CHENNAI: The State Environment and Climate Change department has estimated that Tamil Nadu’s coastal ecosystem provides carbon sequestration benefits worth $127.35 million/year. On the other hand, degraded seagrass ecosystems cause an economic loss of $2,481/hectare.
As per a study conducted along with Suganthi Devadason Marine Research Institute in Thoothukudi, the present coastal ecosystems have a carbon stock of about 50,000 Mg C (Megagrams of Carbon/tonnes of carbon).
The study was conducted during February-May 2024 to estimate the blue carbon stocks in the top 1 m of the soil from the 3 ecosystems in TN such as mangroves, salt marsh and seagrass.
For the mangrove ecosystem, the total estimated carbon stock is 5,00,355 Mg C with an economic value of $12.85 million, for the salt marsh ecosystem, it’s 6,63,436 Mg C worth $17.03 million, and for the seagrass ecosystem, it’s 37,97,983.2 Mg C that costs $97.48 million. The report added that seagrass restoration in TN generates an additional 18.69 Mg C/hectare of carbon in the top 1 m soil worth $479.58/ha.
Similarly, it is estimated that the degraded seagrass ecosystem can emit 354.53 t CO2/ha (tonnes of carbon per hectare) if all the carbon in the upper 1m of the soil is oxidised to CO2 (carbon dioxide) with loss estimated at $2,481.71/ha.
The study report recommends wide scale restoration of blue carbon ecosystems using viable protocols, as the degradation and loss have been severe during the past few decades. Provision of proper education and capacity building among the stakeholders, in particular, coastal communities is of great importance for better and sustainable results.
Climate change adaptation and mitigation measures should be developed and continuously implemented to conserve blue carbon ecosystems as the climatic scenario is deteriorating, the report said.