By Lucy Caulkett-
A groundbreaking new study has revealed that when damage to the world’s oceans is included in climate change cost estimates, the economic burden of global warming nearly doubles, underscoring the vast and often overlooked financial toll of environmental degradation.
The research conducted by scientists at the Scripps Institution of Oceanography at the University of California San Diego introduces what experts are calling the “blue” social cost of carbon, a metric that incorporates ocean damage alongside traditional climate impact calculations.
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This updated analysis marks the first time that ocean‑related climate losses, including harm to fisheries, coral reefs, coastal infrastructure, and other marine ecosystems, have been systematically factored into estimates of the economic effects of greenhouse gas emissions.
The results suggest that the financial burden of carbon dioxide emissions long understood to contribute to heatwaves, droughts, and storm damages has been significantly underestimated.
Traditionally, climate economists have focused on land‑based impacts of warming such as agricultural losses, health costs, and infrastructure damage when calculating the social cost of carbon. However, this new study shows that excluding the ocean’s role masks a massive chunk of the economic consequences of human‑driven warming.
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While Integrating ocean degradation data, the researchers found that the overall damage from emissions nearly doubles compared to previous figures that ignored marine impacts.
“The ocean has absorbed vast amounts of heat and carbon, but its degradation imposes a very real economic burden that must be accounted for,” said one of the study’s lead authors. Coral reef loss, fisheries decline, and rising sea levels are no longer ecological side effects they are measurable drivers of economic harm that affect jobs, food security, tourism, and coastal protection.
This finding is significant because it challenges long‑standing assumptions in climate economics. Many decades, the ocean’s role as a carbon sink and climate regulator was recognised in the scientific community, but its economic consequences remained undercounted in policy‑relevant cost estimates.
With the addition of ocean‑related damages, the resulting “blue social cost of carbon” offers a more complete picture of how climate change could strain global economies in the decades ahead.
Economists use the social cost of carbon to inform government policy, from setting emissions standards to evaluating the benefits of climate mitigation. A dramatic upward revision, such as this, could significantly influence how policymakers weigh climate action potentially reinforcing the economic case for more aggressive emissions reductions worldwide.
Crucially, the ocean’s contribution to climate regulation makes its degradation doubly impactful: as the ocean warms, it absorbs more heat over 90% of the excess heat from greenhouse emissions which spurs harmful changes like sea‑level rise and more powerful storms. That warming also stresses marine ecosystems, affecting biodiversity, fish stocks, and coastal resilience.
The study’s inclusion of ocean costs comes amid mounting evidence that climate change already imposes enormous economic strains on societies around the world. Oceans are central to the global economy, supporting fisheries, tourism, trade, and coastal protection, while also stabilising climate systems that underpin agriculture and human health.
According to United Nations research, seas have absorbed about 90% of the excess heat from human‑generated emissions, driving cascading changes that affect billions of people through hotter waters, higher seas, and disrupted weather patterns.
Moreover, recent climate data show that the ocean’s heat content has been rising to record levels, contributing to extreme weather events and worsening already costly climate disasters. In 2025, the ocean absorbed an unprecedented amount of heat estimated at 23 zettajoules more than the previous year reinforcing its central role in climate dynamics.
When ocean damage is factored into economic models, the implications are profound. Losses linked to marine ecosystem decline such as reduced fishery yields, coral bleaching, coastal flooding, and infrastructure damage represent direct costs to local and global economies. While island nations and coastal regions reliant on marine resources, these costs are existential as well as financial.
This expanded lens on climate economics aligns with broader research showing that climate change is already reshaping global financial stability. A 2024 study estimated that the world economy is on track to suffer annual losses in the tens of trillions of dollars if warming continues unabated, affecting productivity, infrastructure, and human wellbeing.
Understanding the economic fallout of rising seas and warming oceans has direct policy implications. Governments use cost estimates like the social cost of carbon to set carbon pricing, design adaptation strategies, and justify investments in green technology.
Nearly doubling the estimated cost of carbon emissions, this new analysis shifts the calculus on how urgently countries should pursue emissions reductions and climate resilience planning.
Environmental advocates argue that the updated figures strengthen the case for transforming energy systems, investing in coastal protections, and preserving ocean health as part of climate mitigation.
“If we don’t put a price tag on the harm that climate change causes to the ocean, it will be invisible to key decision makers,” said environmental economist Bernardo Bastien‑Olvera, who helped lead the study, highlighting how ocean impacts have been overlooked in past estimates of climate costs.
At the same time, critics note that integrating new categories of damage into economic models introduces complexity; social cost estimates can vary widely depending on assumptions about future emissions, adaptation efforts, and technological advancements.
Still, the central message is gaining traction: the ocean’s economic losses matter, and they are larger than previously recognized. From shrinking fish stocks that support millions of jobs to eroding coastlines that threaten property and infrastructure, the ripple effects of a warming ocean could shape economic prospects for decades.
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