In a groundbreaking advancement for climate economics, recent research reveals that the social cost of carbon (SCC)—a critical metric guiding global climate policy—has been drastically underestimated due to the exclusion of ocean-based impacts. Integrating state-of-the-art marine science into an advanced climate-economy model, scientists have captured how climate change detrimentally affects oceanic ‘blue capital’—the combined value of marine ecosystems and infrastructure that underpin global well-being and economies. The findings show that once this overlooked ocean component is accounted for, the estimated SCC nearly doubles, indicating far greater economic damage from carbon emissions than previously acknowledged.
The ocean is foundational to human societies worldwide. Its vast ecosystems—from coral reefs to mangrove forests—and essential infrastructures like seaports make up what is termed ‘blue capital.’ This natural and built marine wealth supports food security, livelihoods, tourism, and global trade, creating immense economic and social value. Yet, climate change poses existential risks to these assets through ocean warming, acidification, sea-level rise, and extreme weather, leading to widespread degradation. Until now, these ocean-related damages have been largely absent in popular climate cost assessments, creating a critical blind spot in understanding the true costs of carbon emissions.
To close this gap, a consortium of environmental economists and marine scientists developed a novel integrated assessment model, enriching traditional approaches by embedding rigorous marine impact science. Their framework specifically quantifies the climate-induced degradation of multiple ocean systems—coral reefs suffering bleaching events, collapsing mangrove forests, deteriorating seaport infrastructure threatened by sea-level rise and storms, alongside shrinking fisheries and mariculture yields curtailed by shifting ocean conditions. This comprehensive synthesis links ecological changes with economic consequences that ripple through global welfare.
The model’s outputs deliver a startling conclusion: the ocean’s climate-related costs add approximately US$48 per ton of carbon dioxide emitted as of 2020, with a bootstrapped confidence interval ranging from US$38 to US$70. This ocean-inclusive figure nearly doubles the SCC value derived from models excluding marine impacts, signaling substantial hidden costs. When the analysis applies a more conservative discount rate of 2%—reflecting increased emphasis on future generations’ welfare—the blue SCC skyrockets to US$168 per ton of CO2, suggesting oceans greatly amplify carbon’s economic externality.
Understanding this augmented social cost of carbon has profound implications for policymaking. Current carbon pricing mechanisms, climate damage assessments, and emission reduction targets are based on SCC values that may substantially undervalue the benefits of aggressive climate mitigation. Incorporating ocean-driven damages into these calculations provides governments and international bodies empirical evidence underscoring the imperative for more ambitious climate action, aligning economic signals with the true scale of environmental risks.
The scientific rigor and interdisciplinary approach of the research stand out as hallmarks of its credibility. By leveraging the most up-to-date oceanographic data and employing cutting-edge ecological-economic modeling, the research team precisely maps ocean climate vulnerability onto global welfare metrics. This integration moves beyond simplistic or static methodologies, capturing dynamic feedbacks and regional heterogeneities that more accurately reflect real-world conditions and economic dependencies on the marine environment.
Coral reefs represent one of the most visibly impacted ecosystems. Climate-driven warming causes recurrent coral bleaching, reducing reef structural complexity and undermining biodiversity hotspots. This degradation translates into diminished fisheries productivity and tourism revenue, livelihoods loss, and erosion of shoreline protection services. The model quantifies these adverse outcomes, attributing significant economic damages to coral decline that were previously missing from standard SCC estimates.
Likewise, mangrove ecosystems, vital carbon sinks and protective coastal buffers, are imperiled by rising temperatures, altered precipitation regimes, and intensified storm activity. Their loss accelerates carbon emissions stored in blue carbon reservoirs and exposes coastal communities to flooding and erosion. Inclusion of mangrove degradation magnifies the overall social cost of carbon by capturing these cascading ecosystem service failures, further contributing to the sharply elevated ocean-inclusive SCC values.
Critical infrastructure, such as seaports, faces increasing vulnerability from sea-level rise and extreme weather events associated with climate change. Damage to these nodes disrupts global supply chains and trade flows, generating large-scale economic reverberations. Modeling these infrastructure impacts within the SCC framework reveals significant additional costs that accentuate the economic stakes of unabated carbon emissions and the importance of resilience investments.
Fisheries and mariculture are two major ocean-dependent economic sectors that climate change threatens through alterations in ocean temperature, chemistry, and circulation patterns. These shifts affect fish stock distributions, productivity, and the viability of aquaculture operations. By embedding fisheries and mariculture losses into the social cost of carbon, the assessment integrates vital food security and economic risks hitherto underestimated in climate policy debates.
The enhanced understanding provided by this holistic ocean-inclusive SCC approach marks a paradigm shift in climate economics. It underscores the interconnectedness of marine health and human welfare, emphasizing how environmental degradation in oceans exacerbates the broader societal costs of carbon emissions. This research lays the groundwork for integrating ocean-centric perspectives into global carbon pricing frameworks, potentially influencing climate negotiations, carbon markets, and funding priorities.
Moreover, the findings encourage cross-sector cooperation, bridging ocean science, environmental economics, and policy design. By articulating the economic ramifications of ocean ecosystem loss and infrastructure damage, the analysis empowers stakeholders to advocate for integrated conservation and adaptation strategies. These encompass emission reductions, marine protected areas, coastal defenses, and sustainable fisheries management—all essential components for minimizing the elevated blue social cost of carbon.
The profound increase in the social cost of carbon due to ocean impacts also brings ethical considerations to the fore. It highlights how vulnerable communities, especially those reliant on marine resources, may bear disproportionate burdens from climate change. The elevated blue SCC therefore strengthens the argument for climate justice and the need for targeted support mechanisms within global climate frameworks.
Importantly, this research opens avenues for future exploration. As ocean science advances and modeling techniques refine, even greater resolution and accuracy can be realized, encompassing additional blue capital components such as deep-sea ecosystems, offshore renewable infrastructure, and ocean-based carbon sequestration technologies. Such inclusions could further recalibrate social cost estimates and inform adaptive governance in marine contexts.
In summary, accounting for ocean impacts reveals that our previous understanding of carbon’s social cost was severely incomplete. By nearly doubling the social cost of carbon, this pioneering work exposes the monumental economic risks tied to ocean degradation and redefines the stakes for climate mitigation policies. The ocean, often labeled the planet’s life support system, must be central in climate-economic assessments to ensure comprehensive, just, and effective solutions to the global climate crisis.
This transformative integration of marine science into climate economics robustly demonstrates that protecting ocean health is not only an environmental imperative but an economic necessity. Policymakers, economists, and environmentalists alike must now confront this amplified social cost of carbon, shaping climate strategies that truly reflect the interconnected nature of Earth’s systems and human prosperity.
Subject of Research: Climate-economy modeling integrating ocean ecosystem and infrastructure impacts on the social cost of carbon.
Article Title: Accounting for ocean impacts nearly doubles the social cost of carbon.
Article References:
Bastien-Olvera, B.A., Aburto-Oropeza, O., Brander, L.M. et al. Accounting for ocean impacts nearly doubles the social cost of carbon. Nat. Clim. Chang. (2026). https://doi.org/10.1038/s41558-025-02533-5
Image Credits: AI Generated
