A study has found that, in a worst case scenario, European coastal cities will have to spend more than $40 billion cumulatively per year to deal with the effects of climate change.

The study by the Basque Centre for Climate Change in Spain was published in the journal Frontiers in Marine Science. It focused on 19 European coastal cities such as Istanbul, Barcelona, London, Dublin, and Rotterdam.

They looked at the impact of so-called “tail events”, which are low probability but high impact results of climate change, like a super-drought, country-wide wildfire, and so on.

“Our results show that despite their low probability of occurrence, the huge scale of the damage from them in comparison to annual average ones requires that they be very carefully considered in coastal vulnerability analysis,” the authors wrote in their study.

The estimates come from emission scenarios as per the Intergovernmental Panel on Climate Change (IPCC). By 2030, the authors say that Rotterdam tops the economic impact table, with expected annual losses of almost $240 million. By 2100, that could rise to $5.5 billion annually for Rotterdam, and billions more elsewhere.

“About two-thirds of our planet's megacities – cities with populations of more than 5 million people – are located in low-lying coastal areas so protecting these areas from rising sea levels is critical to saving lives and property,” a statement from Frontiers said. “Being so vulnerable to the impacts of climate change, coastal cities also have a major role in adapting to them.”