructing the City ring, an underground metro ring in the city centre of Copenhagen, which is scheduled to open in 2018.

The biggest planning challenge is changing projections of increasingly higher mean sea water level as a consequence of climate change, meaning that entrances, ventilation (plus other infrastructure elements) to stations and shafts near the harbour and the coastline should provide sufficient protection against storm surges.

Case Study Description


Both the subterranean part of the metro and the part above ground pose challenges related to climate change. The climate change impact assessment shows that heavy rainfall, storm surges and storms can impact the infrastructure, affecting the metro operation and passenger safety. Heavy rainfalls, storms and storm surge affect locally and are hard to predict as they can vary greatly within a short distance.

The highest water level has been identified separately for each station in order to estimate the exact level for each entrance, stairs, tunnel ventilation, ramp, technique room, shaft, elevator, and control and maintenance centre. Apart from the track, the areas and installations mentioned are the most vulnerable that may affect the operation and safety, which should be ensured. As the basis for identifying the water levels for heavy rainfall and storm surges, a 2000 year event has been used, an event which is 5 % chance of happening in the metro life (100 years). Moreover, IPCC climate projections were considered as a basis for sea level rise. These projections have changed considerably from the planning of the first metro line until now, with consequences in the design of the elevation levels, as described in the “Solutions section”.


Protect the metro system against changes in climate, particularly from heavy rainfall, storm surges and storms, that could impact the infrastructure (mainly by flooding), affecting the metro operation and passenger safety.


The elevation level of critical elements of the Copenhagen metro stations (entrance, stairs, tunnel ventilation, ramps, technique room, shaft, elevator, and control and maintenance centre) increased from approximately 2.25 m on the existing metro to approximately 2.50 m on the City ring, which is currently under construction, considering the various IPCC projections available and their evolution in time. To adapt the infrastructure of the Copenhagen metro to the future climatic changes, several other actions have been identified and incorporated in the design of the metro, for example:

  • The area around the entrances to the underground stations is designed to ensure the runoff of rainwater away from the openings. Furthermore, at some underground stations, a step has been incorporated, which requires a step up before you go down to the station.
  • All underground stations have pumping capacity to a so-called 1000 year event of rain. In the event that the tunnel is flooded, the water will automatically be pumped away.
  • Floodgates are established in 3 underground stations to secure the metro from flooding from other parts of the public transport train system.
  • In the above-ground metro system, drains are installed along the track leading the water out into the local sewer system.
  • The underground stations are protected against backflow from the city's sewerage system.
  • Installations of waterproof outer doors to the technique rooms at several stations as well as electrical and mechanical installations have been made them waterproof.
  • Technique rooms are installed with a 0.3 m raised doorstep.
  • Waterproof walls up to level 2.3 m and against waves up to level 2.55 m along the exposed above-ground metro sections.

The city of Copenhagen has a similar problem to protect its low-lying urban areas where cultural institutions, government buildings, etc. are concentrated. The Municipality of Copenhagen is therefore elaborating general plans to protect the city from storm surges and as they are being implemented, obviously they will be included in the protection of the subway. Likewise, the Municipality of Copenhagen works on plans to protect the city from the consequences of ever more extreme rainfalls in the long term, which will likewise be included in the protection of the metro.


Case mainly developed and implemented because of other policy objectives, but with significant consideration of CCA aspects

Additional Details

Stakeholder Participation

The main institutional stakeholders in this project are the city of Copenhagen, the city of Frederiksberg, the National Parliament and the Ministry of Transport. The project is implemented by Metroselskabet, a partnership of the City of Copenhagen (50 %), the Danish Government (41.7 %) and the City of Frederiksberg (8.3 %). Public consultation, based on the Environmental Impact Assessment of the project, was conducted in 2008; 200 citizens voiced concerns about the project. The approval of the final project was made by the two cities concerned in January 2009, and by the Ministry of transport in March 2009.

Success and Limiting Factors

Main success factors are: (i) Integrated approach, including flooding issues within the whole metro design concept since the feasibility stage; (ii) Building upon the experience gained during the design and operation of the previous metro lines (M1 and M2), respectively opened in 2002 and 2007; (iii) Consistency with city-wide adaptation plan to climate changes.

The main limiting factors concerns the planning and operation conditions originally established for the metro system, such as line layout and station locations, technical components, or rolling stock, to mention a few.

Costs and Benefits

Total project costs were estimated at DKK 21.3 billion in 2010. There are no separate information available about the cost of the climate-proofing measures.

The project is based on an Act on construction of a City Circle Line, passed by the national parliament in June 2007. The basic project description that served as a basis for that act is provided in the Report on the City Circle Line, prepared in 2005.

Implementation Time

Preliminary construction works started in 2010; the project should be open to service in 2019.

Life Time

100 years.

Reference Information


Lillah Lucie Emmik Sørensen
Miljø og myndighedskoordinator
Metroselskabet I/S
Metrovej 5
DK-2300 København S, Denmark
Tel.: +45 3311 1700
Mobile: +45 7242 4979

Metroselskabet, including Metroselskabet 2013 Annual report

Published in Climate ADAPT Jun 07 2016   -   Last Modified in Climate ADAPT Dec 23 2020

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