The global cost of greenhouse gas emissions is nearly double what scientists previously thought, according to a study published Thursday by researchers at the University of California, San Diego’s Scripps Institution of Oceanography.
This research marks the first time a social cost of carbon (SCC) assessment—a critical metric of the economic harm caused by climate change—has considered ocean-related damages. The study estimates that global coral loss, fisheries disruption, and coastal infrastructure destruction could cost nearly $2 trillion annually, significantly altering the framework for measuring climate finance.
“For decades, we’ve been estimating the economic cost of climate change while effectively assigning a value of zero to the ocean,” said Bernardo Bastien-Olvera, who spearheaded the study during his postdoctoral fellowship at Scripps. “Ocean loss is not just an environmental issue, but a central part of the economic story of climate change.”
The social cost of carbon is an accounting method used to determine the monetary cost of each ton of carbon dioxide released into the atmosphere. “It is one of the most efficient tools we have for internalizing climate damages into economic decision-making,” noted Amy Campbell, a United Nations climate advisor and former British government COP negotiator.
These calculations have historically been utilized by international organizations and state departments, including the US Environmental Protection Agency, to evaluate policy proposals. However, a 2025 White House memo from the Trump administration directed federal agencies to omit this data during cost-benefit analyses unless legally obliged.
“It becomes politically contentious when deciding whose damages are counted, which sectors are included, and most importantly, how future and retrospective harms are valued,” Campbell explained.
Excluding ocean harm, the social cost of carbon is $51 per ton of carbon dioxide emitted. This figure increases to $97.20 per ton when considering the ocean, which covers 70 percent of the planet. In 2024, global CO2 emissions were estimated at 41.6 billion tons, making the 91 percent cost increase significant.