Maritime Area Restoration Evaluation (MARE)
Core Purpose
MARE charges ports for the measurable environmental impact of shipping traffic in defined catchment areas of UK waters. It ensures that those who benefit from maritime trade bear a fair share of the costs of pollution, habitat degradation, and ecosystem stress caused by vessel traffic.
Scope and Measurement
MARE covers:
- Air and water pollution from ships (SOx, NOx, particulates, heavy metals)
- Ballast water discharge and invasive species
- Underwater noise pollution affecting marine mammals
- Physical damage to seabeds from anchoring and dredging
- Contribution to marine litter
Impacts are assessed using a combination of vessel tracking data (AIS), port traffic records, and environmental monitoring within defined maritime zones associated with each major port.
Liability and Charging
Liability is placed on the port operator, who may then pass costs on to shipping lines through fees. Charges are calculated annually based on:
- Volume and type of cargo
- Number and class of vessels
- Environmental performance of the vessels (e.g. scrubbers, fuel type, speed)
Ports that invest in cleaner infrastructure, better waste reception facilities, or incentivise low-impact shipping pay less.
Incentive Effects
MARE encourages:
- Adoption of cleaner marine fuels and technologies
- Investment in shore power (cold ironing)
- Better waste management and recycling at ports
- Routing and speed optimisation to reduce emissions and noise
Interaction with Other PETS Taxes
Revenue from MARE reduces the overall burden on Heat Output Tax (HOT). This maintains the “revenue seesaw” principle across the entire PETS suite — successful reduction of maritime externalities lowers the tax load on land-based activities.
Advantages
- Internalises real costs of international trade on British waters
- Rewards cleaner shipping practices without banning trade
- Uses existing port infrastructure and data systems
- Supports marine environmental restoration while funding core state functions
Governance
Assessments are conducted by an independent environmental accounting body under HMRC oversight. Ports have full access to the data and methodology used for their charges and may appeal with independent surveys or third-party audits.