‘Climate change weakens oceans' ability to absorb carbon dioxide’

New Delhi: The world's oceans have already lost around six per cent of their capacity to absorb carbon dioxide due to climate change, raising concerns that more greenhouse gases will remain in the atmosphere, the United Nations has warned.

A report titled Climate Technology Progress Report 2026: Navigating Ocean-based Technologies, prepared by the UN Environment Programme (UNEP) in collaboration with the UN Framework Convention on Climate Change (UNFCCC), identifies rising temperatures and changes in ocean chemistry, circulation, and ecosystems as major factors that are weakening the marine carbon sink.

The report warns that the decline could accelerate in the coming years. Limited monitoring data, particularly from the Southern Ocean, Indian Ocean, Arctic and coastal regions, remains a major obstacle. It calls for an integrated monitoring framework, described as Ocean Carbon Intelligence, that combines scientific research, technology, data, and local knowledge.

The assessment identifies ocean observation, blue carbon ecosystems and marine carbon dioxide removal as three priority areas. Mangroves, seagrass meadows and salt marshes currently absorb and store around 407 million tonnes of carbon dioxide annually. Restoring these habitats could strengthen carbon storage while protecting coastlines, biodiversity and livelihoods.

However, technologies designed to remove carbon dioxide directly from the ocean remain experimental and require further research and regulation. The UN cautions against treating them as alternatives to reducing emissions or protecting natural ecosystems.

The report also urges greater financial assistance, technology transfer, and capacity-building for Small Island Developing States, which contribute less than one per cent of global emissions but face severe climate impacts and rising sea levels.