Profiling shipping activities to and from California ports: Greenhouse gas emissions and the technological feasibility of alternative marine fuels

The California Air Resources Board (CARB) regulates emissions from ships operating within state waters but does not cover emissions from voyages to and from California ports that occur outside of regulated areas. By expanding its regulatory scope, CARB could cover up to five times more carbon dioxide equivalent (CO2e) emissions, depending on scope.

Using the ICCT’s SAVE model, this brief finds that ships within California’s regulated waters emitted 2.4 Mt of CO2e in 2022, more than 70% of which was from container ships, oil tankers, and cruise ships. Ships on voyages to and from California ports emitted 13.3 Mt CO2e, most of which occurs outside current regulatory reach. To address this gap, CARB could first consider regulating the greenhouse gas (GHG) intensity of fuels used on voyages starting or ending at California ports.