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The report makes for stark reading: if current emissions trajectories remain unchanged, it warns that the planet is on course to warm by about 3.2°C. Even if all existing national climate pledges are realised, warming would still not be limited to 1.5°C.
In other words, polluting industries have a lot of research and development work to do to ensure they contribute to emissions reductions. The IPCC highlighted aviation and shipping as two sectors where urgent progress is needed.
“While efficiency improvements (such as optimised aircraft and vessel designs, mass reduction, and propulsion system improvements) can provide some mitigation potential, additional CO2 emissions mitigation technologies will be required,” wrote the report’s authors.
Newbuild vessels needed
The largest container ships can carry upwards of 20,000 containers – and the quantity of heavy fuel oil (HFO) needed to propel these vessels is similarly vast. Ocean-going container ships are designed to have a lifespan of a decade or more, which means that low-carbon newbuild vessels need to become the norm rather quickly. The International Maritime Organisation (IMO), the UN agency responsible for regulating shipping, has called for at least a 50% reduction of CO2 emissions from 2008 levels by 2050.
Environmental campaigners have decried the target as lacking in ambition. Figures from last year show that vessels powered by liquefied natural gas (LNG) made up 13% of the newbuild vessel order book. The shipping industry has come to favour the fuel for its purported air quality and carbon-reduction benefits.
While it’s true that LNG-fuelled vessels produce far fewer emissions of harmful pollutants such as nitrogen oxides and sulphur oxides, research has shown that they still have harmful carbon footprints. The issue is that methane (which makes up more than 90% of the content of LNG) is known to escape, or “slip”, across its supply chain. The IMO has estimated that between 0.2% and 3% of methane escapes from ship engines during the combustion process and is released to the atmosphere.
Because methane is thought to be 80 times more climate-warming than CO2 over a period of 20 years, this presents a clear problem for the decarbonisation of shipping. The organisation Transport & Environment has claimed that about 80% of LNG today is burned in an engine with worse total greenhouse-gas emissions than traditional marine engines running on HFO. The industry evidently needs credible alternative fuel sources – and fast.
Green fuels
For its part, the IPCC has suggested that green hydrogen, ammonia and biofuels could be important technologies – with electrification proving practical only on smaller vessels that travel short routes. Meanwhile, University Maritime Advisory Services, based at University College London, said in a recent report that green hydrogen and green hydrogen-derived ammonia are “the only scalable fuels that can achieve the emission reduction targets set forth in the Paris Agreement”.
However, hydrogen-powered ships aren’t yet commercially ready, although there are several advanced pilot projects in the works. The Norwegian group Wilhelmsen is developing two hydrogen-powered ro-ro vessels that will travel short routes. Another Norwegian shipping firm, Northern Xplorer, unveiled a concept for a hydrogen-powered cruise ship last year. Ammonia-powered ships are in a similarly early stage of development, although a Greek shipowner did take delivery of an “ammonia ready” tanker in January.
There are logistical challenges that must be overcome before low-carbon ship fuels are readily available. The IPCC suggested that policymakers should implement stricter efficiency and carbon-intensity standards to incentivise the development of greener ships.
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