The Zero Carbon Act: Approaches to International Shipping Emissions

Published on: July 18, 2017

Filed Under: Analysis, The Zero Carbon Act

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The United Kingdom Climate Change Act is useful starting point for developing the Zero Carbon Act. However, there are flaws in the UK’s approach to international shipping that must be better addressed in New Zealand.


The first issue is the method of calculating what portion of international shipping emissions a country should be responsible for. The goal of the UK legislation is to achieve an 80% reduction in overall emissions by 2050 and this includes their share of international shipping emissions. In advice to the Government, the UK Committee on Climate Change (CCC) evaluated three methods of calculating these emissions.[1]


The original decision of the UK government was for these to be calculated on a bunker-fuel basis, estimated from the amount of fuel sold in the UK. This can be inaccurate, however, as ships tend to stop and refuel at ports along a journey, meaning the full amount of emissions from a journey are not included in the estimation. At the time of the legislation, the CCC considered there was insufficient research to allow more in-depth estimations.


The second method considered, the top down method, calculates each country’s share of international shipping emissions from their shares in global trade (based on shares in cargo, world fleet, income and land-based CO2 emissions).[2] This however, fails to take into account the distance and carbon intensity of the ships’ journeys and is inaccurate where countries have high levels of non-freight shipping e.g. passenger ships and fishing vessels.


The third and most accurate method of calculation is the bottom up method, which considers each ship’s distance travelled, carbon intensity and trade data. This is the method the CCC recommends as the ultimate goal for calculating shares of international shipping emissions.


Though at the time the UK Act came into force there was not enough global information to use the bottom up method, this has been changed recently by the MRV Shipping Regulation. Adopted in 2015, these new regulations require any large ship that docks in European Union ports to be a part of a reporting scheme that monitors its emissions.[3] This is the first step in the European Commission’s strategy to ultimately reducing international shipping emissions.


It is important New Zealand accurately accounts for its share of international shipping emissions as we are an island nation that relies heavily on shipping. It is not unreasonable or unviable to use the bottom up method of calculating New Zealand’s share of emissions given the EU already requires many large ships to keep account of their emissions. Requiring the same level of information in New Zealand would therefore be little extra strain.


In addition to problems with calculating emissions, the UK approach also has another issue that should be avoided in New Zealand. Though their share of international shipping emissions is included in the overall 2050 reductions, the UK Government has consistently elected to omit these emissions from their short-term targets. This is counter to CCC advice in both 2012[4] and 2016[5] that they should be included. The consequence of not including international shipping emissions in periodic targets is that there is less incentive to reduce emissions in the shipping sector and instead the emissions must be made up for with reductions in other sectors.


Thankfully, it is Gen Zero’s intention to include New Zealand’s share of international shipping emissions in the targets set under the Zero Carbon Act.[6] This is important because shipping is such a large area of emissions in New Zealand. It is in our long-term interest to include it in periodic targets, as this will give incentive to the industry to develop technology and operating methods to reduce emissions in the sector, rather than just relying on other areas to cover the emissions.


Though the UK Climate Change Act is a valuable starting place for our own legislation, when it comes to international shipping there are issues with the UK approach. New Zealand has the opportunity to learn from the UK’s shortfalls and make better decisions that will have a more positive impact on our long-term goal of achieving net zero emissions.


Ella Morrison

[1] United Kingdom Committee on Climate Change Scope of carbon budgets: Statutory advice on inclusion of international aviation and shipping April 2012 at 26.

[2] United Kingdom Committee on Climate Change Review of UK Shipping Emissions November 2011 at 18.

[3] “Reducing emissions from the shipping sector” (24 April 2017) European Commission <>.

[4] Above n 2 at 20.

[5] “CCC welcomes Government backing for fifth carbon budget and continued ambition to meet 2050 target” (30 June 2016) Committee on Climate Change <>.

[6] “FAQ: Does the Zero Carbon Act cover international flights?” Zero Carbon Act <>.

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