The shorelines that global climate change will inundate

A new global model predicts the extent, as well as the devastating socio-economic consequences, of future coastal flooding triggered by global climate change, with Asia, West Africa and Egypt in the worst of those scenarios decades from now.

The study has been carried out by the team of Ian Young and Ebru Kirezci, both from the University of Melbourne in Australia.

The study authors set out to make as accurate a forecast as possible of the annual costs and number of people affected by temporary coastal flooding around the world as sea levels rise. The research results indicate that flooding will disproportionately affect developing nations, given their reduced ability to afford improvements to their coastal defenses and given their geographic vulnerability.

Specifically, many of these developing nations will likely suffer annual damages costing more than five percent of their national Gross Domestic Product (GDP) if adaptation measures for coastal defenses are not taken to mitigate the impact of extreme coastal flooding. .

By contrast, almost all developed nations will suffer annual damage of less than 3 percent of national GDP due to their ability to adopt adaptive measures for their coastal defense systems.

Adaptation measures for coastal defense systems include raising or building dikes or retaining walls as sea level rises, and natural interventions such as drainage and sand dune improvements or mangrove plantations.

Floods like this one in 2014 in Norfolk, Virginia, United States, will become more frequent in coastal regions around the world due to global climate change. (Photo: NOAA)

The researchers created a database to model and analyze projected extreme coastal flooding in more than 9,000 locations for the years 2050 and 2100.

The modeling predicted the most severe impacts by the year 2100 in Asia, West Africa and Egypt. Among the nations and regions likely to be most affected. Also included are Suriname, Vietnam, Macao (Special Administrative Region of China), Myanmar (Burma), Bangladesh, Kuwait, Mauritania, Guyana, Guinea-Bissau, Egypt, and Malaysia.

Coastal flooding can be caused by high tides, very strong waves, rising sea levels caused by global warming, or a storm surge (rising water caused by wind from a storm). It is even worse when more than one of these phenomena coincide at the same time.

Without adaptation measures, simulations predict that the number of people affected by extreme coastal flooding could increase from 34 million people a year in 2015 to 246 million people in 2100. The projected annual global cost of damage from coastal flooding extremes could go from 0.3% of world GDP in 2015 to 2.9% in 2100.

However, if coastal defense measures are adjusted to the projected rise in sea levels, by 2100 the number of people affected would be about 119 million per year, and the projected annual global cost would be reduced almost three times, to 1 .1% of GDP. The researchers caution, however, that raising the money needed to pay for these reforms will be a huge challenge.

The study is titled “Global-scale analysis of socioeconomic impacts of coastal flooding over the 21st century”. And it has been published in the academic journal Frontiers in Marine Science. (Fountain: NCYT by Amazings)