Rising sea levels carry gigantic economic costs

Rising global temperatures are no longer a theoretical bogeyman. The associated rise in sea levels is a direct threat to buildings and infrastructure in coastal cities. Tangible damage is already being observed today, with the total cost, according to analysts, potentially reaching as much as $3 billion by 2100.

Construction disaster in Alexandria

The number of collapsed buildings in the region of the Egyptian port of Alexandria, located on the southern Mediterranean coast, has doubled over the past two decades, according to a paper published in the February issue of Earth’s Future magazine. The researchers analyzed statistics of building disasters along the 70-kilometer-long stretch of coastline and concluded that the cause of the phenomenon is rising sea levels coupled with continuous erosion of the coastline.

Intensive urbanization of the seacoast and inefficient land use disrupt sedimentary processes, disturbing the geological structure. This makes it easier for rising seawater to penetrate aquifers, which in turn alters the mechanical properties of soils and strains the foundations of buildings. An Egyptian analysis shows that more than 7,000 architectural structures in the dry, low-lying region of Alexandria are directly threatened – among them are valuable monuments of the ancient metropolis.

How much will sea level rise cost?

The problem of rising sea and ocean levels is global in scope and involves more than just the risk of compromised building foundations. Coastal cities around the world are also threatened by seawater inundation and associated displacement, transportation disruption and infrastructure crises. How will this translate into the economy?

In 2022. operating at the University of Chicago in the US, the Climate Impact Lab has developed a model of the potential damage from climate change-induced sea level rise. It shows that the global economy will lose between $2.9 trillion and $3.4 trillion by the end of the 21st century if the goals of the Paris Agreement are not met. annually. Negative changes are expected to affect up to 649,000 square ^kilometers of land area, more than 60 percent of which is located in the tropics. The greatest damage is forecast in Asia, the world’s most densely populated continent.

Europe’s most vulnerable coasts

In Europe, more than 200 million people live in the zone up to 50 km from the sea coast. These regions generate 40 percent of GDP and are involved in 75 percent of international maritime transport. It is hardly surprising that the consistent rise in sea levels is already causing serious concern among planners and economists.

In January 2024. The journal Scientific Reports published an interesting analysis by Dutch scientists led by Ignasi Cortés Arbués. On the basis of 155 floods that hit Europe between 1995 and 2016, they managed to develop a model of potential economic losses in various regions of the continent in the event of a black scenario of further increases in global temperature. It shows that coastal areas in the EU and the UK will lose between 9.5 and 20.8 percent of GDP, with cumulative losses of up to 871.8 billion euros (in 2015 prices) before 2100.

The Italian regions of Venice (a loss of 20.84 percent of regional GDP) and Emilia-Romagna (10.16 percent) are forecast to suffer the most damage. Its entire economy is expected to lose 4.43 percent of GDP. In Poland, rising sea levels could result in a GDP loss of a modest 0.8 percent, but for the West Pomeranian and Pomeranian Voivodeships the forecasts are very pessimistic, with regional GDP declines of 12.10 and 9.58 percent, respectively. Europe’s most economically vulnerable regions also include the west coast of France, the Belgian coast and Central Greece.

In terms of the structure of losses by economic sector, rising sea levels will leave the greatest mark on public services, agriculture and industry. The construction and logistics sectors, on the other hand, are likely to benefit, and will be key to the recovery process. The Ignasi Cortés Arbués team also suggests that inland regions may benefit from the coast’s problems, as they will begin to take over some of its economic and social functions.

What can be done to limit the damage from rising sea levels?

However, the scientists’ black scenarios are not created to scare the public, but to motivate change. According to Climate Impact Lab, we can proactively protect ourselves from expected flooding by building breakwaters and dikes in low-lying coastal cities. Preventive relocation of structures and residential neighborhoods away from the shoreline also seems reasonable. Such measures could reduce the damage caused by rising sea levels from $3 trillion to $400-520 billion.

However, Egyptian scientists warn of the negative effects of “hard protection” of the coasts, suggesting that it negatively affects the health of natural ecosystems. In this regard, investments in the restoration of dunes, wetlands and beaches seem to be a better solution, although unfortunately they are costly and not possible everywhere.

The World Economic Forum cites other ways to prepare for rising sea levels that are already being implemented around the world. New Zealand’s capital Wellington, located right on the coast of the windy Cook Strait, has created its digital twin. The virtual model of the city allows decision-makers to assess the threat of flooding in real time and take appropriate countermeasures. And it is worth mentioning that New Zealand society has already experienced losses of $840 million between 2007 and 2017 as a result of floods and droughts caused by climate change.

In the Maldives, authorities have responded to rising sea levels by developing a nature-inspired Drifting City project. This lowest-lying country in the world could lose up to 80 percent of its land area by 2050. The new city has been planned to meet climate challenges and support environmental protection – canals dominate the city, and automobile traffic is banned. The entire project will be completed in 2027 and will provide a roof over the heads of 20,000 people. individuals. A similar project called Oceanix Busan is being developed in South Korea and will accommodate 12,000. residents. Drifting platforms with a wax slice structure additionally provide a way to restore coral reefs and associated ecosystems.

The Netherlands began developing the Sand Motor project 10 years ago, which involves erecting a dike to stem marine invasion. Created from 20 million^{cubic meters of} sand, the scythe-shaped peninsula is meant to protect the coast from floods and counteract the destruction of natural habitats. Similar nature-based solutions are being implemented in San Francisco, using modern bioengineering to build artificial reefs, expand the extent of salt marshes or terrace wetland structures.

There is no doubt that the annual sea level rise of about 3.5 mm requires coastal cities to urgently redefine their approach to urban planning. The significant economic costs resulting from coastal flooding are only part of the problem. Indeed, the forced displacement of entire communities inland could exacerbate social conflicts and disrupt the global economic and political balance.