Hallegatte et al (2008) using Copenhagen as a case study, showed that was not highly vulnerable to storm surges and coastal floods. Man-made defences, are necessary, as without them, economic losses caused by a current 10 yr storm surge event, would reach Euros 2.5 billion Without man-made defences, sea level rise would increase coastal flood risks in a significant manner, i.e. 50 cm of sea level rise would increase by 55% the losses caused by the 120-yr event, from Euros 3 to 5 billion.
Stéphane Hallegatte ,Nicola Patmore , Olivier Mestre, Patrice Dumas, Jan Corfee Morlot, Celine Herweijer and Robert Muir, 2008. Assessing Climate Change Impacts, Sea Level Rise and Storm Surge Risk in Port Cities: A Case Study on Copenhagen, OECD Environment Working Paper, No. 3.