A new report on the state of the mangrove ecosystems warns that the ones in south India are under high risk of collapse due to pollution, deforestation and developmental activities at the coast. They are also vulnerable to sea level rise and the increased frequency of severe storms associated with climate change. However, mangrove ecosystems in western and eastern India are less susceptible to risk.

Mangroves are tropical trees or shrubs that grow in coastal saline or brackish water where other species cannot survive. They act as a natural barrier to coastal soil erosion and other natural disasters like floods. The report, Red List of Mangrove Ecosystems, is the first global mangrove assessment for the International Union for Conservation of Nature (IUCN). It warns that half of the world’s mangrove ecosystems run the risk of collapse.

Indian mangrove ecosystems have been bunched into three parts. The ecosystems in the Bay of Bengal region shared by India and Bangladesh and those in the west shared by India and Pakistan are in the least concerned category. However, the mangrove ecosystem in the south, which India shares with Sri Lanka and Maldives, is categorised as critically endangered.

Mangroves are essential for coastal disaster risk reduction, carbon sequestration and ecological support for fisheries and biodiversity. The report examined the world’s mangrove ecosystems in 36 different regions, prepared with active involvement of more than 250 experts in 44 countries from various research institutions, including the IUCN Species Survival Commission and the Global Mangrove Alliance.

“Mangrove loss stands to be disastrous for nature and people across the globe,” said Angela Andrade, Chair of IUCN Commission on Ecosystem Management. She said the report is key to tracking progress towards the goal of halting and reversing biodiversity loss, in line with the Kunming-Montreal Global Biodiversity Framework. “The Report provides clear pathways on how we can reverse mangroves loss and protect these delicate ecosystems for the future, helping in turn to safeguard biodiversity, tackle the effects of climate change and support the realisation of the Global Biodiversity Framework,” Andrade added.

Wake-up call

Released on the International Day for Biodiversity, the report shows that 50% of the mangrove ecosystems assessed are at risk of collapse – classed as either vulnerable, endangered, or critically endangered. According to the assessment, nearly 20% (19.6%) of the assessed mangroves are at high risk, classed as either endangered or critically endangered, indicating these areas are at severe risk of collapse. It places the world’s top two mangrove ecosystems – ‘Warm Temp North West Atlantic’ and ‘South India and Sri Lanka, and Maldives’ – in the critically endangered category followed by five regions in the endangered and 10 in the vulnerable categories.

Mangroves store almost 11 billion tons of carbon, which is almost three times the amount of carbon stored by tropical forests of the same size. Besides, mangroves protect 15.4 million people and $65 billion worth of property per year from coastal disasters. The protected property cost would rise to $118 billion as population further increases by 2050, the assessment added. Moreover, mangroves support 126 million fishing days per year along with providing valuable employment through millions of fisheries-related jobs. The assessment underlined the urgency to take up additional mitigation measures to protect and reduce risks related to mangrove ecosystems. Healthy mangroves are able to better cope with sea level rise and offer inland protection from the impacts of hurricanes, typhoons and cyclones.

In the absence of additional conservation efforts, by 2050 about ~7,065 km2 (-5%) more mangroves will be lost and ~23,672 km2 (-16%) will be submerged, the report warned. Should the mangroves get further degraded, the report estimates the amount of carbon – the most potent gas that is changing Earth’s climate – that would be released into the atmosphere costing hundreds of billions of dollars in value to society and evolving carbon markets, over millions lives exposed to coastal flooding and damage to billions of dollars worth of properties and loss of millions of days of fishing effort per year. (See box)

“The report gives key guidance that highlights the urgent need for coordinated conservation of mangroves – crucial habitats for millions in vulnerable communities worldwide. The assessment’s findings will help us work together to restore the mangrove forests that we have lost and protect the ones we still have,” said Dr Grethel Aguilar, IUCN Director General.

By 2050 if 5% more mangroves are lost and 16% mangroves get submerged due to lack on conservation, the world would be at risk of losing:

  • 1.8 bn Tonnes of carbon stored, which is currently valued at least at $13 billion at market prices in voluntary carbon markets, represents a cost to society equal to $336 billion based on the social cost of carbon.
  • 2.1 bn Protection for 2.1 million lives exposed to coastal flooding (14.5% of current lives exposed) and $36 billion worth in protection value to properties (35.7% of current property values protected).
  • 17 mn days of fishing effort per year (14% of current fishing effort supported by mangroves).