Why the IMO Must Tighten Rules On Shipping’s Carbon Emissions

 

The International shipping sector provides an outsized and growing contribution to the climate crisis. Slower, more efficient ships can help slash climate emissions, but this will not happen without ambitious regulation.

Fortunately, the International Maritime Organization’s (IMO) current revision of the rules around its Carbon Intensity Indicator, a metric for measuring and regulating ships’ carbon emissions provides such an opportunity. Governments are consulting and reviewing evidence on barriers to efficiency and potential solutions, with a final decision on improving the indicator due by January 1, 2026. 

If properly designed, these new rules could address almost half of shipping’s climate impacts and deliver massive ocean health co-benefits. But the outcome is far from certain.

The scope of the problem

The vast majority of internationally traded goods travel by ship, and these massive ships burn a lot of fuel. As a result, the shipping industry generates around three per cent of all climate emissions globally—a contribution equivalent to that of the whole economy of a country like Germany or Japan. 

Ships also undermine ocean health. I am not just talking about the environmental harm caused by oil spills when a tanker runs aground or sinks. As we have seen recently in the Black Sea this remains a very serious problem, but ships are also responsible for a myriad of other routine yet damaging operational practices—some legal, some not—that threaten ocean wildlife: oil and chemical discharges, toxic paint coatings, underwater noise pollution, sewage and grey water discharges, and the dumping of plastics, to name just a few.

Human health is also threatened, with an estimated 250,000 deaths and millions of childhood asthma cases annually caused by toxic air pollution from fossil-fuel powered shipping.

In all these areas, regulation has failed to keep up with the growth of the industry. Sporadic and weak measures mean the problem keeps getting worse.

Turning the page?

The Carbon Intensity Indicator revision provides the IMO with an important opportunity to address both the climate and ocean health impacts of global shipping and turn the tide on some of these problems.

By far the most effective way to reduce ship climate impacts is to slow ships down. A ten per cent speed reduction can lower the emissions of an individual ship’s journey by almost 20% per cent. Even though this will mean, in some cases, using additional ships, there are still large net emission reduction benefits. What’s more, slowing ships down can happen immediately—we don’t need new technology just to take our foot off the gas pedal. 

We must also look at wind power. In a case of “back to the future,” new high-tech sails can dramatically reduce fuel burn (and thus emissions) on existing ships, and can go even further when new ships are designed from scratch to use wind as their primary means of propulsion. No other transport mode can harness wind power directly in this way - it is shipping’s climate crisis superpower. 

Most underwater noise pollution is caused by ship propellers, compromising the ability of whales and other marine life to forage and reproduce. Using sails and slowing ships down has a dramatic effect on noise levels, and slower ships are also less likely to strike and kill whales and other marine wildlife. 

Any action that reduces the amount of fuel burned not only reduces climate emissions, but also cuts emissions of everything connected to burning fuel, including the particulates that are harmful to human health. The oily sludge that ship fuels generate, which sadly still often ends up being discharged illegally at sea, is also reduced. 

Reducing fuel burn also decreases the volume of toxic waste produced by the exhaust gas cleaning systems, known as scrubbers, that shipowners are installing to avoid using cleaner fuels. This shocking new waste stream is largely unregulated and dwarfs other shipping pollution in terms of volume.

An outsider looking in could easily assume that ship owners would operate their vessels more efficiently purely out of self interest and a desire to minimise costs, but there are a number of factors working against this.

For instance, there’s industry’s “split incentive” - whereby the entity responsible for the technical efficiency of a ship and its equipment isn’t always the one paying for the fuel. 

Inefficient ship operation is also often written into long-established conventions and contractual arrangements—the most famous one being the instruction in charter agreements to travel at "utmost dispatch” (quickly) and then wait at the destination if you get there too early. Slowing down and arriving on time would make more sense, and have a massive impact on climate emissions, but would also be a breach of the agreement.

And in a booming market when few ships are without work, an individual owner acting from a business perspective might prefer to speed up and squeeze in an extra trip. Unfortunately, this is the worst approach from a climate, environment and ocean health point of view.

It is rare that a single measure or regulation holds the potential to have such wide-ranging positive impacts on the climate and environmental footprint of an industry. The revision of the IMO’s Carbon Intensity Indicator truly holds the possibility to set the shipping industry on a much more sustainable course. 

This week’s IMO meeting, which is set to discuss the shipping sector’s impact on the global climate (Intersessional Working Group on Reduction of Greenhouse Gas Emissions from Ships - ISWG-GHG 18) must agree on an ambitious set of new climate measures, including a global zero- and near-zero GHG fuel standard, along with a levy on ship emissions to drive emission reductions and ensure a just climate transition for international shipping. 

However, to keep the cost of the shipping energy transition down and see to it that emission cuts happen quickly enough to meet the IMO GHG strategy’s 2030 and 2040 goals, these measures must be aligned with an ambitious, transparent and enforceable energy efficiency measure. To build a more ocean-friendly shipping industry, governments must close their ears to “special pleading” from industry and make sure both the fuel standard and levy align with the concurrent IMO’s Carbon Intensity Indicator revision, ahead of April’s Intersessional Working Group on Air Pollution and Energy Efficiency.

John Maggs is a board member of the Clean Shipping Coalition and is the coalition’s accredited representative at the International Maritime Organization.