To stay below 1.5 degrees Celsius – the goal of the Paris climate agreement – there is an immediate need to reduce carbon emissions. One of the worst-hit sectors is international shipping, with emissions equivalent to those of an industrialized country like Germany. The International Maritime Organization (IMO), the UN’s shipping regulator, has put issues around shipping and climate change on its agenda.
Shipping emissions can be calculated using four main factors: the weight of products transported, the distance they are shipped, the amount of fuel it takes to move one ton of product one kilometer, and the amount of carbon emitted by making and using that fuel – known as the fuel’s carbon footprint.
Much of the political attention is focused on the bottom line – which fuel is used and how carbon-intensive it is. But it will be more than 2030 before low-carbon fuels such as hydrogen or ammonia grow to a single-digit percentage of the transportation fuel used. Here’s the problem: If we’re to meet the goals of the Paris climate agreement, emissions must see dramatic reductions in the short term.
Four factors that affect shipping emissions, along with solutions to reduce those emissions. Author presented
This means we need to think about a wider range of ways to reduce shipping emissions in the coming decades. Here are ten places worth seeing:
1. Reduce the amount of fuel needed for transportation by transporting smaller items…
In a world with limited resources, do we need to think deeply about eating less – should we import containers of garden gnomes from China to the UK, for example, or should streetwear retailers continue to prioritize fast-fashion models over clothes? It’s been shipped halfway around the world, but it’s only designed to last for many uses.
2.…with a short distance…
The rise of 3D printing could see goods printed locally and on demand, so long-distance transportation may become important in the future. Because the new transportation fuels can be produced where they are needed, they only need to be shipped hundreds of kilometers instead of thousands.
3. …at low speed.
As ships move faster, they need more power. The bottom line is that going slow is one of the most effective and fastest ways to cut fuel use on ships. This can happen naturally due to high fuel prices, but locking these benefits requires action from the IMO, for example on ship speed limits.
4. Rearrangement of ships.
There are many ways to retrofit ships to use less fuel, such as protruding “bulb bows” to reduce drag from waves and upgrading ship propellers and hulls to improve fuel efficiency.
5. Use the wind…
Flattener rotors and spinning cylinders called giant kitesails are two technologies that use wind power to propel ships. This fuel consumption can be reduced by 10%. By combining this with computer programs to model wind speed and direction, it allows ships to optimize their routes, saving ships an additional 10% of fuel.
6. …and “shore-power”.
When ships are in port, they can use less fuel by turning off their engines and connecting to local power grids instead. This method of reducing air pollution in coastal cities is called “shore-energy”. Norway, the US and China are leading the way in implementing offshoring thanks to government support, but it’s less common in the UK – solutions to this are set out in this Tyndall Manchester research paper.
Next steps
7. Carbon accounting
Many alternative fuels produce low levels of carbon dioxide when burned. But emissions from their production must be properly accounted for, otherwise we shift pollution from one source to another. For example, hydrogen can be produced in different ways that lead to high or very low carbon emissions.
8. Carbon taxes
Attempts to decarbonize the shipping industry are rampant because standard marine fuels such as diesel are cheaper because they are not taxed globally. It’s time for the IMO to impose fees on carbon pollution, to make alternative fuels more competitive with traditional carbon-based ones. The proceeds will help fund research and development of new fuels and help developing countries decarbonize their shipping sectors.
9. Making a green policy
The UK could prioritize building zero-emission ships in its upcoming National Shipbuilding Strategy.
10. Strong framework
If the sector is to play its part in meeting the goals of the Paris Climate Agreement, all of the above mechanisms must operate within a clear framework to reduce overall shipping emissions. The IMO must set more stringent climate targets to deliver significant reductions over the next decade. In shipping, as in every sector, we need to do everything we can to reduce emissions as quickly as possible.
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