With sea level rise, damage costs rise even faster: study

The damage costs from climate impacts for coastal regions consistently increase at a higher rate than the sea-level rise itself, according to a new study.
Scientists have developed a method to quantify monetary losses from coastal floods under sea-level rise.
The method translates the occurrence probability of flood events into the probability of inundation damage.
Expected regional sea level rise is taken into account by separating two components, namely the increasing number of events and the increasing severity of each one, researchers said.
"When sea levels rise, damage costs rise even faster, our analyses show," said Markus Boettle from Potsdam Institute for Climate Impact Research (PIK) in Germany.

Rising sea levels as a major impact of climate change pose a risk for coastal regions - the mean regional sea level rise takes effect by more frequent and more intense coastal flood events.

"At the same time, the severity of flood impacts is not only determined by environmental factors, but also to a significant extent by human decisions - flood defence measures can counteract the increasing flood risk," said Boettle.
"Our study illustrates that the complexity of climate change, adaptation, and flood damage can be disentangled by surprisingly simple mathematical functions to provide estimates of the average annual costs of sea-level rise over a longer time period," Boettle said.

Expected regional sea level rise is taken into account by separating two components, namely the increasing number of events and the increasing severity of each one.
"Our equations basically work in Mumbai, New York, Hamburg - Pacific, Atlantic, or North Sea. In any location worldwide the same simple and universal expressions hold true," said Jurgen Kropp from PIK.
In Copenhagen in Denmark, researchers found that a moderate mean sea level rise of 11 centimetres until mid-century would in the same period double economic losses in this city, given no action is taken.
"Even when temperatures stabilise, sea levels will continue to rise and shape our coastlines for future generations," said Diego Rybski from PIK.

"So, additional preventive measures need to be considered in addition to the mitigation of greenhouse gas emissions, to help coastal regions especially in transition and developing countries to adapt and to limit damage costs," said Rybski.
The findings were published in Natural Hazards and the Earth System.