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. For this scope, Metroselskabet, the Copenhagen metro company, developed a climate change adaptation strategy, which supports the integration of adaptation aspects since the planning and dimensioning phase of the metro system. Apart from the first metro line, opened in 2002, and related extensions in following years, in 2019 Metroselskabet put into operation a new city circle line (Cityringen line M3/M4). The new metro line is 15.5 km long and includes a total of 17 stations. With this new line, public transport gained a significant boost and the number of passengers using the metro raised from 64.7 million in 2018 to 78.8 million in 2019.

The most important climate change operational and planning challenges for Copenhagen metro are related to the expected increase in mean sea level causing more severe flooding by sea surges and higher occurrence of extreme weather events. These challenges imply the need for equipping metro entrances, ventilation systems to metro stations (plus other infrastructure elements) and metro shafts with measures protecting them against these events. As climate change projections has changed since the first metro line was put into operation, gradually higher requirements ensuring climate proof metro design and operation had to be adopted.