Climate & resilience
UN warns ocean’s carbon‑absorbing power slipping as climate heats up
A UN report released on Oct. 28 warns that rising ocean temperatures have already reduced the sea’s capacity to absorb carbon dioxide by roughly six percent, a loss that could accelerate climate warming and jeopardize coastal communities that depend on marine resources. The assessment, prepared by UNEP and the UNFCCC, also highlights urgent data gaps in the Southern, Indian and Arctic oceans and calls for expanded monitoring, blue‑carbon restoration and responsible marine carbon‑removal research.
American Impact Alliance News Desk2 minute read
Diminishing carbon sink
The ocean currently absorbs around 30 percent of anthropogenic carbon dioxide and about 90 percent of excess heat trapped by greenhouse gases. The UN Environment Programme and the UN climate secretariat report that climate‑driven warming has already reduced this carbon‑uptake capacity by approximately six percent. Higher temperatures and shifting chemistry, circulation and ecosystems weaken the sea’s ability to store CO₂, leaving more of the gas in the atmosphere. The report warns that this weakening could accelerate, undermining global efforts to limit warming and increasing pressure on communities that rely on marine resources.
Data gaps and technology needs
Because reliable ocean monitoring is scarce in the Southern and Indian Oceans, the Arctic and many coastal zones, the report calls for stronger “ocean carbon intelligence” that blends science, technology, data and local knowledge. The most mature tools are observation systems—sensors, data networks and modelling platforms—that can be deployed immediately to track carbon fluxes. Blue‑carbon habitats such as mangroves, seagrasses and salt‑marshes already sequester about 407 million tonnes of CO₂ each year and also shield shorelines and support biodiversity. Marine carbon‑dioxide removal technologies remain experimental, and the report cautions that they must complement, not replace, emissions cuts and ecosystem protection.
Island nations and blue‑carbon solutions
Small Island Developing States, which together emit less than one percent of global CO₂, are already feeling the front‑line impacts of a weakening ocean sink. The report highlights the need for greater access to finance, technology transfer and capacity‑building so these nations can scale ocean‑based solutions. Seychelles, for example, used a 2015 debt‑for‑nature swap to create a trust fund that finances marine conservation, climate resilience and a sustainable blue economy. In the Pacific, more than 100 people have been trained to assess blue‑carbon stocks in seagrass and mangrove ecosystems, providing data that can be integrated into national climate plans.