Greenhouse gas emissions from the international maritime transport of New Zealandʹs imports and exports

Greenhouse gas emissions from international maritime transport are exempt from liabilities under the Kyoto Protocol. Research into quantifying these emissions is ongoing, and influences policy proposals to reduce emissions. This paper presents a cargo-based analysis of fuel consumption and greenhouse gas emissions from New Zealandʹs international maritime transport of goods. Maritime transport moves 99.5% (by mass) of New Zealandʹs internationally traded products. It is estimated that 73% of visiting vesselsʹ activity can be directly attributed to the movement of goods in and out of New Zealand. A cargo-based methodology was used to estimate that the international maritime transport of New Zealandʹs imports and exports consumed 2.5 million tonnes (Mt; 2.6 billion litres) of fuel during the year 2007, which generated 7.7 Mt of carbon dioxide (CO2) emissions. Double-counting of emissions would occur if a similar method was applied to all New Zealandʹs trading partners. In contrast, since few large vessels refuel in New Zealand, the National Greenhouse Gas Inventory listed 2007 international maritime transportation emissions as 0.98 Mt of CO2, calculated from fuel bunkered for international transport. The results, therefore, show a significant difference between activity-based and bunker-fuel methodologies in quantifying New Zealandʹs emissions. International policy implications are discussed.