The reforestation of Rio de Janeiro bay shows the power of mangroves in mitigating climate disasters

RIO DE JANEIRO (AP) — At the back of Rio de Janeiro’s polluted Guanabara Bay, thousands of mangroves reach nearly 4 meters high in a previously deforested area.

The 30,000 trees, planted by the non-profit organization Instituto Mar Urbano over four years in the Guapimirim environmental protection area, are an example for cities seeking natural ways to improve climate resilience.

Such ecosystems are vital for protecting against floods that have become increasingly frequent around the world. The state of Rio Grande do Sul in southern Brazil is still reeling of a devastating flood earlier this month that caused havoc and claimed liveswith the waters far from falling to normal levels.

Mangroves slow the advance of seawater into riverbeds during storms by absorbing it, and they protect the land by stabilizing soil that might otherwise wash away. They also act as carbon sinks. The reforestation of Rio Bay has improved the cleanliness of the waters that are breeding grounds for marine species. The crabs returned, providing extra income for local collectors who helped plant the trees.

“Planting a tree in this mangrove is an act of environmental recovery and also an act of fighting climate change,” Ricardo Gomes, director of the non-profit organization, told the Associated Press on Thursday. “Today we can be sad, because everything that was lost (in southern Brazil), everything that was destroyed. But we have never had so much knowledge, so much technology and resources to recover our environment.”

The lack of mangroves was not the cause of the floods in the capital of Rio Grande do Sul, Porto Alegre, which is next to a lagoon. The flooding resulted in much of the water flowing down rivers into the area.

The coastal risk map created by Climate Central, a nonprofit scientific research group, predicts that areas west and north of Porto Alegre will be underwater by 2100. In Rio, it shows two large areas at the back of its bay – one of which includes the Guapirimim River. protected area — will be underwater by 2050. This highlights the need for measures to mitigate seawater intrusion.

Natural vegetation like that of Guapimirim “is like a real sponge,” preventing or mitigating floods by reducing water energy, said Mauricio Barbosa Muniz, manager of a reserve at the Brazilian federal agency Instituto Chico Mendes de Conservação da Biodiversidade. The region’s vegetation protects 1 million residents of the city of São Gonçalo, in the metropolitan region of Rio, and others.

“In places that have been irregularly occupied, such as cities, it is possible to restore these areas and create resilient human settlements prepared for the effects of climate change,” said Muniz.

Since 2000, flood-related disasters across the planet have increased by 134% over the previous two decades, according to a 2021 report from the World Meteorological Organization.

Environmentalists claim that the loss of natural vegetation due to agriculture and livestock farming in Rio Grande do Sul has increased the floods. A recent study by MapBiomas, a network that includes non-profit organizations, universities and start-ups, says that the Brazilian state lost 22% of its native vegetation between 1985 and 2022, equivalent to an area larger than the US state of Maryland .

Federal, state and municipal authorities appear to be in agreement since the tragedy that a major reforestation effort will be necessary in Rio Grande do Sul, but the scope of investment and specific initiatives have not yet been announced.

____ Savarese reported from São Paulo.