The true cost of climate change is far higher than previously estimated, with new research showing that damage to oceans almost doubles the global economic burden of greenhouse gas emissions. A landmark study by scientists at the University of California San Diego Scripps Institution of Oceanography has, for the first time, included ocean-related losses in calculating the social cost of carbon, fundamentally reshaping how climate damage is valued worldwide.
The study estimates that ocean degradation caused by climate change, including coral reef loss, disruption of fisheries and damage to coastal infrastructure, results in nearly two trillion dollars in losses every year. Until now, most economic models assessing climate impacts had effectively assigned zero value to oceans, despite them covering about 70 percent of the planet.
On How Ignoring the Oceans Has Undervalued Climate Damage
The social cost of carbon is a critical economic tool used to estimate the monetary harm caused by each tonne of carbon dioxide emitted into the atmosphere. It guides climate policy decisions, investment strategies and regulatory frameworks across governments and international institutions. Traditionally, this figure stood at around 51 dollars per tonne of carbon dioxide. However, when ocean-related damages are included, the cost rises sharply to 97.20 dollars per tonne, an increase of nearly 91 percent.
Lead researcher Bernardo Bastien-Olvera said the omission of ocean damage has long distorted climate economics. He explained that for decades, climate models treated ocean loss as if it had no economic value, despite oceans supporting food systems, trade routes, coastal protection and livelihoods for millions. The revised estimates reflect not only direct market losses, such as reduced fisheries and damaged ports, but also broader impacts on tourism and marine-based recreation.
In 2024 alone, global carbon dioxide emissions reached an estimated 41.6 billion tonnes, making the revised cost assessment highly significant. The study projects that by 2100, annual damages to traditional markets could reach 1.66 trillion dollars, even without accounting for many indirect and long-term impacts.
Onwards to Rethinking Climate Finance and Global Responsibility
Beyond market losses, the researchers also placed monetary value on what economists describe as non-use values. These include the cultural, ecological and emotional importance of marine ecosystems, even for people who may never directly experience them. From coral reef spawning events to deep-sea biodiversity, these elements contribute to the planet’s livability and collective human heritage.
The study highlights that island nations and low-income coastal countries will suffer the most severe consequences. These regions depend heavily on seafood for nutrition and livelihoods, making them particularly vulnerable to ocean warming and acidification. Crucially, the countries most responsible for climate change are often not the ones facing the earliest or harshest damages, deepening global inequality.
Co-author Kate Ricke of UC San Diego noted that including ocean damage in climate cost calculations exposes serious risks to public health, nutrition and mortality in vulnerable nations. She expressed hope that recognising the high “blue social cost of carbon” would drive stronger investments in ocean adaptation, including coral reef restoration, mangrove protection and coastal resilience.
Researchers believe the findings could mark a turning point in international climate decision-making. By placing oceans at the centre of climate economics, the study acknowledges the long-standing knowledge of coastal communities, ocean scientists and Indigenous peoples who have long warned that ocean health is inseparable from planetary stability.
The inclusion of ocean damage, the authors argue, is not just a technical correction but a moral and economic reckoning. It challenges policymakers to rethink climate finance, responsibility and action, and to finally recognise that the oceans are not priceless because they are free, but because their loss carries an enormous cost for humanity and the future of the planet.