Estimating greenhouse gas emissions from U.S. maritime
How the U.S. Can Reduce Maritime Emissions and Fight Climate Change
The Role of Shipping in the U.S. Economy
Maritime shipping is an essential part of the U.S. economy, adding over $40 billion in value in 2022. This industry moves goods across oceans, connecting the U.S. to the world. However, it also causes environmental harm by burning fuels like heavy oil, marine gas oil, and liquefied natural gas (LNG). These fuels release greenhouse gases (GHGs), which make climate change worse.
Climate change is already causing problems, such as coastal flooding and stronger storms, which led to $165 billion in damages in 2022 alone. To address this, the U.S. has set a goal to reach net-zero GHG emissions from shipping by 2050.
Missing Pieces in Emission Data
The U.S. government currently estimates shipping emissions based on fuel sales, but this method has flaws. It does not account for ships that refuel outside U.S. waters. Another method uses ship tracking data but only measures emissions within U.S. waters.
Because of these gaps, the official U.S. estimate of 32 to 45 million tonnes of carbon dioxide (CO2) emissions is likely too low. This incomplete data makes it hard to understand the true environmental impact of shipping.
The European Union (EU) has a more accurate system called the Monitoring, Reporting, and Verification (MRV) program. It requires ships over 5,000 gross tons to report fuel use and emissions for all trips to, from, and within EU ports. In 2022, this system tracked 137 million tonnes of CO2 emissions.
Why the U.S. Needs an MRV Program
The U.S. already has experience with emission tracking in aviation. The Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) allows airlines to report emissions voluntarily. However, the system only provides general data and does not track individual planes.
A similar program for maritime shipping could collect more detailed data. If the U.S. adopts an MRV system like the EU’s, it could monitor around 11,100 ships, many of which already report to the EU MRV.
Big Benefits of an MRV Program
By adopting an MRV system, the U.S. could improve emissions tracking and create economic opportunities. Better data could show the real scale of emissions—likely closer to 103 million tonnes of CO2 in 2022.
This program could also support carbon pricing, where shipping companies pay fees for their emissions. For example, charging fees for half of international voyage emissions and all domestic and port emissions could bring in $4.5 billion to $15 billion per year.
A Step Toward Climate Goals
An MRV system would help the U.S. achieve its climate goals and reduce the impact of shipping on the environment. With many ships already following EU rules, transitioning to a U.S. MRV program should be relatively easy.
By improving emissions data and introducing carbon pricing, the U.S. can take a big step toward reducing maritime emissions and fighting climate change.
