Natural solutions cost up to 62% less as protection for coastal cities

Protecting coastal cities using natural ecosystems, such as sandbars, dunes, mangroves, and coral reefs, can be up to 62 percent less expensive than constructing conventional engineering projects. A study by the Boticário Group Foundation for Nature Conservation, in collaboration with the Maré de Ciência Program at Federal University of São Paulo and Kralingen Consultoria, found that nature-based solutions can offer significant cost savings for coastal protection in Brazil.

The analysis examined six coastal cities in Brazil and compared the economic value of nature-based solutions to traditional gray infrastructure. The results showed that in areas with ample space, the restoration of coastal ecosystems proved to be more financially advantageous. For instance, in Copacabana Beach, Rio de Janeiro, the implementation and maintenance of a sandbar would cost 38 percent of the estimated investment for rigid structures, such as low walls and rockfill.

However, in more urbanized coastal areas, where space is limited, the costs of implementing and maintaining natural solutions can exceed those of gray infrastructure. For example, at Armação Beach in Florianópolis, where properties need to be purchased to enable ecosystem restoration, nature-based solutions would account for 87.1 percent of the cost of a hybrid engineering alternative.

The economic losses due to the destruction of coastal environments can be substantial. In Natal, the loss of natural beaches and dunes has cost public works BRL 145 million for rebuilding and maintaining rigid coastal infrastructure from 2011 to 2025, with additional tourism losses amounting to BRL 121 million. In Salinópolis, Pará state, the loss of mangrove forests has led to an estimated economic loss of BRL 76 million over the past 30 years, with 72 percent of the costs associated with home damage.

On average, the absence of natural protection results in an annual loss of BRL 2,540 per home due to flooding. The study emphasizes that the importance of preserving ecosystems becomes evident only when they are lost, as their protective services significantly reduce the economic impact of coastal degradation.