HomeLow carbon futureWhy aren’t we talking about the climate impact of shipping?

Why aren’t we talking about the climate impact of shipping?

Transport is centre stage in the ‘how to reverse climate change?’ debate. It’s the biggest carbon emitting sector in the UK and one where action has been far too slow. But things are slowly changing, for instance with the zero emissions vehicle mandate and the increase in charging facilities for road vehicles. But why do we never hear about shipping?  As a sector it is consistently overlooked in climate news, even though international shipping is responsible for approximately three per cent of global carbon emissions (that’s more than international aviation). Given this level of emissions is equivalent to that of Germany, it is time to pay more attention to shipping.  

The UK does have an ambition to be “home to a world-leading zero emissions maritime sector”. And the good news is that our shipping emissions have decreased in recent decades, largely due to the reduced demand for crude oil, which makes up a large proportion of cargo transported by ships. But the bad news is that, if more action isn’t taken soon, global shipping emissions are projected to grow by up to 250 per cent by 2050, depending on future demand and energy use.  

Calculation of shipping emissions is misleading
A perception problem is that shipping emissions attributed to the UK are not the whole picture. How international emissions from this sector are allocated to a country is contentious.  

The UK tends only to measure its domestic shipping emissions, but this is roughly half of the emissions the UK is truly responsible for. If, instead, emissions from international vessels that refuel at UK ports were included, the UK’s shipping emissions show a much larger problem.  

That’s why it was encouraging to see the UK’s commitment to the Clydebank Declaration at the COP26 climate conference last year, promising to establish zero emission maritime routes, between at least two ports, known as ‘green corridors’. A further announcement followed, that international shipping emissions will be included in the UK’s sixth carbon budget, placing a legally binding cap on them from 2033.  

However, targets alone will not reduce emissions. The Department for Transport  appears to be limiting its focus on shipping’s domestic climate impact, and leaving international emissions reductions to the International Maritime Organization (IMO), judging by the recently closed consultation. To its credit though, at COP26 the UK called for the IMO to set a zero emissions target for 2050. The current aim of a 50 per cent reduction by 2050 would miss the goal to limit global temperature rise to 1.5˚C.  

The EU, meanwhile, is getting ahead. It has set an example by bringing forward its shipping decarbonisation goals and has announced a ‘Fit for 55’ package, aiming to cut shipping emissions 55 per cent by 2030. And, from 2023, maritime emissions (including half of those generated from shipping between EU nations) will be included in the EU’s Emissions Trading Scheme.  

On top of this, the EU has announced the Fuel EU scheme from 2025 which will require all large passenger and cargo ships to be more energy efficient.  

The UK could take inspiration from this. For example, it could set a mandate for green shipping fuels to increase their use. Or it could implement the government’s recent consultation proposal to include maritime emissions in the UK Emissions Trading Scheme, including all the international emissions the UK is responsible for.   

Quick improvements are possible
Success will come from striking the right balance between improving fuel efficiency in the short term, reducing demand for shipped items and encouraging the use of more sustainable fuel in the medium term, which still needs more innovation to be viable.  

There are several ways to make quick efficiency improvements over the long lifetime of large vessels. These can be as simple as regularly cleaning hulls or reducing ship speed; and as complex as ‘pre-swirl devices’, which are attached to propellors to maximise water flow and increase thrust.  

As we have highlighted before, lowering UK emissions by reducing overall the number of products we ship and consume would help to improve resource efficiency and is an effective way to protect the economy from resource supply volatility.  

Heavy Fuel Oil has to be phased out
Fuel development is a trickier subject. The shipping industry is dominated by the use of Heavy Fuel Oil (HFO), a dense but high carbon source of energy. This needs phasing out, even to achieve the IMO’s target to cut international shipping emissions in half by 2050. But alternatives have their own challenges. Liquified Natural Gas (LNG) has grown in popularity for commercial vessels. But, while it decreases CO2 emissions to some extent, it also contains large amounts of methane, a more potent greenhouse gas in the short term than carbon dioxide. Green hydrogen is a promising zero emission fuel but is very expensive to transport and produce. Fuel cell technology (which also uses hydrogen but is like a battery that doesn’t need charging) might overcome this problem but is only viable for short journeys. Green methanol, derived from biological sources, can contribute to deforestation and still emits carbon when used in an internal combustion engine. Green ammonia is zero carbon, but it is highly toxic and dangerous to store onboard. It also has the potential to change into nitrous oxide, which is also a more potent greenhouse gas than CO2.   

Although the Department for Transport is starting to take action, for instance by recently launching round three of the clean maritime demonstration competition, providing £60 million between 2023 and 2025 for the development of better fuel, it should also be reaching for the short term solutions now. This is one sector where the new government could make a mark as an international role model, particularly by capitalising on UK competitive advantage in zero emissions fuel technology. 

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