DINAS-COASTS DG research project results show impacts increasing significantly without adaptation: in the 2080s under the A2 SRES scenario, it is estimated that around 2 000 to 17 000 km² of land in Europe could be permanently lost, leading to 0.1 to 1.3 million people in Europe experiencing coastal flooding each year, depending on the climate sensitivity. The economic costs of these events are estimated in the range of 12 to 18 billion euro/year for Europe in 2080 (current prices). Large areas of coastal wetlands are also threatened, with the highest relative losses on the Mediterranean and Baltic coasts.
ABI (2006) estimates that a 40 cm rise in sea levels will put an extra 130 000 properties at risk of flooding in the United Kingdom. In total 400 000 properties will be at risk, up nearly 50 % on the current number. Without improvements to existing flood defences, the costs of a major coastal flood could soar by 400 % to as much as GBP 16 billion. Essential services and lives will also be at risk, e.g. 15 % of fire and ambulance stations and 12 % of hospitals and schools are in flood-risk areas. The elderly will be particularly affected as the number living on, or moving to, the coast is well above the national average.
Using the same climate and sea-level projection as above (A2 scenario in the 2080s), with hard adaptation measures (dike building and beach nourishment) included, the DINAS-COAST Consortium and the PESETA project suggest that the land loss falls to less than 1 000 km² and the economic costs to around 1 billion euro/year. The adaptation costs (mainly coast protection with dikes) are estimated at some 1 billion euro/year, but these achieve considerable reductions in the residual damage.
ABI (2006) also estimates that spending around GBP 6-8.5 billion on improving coastal defences would have a substantial impact on damages, both now and in the future. In other words, they would virtually pay for themselves in a single incident, ignoring the wider social and economic costs that arise from regional damage. But of course sea defences do not simply operate on a single occasion: in reality defences would prevent many less severe storm surges from causing damage. Typically this type of capital investment may deliver benefits over its lifetime worth seven times the cost. The benefits from this investment will be even greater if the frequency of storms increases in line with predictions.
Recent work (OECD, 2008) assessed exposure to a 1 in 100 year flood event, looking at population and asset value exposed now and with sea-level rise in 2100 for the following cities: Amsterdam, Rotterdam, Hamburg, London, Copenhagen, Helsinki, Marseille-Aix-en- Provence, Athens, Napoli, Lisbon, Porto, Barcelona, Stockholm, and Glasgow. For these cities, the exposed population increases from 2.3 million to 4.0 million, and the exposed assets from EUR 240 to EUR 1 400 billion (the values are dominated by London, Amsterdam, and Rotterdam).