On the coast of typhoon-prone Philippines, mangroves resembling upside-down tree roots help to protect people from storms and act as a nursery for animals like fish and clams.
When the severe Typhoon Rai hit Siargao Island in 2021, for example, more than 8,000 hectares of mangrove forests broke the energy of the waves and protected coastal villagers, contributing to a low fatality rate, wetland experts say.
Groups of trees and shrubs that live along shores, rivers and estuaries, mangroves also help capture and store carbon.
But they are increasingly being threatened by human activities.
What are the threats to mangroves?
Mangroves can be found in 118 countries, but 75 per cent of the world’s mangroves are located in just 15 countries in the tropical and subtropical regions, including Indonesia, Brazil and the Philippines, according to data from the Global Forest Watch.
The Global Mangrove Alliance, a network of scientists and conservationists working on mangrove protection, estimates that there are 147,000 square kilometres (56,756 square miles) of mangroves remaining worldwide, which is an area about the size of Bangladesh.
Despite their ecological and economical importance, mangrove forests are declining around the world, with total cover reduced by more than 5,000 square kilometres (1,930 square miles) between 1996 and 2020, according to the Global Mangrove Watch, an online platform that monitors mangroves.
More than half of the world’s mangrove ecosystems are at risk of collapse due to deforestation, development, sea-level rise and severe storms, according to a 2024 assessment by the International Union for Conservation of Nature (IUCN), a global NGO.
Conservationists are calling for a stop to mangrove habitat destruction, with a goal of expanding the global mangrove habitat by 20 per cent by 2030.
Can mangroves protect communities from extreme weather?
Mangroves act as barriers to storms, coastal erosion and flooding.
While mangroves cannot completely block high water levels that are generated during storm surges, they slow down storm speeds, waves and coastal flooding, according to a 2024 study by the Delft University of Technology in the Netherlands.
Mangroves also prevent more than US$65 billion in property damage from storms and reduce flood risk to some 15 million people every year, according to a report published in the Nature journal in 2020.
In the Philippines, where 60 per cent of the population lives along the coast, mangroves are increasingly important in the face of rising sea levels, population growth and urban expansion, according to Wetlands International Philippines, an NGO.
However, the country has lost more than 30 per cent of its 450,000 hectares of mangrove forests over the last century, according to the Philippines’ Climate Change Commission.
According to the IUCN assessment, mangroves protect 15.4 million people and US$65 billion worth of property per year from coastal disasters.
How can mangroves slow climate change?
Mangroves are the most efficient natural carbon capture and storage systems on earth, currently storing carbon that is equivalent to more than 21 billion tons of carbon dioxide, according to a 2021 Global Mangrove Alliance report.
This is equivalent to about half of the total world carbon dioxide emissions in 2022.
Mangrove ecosystems store carbon in their leaves, stems, branches, roots and non-living biomass such as litter and dead wood for hundreds and even thousands of years.
In its 2024 report, the Alliance estimated mangroves hold an average of 394 tonnes of carbon per hectare in their living biomass and in the top meter of soil and more than 650 tonnes per hectare in some places like the Philippines.
However, the conversion of mangroves for aquaculture, palm oil plantations and rice cultivation accounted for 43.3 per cent of global mangrove loss between 2000 and 2020, according to the Alliance.
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