Climate Central Solutions Brief: Ocean Carbon

The document describes the ocean as the planet's largest carbon sink, sequestering approximately 26% of human-released CO2 annually. It details the biological and physical carbon pumps, the role of large marine mammals and coastal ecosystems in 'blue carbon' storage, and evaluates emerging geoengineering approaches for carbon dioxide removal (CDR). The brief emphasizes that while ocean-based solutions build resilience and biodiversity, they must be paired with rapid emissions cuts to effectively slow global warming.

• Oceans act as the largest carbon sink on Earth, storing approximately 45 times more carbon than the atmosphere and 12 times more than terrestrial ecosystems, with roughly 26% of annual human-caused CO2 emissions being sequestered by the ocean.
• Human-induced climate change is disrupting the ocean carbon cycle; since the Industrial Revolution, the absorption of CO2 has increased ocean acidity by about 30%, and the ocean has absorbed 90% of the excess heat caused by carbon pollution.
• The 'biological carbon pump' moves carbon to the deep ocean through sinking biomass and the 'diel vertical migration' of organisms in the twilight zone, the latter of which may contribute about 16% of the total annual carbon transfer to the deep sea.
• Restoring whale populations offers significant carbon storage potential; for example, returning blue whales to pre-whaling levels could result in 200,000 tons of annual carbon storage, as large marine animals move carbon to the seafloor upon death.
• Coastal 'blue carbon' ecosystems, such as seagrass meadows, are critical but threatened; seagrasses hold about 11% of buried blue carbon, yet at least 7% of these ecosystems are lost annually to degradation or development.
• Several emerging geoengineering approaches for carbon dioxide removal (CDR) are being researched, though they face significant challenges: alkalinity enhancement could potentially sequester over 1 GtCO2 annually, while electrochemical methods would require energy equivalent to 20% of the projected global electricity supply increase by 2040 to remove 1 GtCO2 per year.

APA

Climate Central (2023). Climate Central Solutions Brief: Ocean Carbon. https://assets.ctfassets.net/cxgxgstp8r5d/3465fSdvs1ZN9LYy0ALbAA/eb75e3b5b7bed2431f79cde3db96c6c2/FINAL_Oceans_Report_2023__EN_.pdf

Chicago

Climate Central. Climate Central Solutions Brief: Ocean Carbon. 2023. https://assets.ctfassets.net/cxgxgstp8r5d/3465fSdvs1ZN9LYy0ALbAA/eb75e3b5b7bed2431f79cde3db96c6c2/FINAL_Oceans_Report_2023__EN_.pdf.

Wikipedia

{{cite report |author=Climate Central |title=Climate Central Solutions Brief: Ocean Carbon |date=June 2023 |url=https://assets.ctfassets.net/cxgxgstp8r5d/3465fSdvs1ZN9LYy0ALbAA/eb75e3b5b7bed2431f79cde3db96c6c2/FINAL_Oceans_Report_2023__EN_.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{climatecentral2023climate, author = {{Climate Central}}, title = {{Climate Central Solutions Brief: Ocean Carbon}}, institution = {Climate Central}, year = {2023}, month = jun, url = {https://assets.ctfassets.net/cxgxgstp8r5d/3465fSdvs1ZN9LYy0ALbAA/eb75e3b5b7bed2431f79cde3db96c6c2/FINAL_Oceans_Report_2023__EN_.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }