Ocean damage nearly doubles economic cost of climate change

Scripps researchers report that adding ocean impacts to the social cost of carbon raises the global cost by about $46.2 per ton, nearly doubling it to $97.2 per ton and implying roughly $2 trillion in annual ocean-related damages based on 2024 emissions estimates.

Researchers at the Scripps Institution of Oceanography have included ocean impacts in the social cost of carbon for the first time and found the change substantially increases estimated economic harms from emissions. The team reports that ocean damages add about $46.2 per ton of CO2, raising the social cost to $97.2 per ton, a 91% increase. The study, published in Nature Climate Change, uses integrated assessment models and considers market and non-market losses tied to reefs, fisheries, mangroves and coastal infrastructure. The authors note that impacts are unevenly distributed and that islands and small economies may be especially affected. Main findings: - Ocean-related damages add approximately $46.2 per ton of CO2, bringing the social cost to $97.2 per ton, a reported 91% increase over standard estimates. - Using a 2024 emissions figure of 41.6 billion tons, the paper implies nearly $2 trillion in annual ocean-related damages that are not usually included in standard cost estimates. - The study cites harms to coral reefs, fisheries, mangroves and coastal infrastructure and reports that the distribution of impacts is highly unequal, with small island and coastal economies particularly vulnerable. Summary: Including ocean harms nearly doubles the estimated social cost of carbon and increases the scale of economic damages attributed to greenhouse gas emissions. Undetermined at this time.