Ports’ Hidden Carbon Bill: New Model Maps the Road to Maritime Neutrality

When people picture the climate footprint of global trade, they usually imagine container ships burning heavy fuel oil or the smoky diesel engines of yard cranes. A new study argues that this picture misses one of the most stubborn sources of maritime emissions: the concrete and steel that ports are literally made of. In research published in Clean Technologies and Environmental Policy, a team led by Daibing Hou of CCCC Water Transportation Consultants and Beijing University of Chemical Technology presents an integrated framework that combines process-based life cycle assessment with system dynamics modeling to chart realistic pathways toward carbon neutrality for port infrastructure.

The problem the researchers set out to solve is a familiar one in climate accounting. Life cycle assessment, or LCA, is the standard tool for tallying the emissions embodied in a piece of infrastructure, from raw material extraction through manufacturing, construction, and eventual disposal. But conventional LCA is essentially static: it produces a snapshot of a single project at a single point in time. It cannot capture how infrastructure investment decisions, technological progress, and policy interventions interact over decades, nor how those interactions determine whether a sector locks itself into decades of avoidable emissions. Ports are particularly vulnerable to this carbon lock-in, because wharves and terminals built today will still be standing and operating long after mid-century climate deadlines have come and gone.

To bridge that gap, the team coupled the two approaches in what they call an LCA–SD framework. At the project level, they applied process-based life cycle assessment to real engineering schemes, drawing on a dataset of 214 construction designs from 39 Chinese coastal ports. The project-level results were then used to parameterize a national-scale system dynamics model of the port construction sector. System dynamics, a modeling technique that represents stocks, flows, and feedback loops, allowed the researchers to simulate how annual investment volumes, material emission factors, and policy stringency evolve together over time and shape long-term emission trajectories. Scenario and sensitivity analyses were then used to probe how the modeled emissions respond when key assumptions are varied.

The static findings are striking. Across the 214 engineering schemes, material manufacturing accounted for between 79.0 and 91.5 percent of total construction-stage carbon emissions. In other words, the vast majority of a port’s embodied carbon is released before a single pile is driven, in the kilns and blast furnaces that produce cement and steel. These two materials emerged as the dominant emission hotspots, and their relative importance depends on the structural type of the wharf. Piled wharves, which rest on driven or bored piles, are relatively steel-intensive, whereas gravity wharves, which rely on their own massive weight for stability, lean heavily on cement-based materials. That distinction matters for designers, because it means the decarbonization lever differs by structure: steel innovation for one class of wharf, low-carbon cement and concrete for another.

The dynamic modeling then translated these project-level insights into sector-wide trajectories. Under the baseline scenario, in which current trends in investment and technology continue without major policy acceleration, the study projects that sector-wide emissions from port infrastructure construction will peak between 2026 and 2028. That peak is not the finish line. What happens after the peak depends on how quickly low-carbon materials penetrate the market and how aggressively construction volumes are managed. The model shows that stronger intervention could pull the date of carbon neutrality forward by approximately 15 years, a dramatic shift for a sector whose assets are typically designed for lifespans of half a century or more.

Perhaps the most policy-relevant result comes from the sensitivity analysis. Within the tested range of plus or minus 10 percent, the annual emission trajectories proved more responsive to changes in investment volume than to changes in policy intensity. This is a counterintuitive finding with real-world implications. It suggests that the sheer scale of port construction activity, driven by demand for expanded capacity and new terminals, exerts a stronger pull on near-term emissions than the stringency of climate policies applied to each project. A modest swing in how much port infrastructure gets built moves the emissions needle more than a comparable tightening of per-project carbon rules. For planners, this means that managing the pace and volume of infrastructure expansion is not an optional complement to decarbonization policy; it is a central pillar of it.

The authors are careful to frame these results as requiring coordinated action rather than any single silver bullet. Their conclusions point to a portfolio of measures: accelerated deployment of low-carbon materials to attack the cement and steel hotspots, green procurement standards that reward suppliers with lower embodied carbon, design-stage carbon control that makes emissions a criterion when choosing between structural alternatives, and carbon offset mechanisms to neutralize the residual emissions that no material substitution can eliminate. Each of these levers addresses a different stage of the construction life cycle, and the modeling suggests they work best in combination.

The study’s empirical foundation gives it unusual weight. The 214 engineering schemes span a wide range of Chinese coastal port projects, and the carbon accounting draws on established national standards, including the Ministry of Transport’s quotas for maritime works and water transportation budgeting, the construction carbon emission calculation standards issued by China’s housing ministry, and the Chinese life cycle database maintained by IKE Environmental Technology. Emission factors for electricity were aligned with regional grid baselines published by China’s climate strategy authorities and with United Nations Framework Convention on Climate Change methodologies. This grounding in official quotas and databases means the results are not hypothetical modeling exercises but reflect the actual material intensities and construction practices of one of the world’s largest port-building programs.

The broader context makes the findings urgent. Global maritime trade continues to grow, and ports everywhere are expanding to accommodate larger vessels, automated terminals, and new energy supply chains. Every new berth adds tons of embodied carbon that cannot be recalled once the concrete is poured. The concept of carbon lock-in captures this inertia: infrastructure decisions made in the 2020s shape the emissions profile of the 2060s. By quantifying how much of a port’s construction carbon comes from materials, and by showing how investment volume and policy intensity interact dynamically, the study gives port authorities and regulators a quantitative basis for sequencing their decisions. Building less, building smarter, and building with cleaner materials are not competing strategies but complementary ones.

For the international audience watching China’s port sector, the framework itself may be as valuable as the specific numbers. The LCA–SD integration is transferable to other countries and other infrastructure classes, from highways to tunnels, wherever static carbon accounting has struggled to capture the dynamics of long-lived assets. As governments worldwide grapple with how to reconcile infrastructure ambitions with net-zero commitments, this study offers a template: measure the embodied carbon of real projects, feed those measurements into a dynamic sector model, and test how investment and policy levers shift the trajectory. The path to carbon-neutral ports, it turns out, is written in cement and steel, and the sooner planners read it, the more of the future they can still change.

Subject of Research: Integrated life cycle assessment and system dynamics modeling of carbon emissions from port infrastructure construction

Article Title: Decarbonizing port infrastructure: an integrated life cycle assessment–system dynamics framework for carbon neutrality pathways

Article References: Hou, D., Su, D., Shen, W., Zhao, A., Li, X., Meng, X., Ma, J., Pan, J., & Lin, A. (2026). Decarbonizing port infrastructure: an integrated life cycle assessment–system dynamics framework for carbon neutrality pathways. Clean Technologies and Environmental Policy, 28(11), Article 275. https://doi.org/10.1007/s10098-026-03610-9

Image Credits: AI Generated

DOI: 10.1007/s10098-026-03610-9

Keywords: port infrastructure, life cycle assessment, system dynamics, carbon neutrality, embodied carbon, cement, steel, carbon lock-in, green procurement, maritime transport, decarbonization, China