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The primary global framework regulating Greenhouse Gas emissions from international shipping is established by the International Maritime Organization (IMO) under MARPOL Annex VI, updated at MEPC 80 (July 2023).
IMO 2023 Revised GHG Strategy Targets
IMO DECARBONIZATION TRAJECTORY (MEPC 80)
2008 Baseline
│
├--──► 2030: At least 40% reduction in Carbon Intensity (CO₂ / ton-mile)
│ │──► Checkpoint: 20% to 30% total GHG reduction
│ └──► Fuel Uptake: 5% to 10% Zero/Near-Zero GHG fuels
│
├──► 2040: Checkpoint: 70% to 80% total GHG reduction
│
└──► 2050: Net-Zero GHG Emissions from international shipping
Levels of Ambition
- Net-Zero Target: Reach net-zero GHG emissions from international shipping by or around 2050 (taking into account different national circumstances).
- Zero / Near-Zero Fuel Adoption: Uptake of zero or near-zero GHG emission technologies, fuels, and/or energy sources to represent at least 5% (striving for 10%) of energy used by international shipping by 2030.
- Carbon Intensity Reduction: Reduce CO2 emissions per transport work (carbon intensity) as an average across international shipping by at least 40% by 2030 compared to 2008.
Indicative Checkpoints
- 2030 Checkpoint: Reduce annual total GHG emissions from international shipping by at least 20% (striving for 30%) compared to 2008.
- 2040 Checkpoint: Reduce annual total GHG emissions from international shipping by at least 70% (striving for 80%) compared to 2008.
Implementation Framework & Regulatory Instruments
Instrument | Type | Application | Objective |
|---|---|---|---|
EEDI (Energy Efficiency Design Index) | Technical (Design) | Newbuild ships | Mandates progressive reduction factors for ship design efficiency across Phases 0, 1, 2, and 3. |
EEXI (Energy Efficiency Existing Ship Index) | Technical (Existing) | Existing fleet (>400 GT) | One-time certification requiring existing ships to achieve a technical efficiency level comparable to EEDI Phase 2/3. |
CII (Carbon Intensity Indicator) | Operational | Ships ≥ 5,000 GT | Operational carbon intensity calculated annually, assigning an operational rating from A to E. |
SEEMP (Ship Energy Efficiency Management Plan) | Operational / Managerial | All operational ships | Part III requires a mandatory plan to achieve target CII ratings for ships rated D (for 3 consecutive years) or E. |
IMO DCS (Data Collection System) | Reporting | Ships ≥5,000 GT | Mandatory reporting of annual fuel oil consumption and transport work data. |
Candidate Mid-Term Measures (Basket of Measures)
The IMO is developing a two-part measure:
- Technical Element: A goal-based Marine Fuel Standard regulating a phased reduction in the Well-to-Wake (WtW) GHG intensity of marine fuels.
- Economic Element: A global maritime carbon pricing mechanism (e.g., a levy or contribution per tonne of CO2-equivalent emitted) to incentivize clean fuel transition and support developing nations.