IUCN lists Tamil Nadu mangroves 'critically endangered'

CHENNAI: Mangroves along the South India Coasts, especially the east coast covering Tamil Nadu, are critically endangered, according to The International Union for Conservation of Nature (IUCN) organisation's first global mangrove assessment.

The assessment was done under the Red List of Ecosystems initiative that aims to evaluate ecosystem risks.

According to the study, the mangrove ecosystems are spread across 36 regions in 44 countries with critically endangered ecosystems in South India, Sri Lanka, Maldives, and the North Atlantic (part of North America).

On the other hand, West India (covering the west coast) and Pakistan region have been categorised as vulnerable and the Bay of Bengal region, which comprises West Bengal and Bangladesh, has been categorised as least concern.

Citing sea-level rise as a major cause of depletion of the mangrove ecosystem, IUCN said that 25 per cent of the world's total mangrove areas could be submerged in the next 50 years and one-third of mangrove regions will be severely affected by sea-level rise. The global mangrove cover is 1,50,000 sq km, noted the study.

However, the impact of sea-level rise on mangrove ecosystems will differ regionally and the Northwest Atlantic, North Indian Ocean, Red Sea, South China Sea, and Gulf of Aden coasts are likely to be severely affected, the assessment added.

The finding warned that without significant measures, climate change and sea level rise will result in the loss of 1.8 billion tonnes of carbon stored (mangroves store 17 per cent of the total current carbon) by 2050, currently valued at a minimum of 13 billion $ at market prices in voluntary carbon markets and representing a cost to society equal to 336 billion $ based on the social cost of carbon.

The protection rendered by the mangroves to 2.1 million lives and 36 billion $ worth of property from the coastal flooding will be at stake. It would also affect the 17 million days of fishing effort per year as 14 per cent of current fishing is mangrove-assisted.

This global assessment shows that more than 50 per cent of mangrove ecosystems are at risk of collapse. About 7,065 sq km of mangrove cover will be depleted and 23,672 sq km will be submerged by 2050 in case of the absence of additional conservation efforts, predicted IUCN.

Observing that there is an expansion of mangrove patches into temperate areas, such as in parts of the Pacific, where they were not previously present, the IUCN said,

Conversely, climate change and widespread freshwater diversion for agricultural irrigation leading to freshwater scarcity and adequate sediment supply enhance the mangrove growth.

The EnviStats India 2022 released by the Ministry of Statistics and Programme Implementation estimated the total mangrove cover at 45 sq km in 2021. The report said that the total mangrove cover has increased from 23 sq km in 1987 to 45 sq km.

The Tamil Nadu districts such as Thoothukudi, Pudukottai, Tiruvallur, and Tiruvarur did not have any mangrove cover in 2001. But in 2021, these districts were found to have a considerable extent of mangrove forest with Tiruvarur having mangrove cover at 13 sq km.