Indian Ocean, Bay of Bengal potential CO2 sinks: IIT-M researchers

CHENNAI: The Indian Ocean and the Bay of Bengal are potential storage sinks for storing large amounts of carbon dioxide (CO2), said researchers from IIT-Madras.

Called 'CO2 sequestration’, this process envisages the ocean acting like a storage reservoir for greenhouse gas, which will help to decarbonise industrial clusters.

The researchers found that CO2 can be stored permanently in liquid form in the ocean in the form of solid hydrate beyond 500m depth.

"The key findings of this research is that it can help devise large-scale CO2 storage and utilise the fullest potential of oceans to decarbonise the world without harming marine ecology. This research can also help India achieve its national decarbonisation and climate change goals," the institute said in a release.

"The stored carbon dioxide can create an eco-friendly ice-like substance called 'gas hydrates'. One cubic metre of gas hydrate can sequester approximately 150-170 cubic metres of CO2 under oceanic conditions beyond 500 metres. Thus, gas hydrates-based storage has huge potential to decarbonise India's industrial clusters. This research will pave pathways to develop large-scale sequestration in subsea sediments that help the scientific community to fulfil India's net-zero targets," it noted.

"Methane hydrates have been in the ocean for millions of years without affecting the environment. Methane is a more potent greenhouse gas than CO2. This attracts researchers to explore the ocean to store CO2 permanently. Our analysis shows that at above 2,800 m depth, CO2 is denser than seawater, which offers an additional gravitation barrier for CO2 to escape," said professor Jitendra Sangwai, who led the research.

Once the CO2 is permanently stored as a gas hydrates, it does not allow for any reemission into the atmosphere owing to gravitational and hydrate permeability barrier in the subsea sediments.

Noting that the dependence on fossil fuels will continue for the foreseeable future, he added, “Thus, CO2 capture and sequestration is a very important precursor to achieve a net-zero goal.”