Last week countries agreed to a new emissions reduction target for the shipping sector, as part of a wider climate deal.

The headline target, agreed at an International Maritime Organization (IMO) meeting in London, is to peak and then reduce greenhouse gas emissions “at least 50%” by 2050, compared to 2008 levels. This is the first-ever international climate goal for the shipping sector.

Carbon Brief highlights the main things to know about the the new deal.

Absolute target

Most significant is the fact that the new climate deal includes an absolute emissions reduction target for shipping. It also calls for emissions to be phased out completely, though without any timeline. This is shown in the third point from the agreed strategy, below.

Many countries were pushing for more ambitious targets, arguing that the 50% goal is not in line with the Paris Agreement. However, other countries wanted to avoid any kind of absolute goal, setting only a carbon intensity target. Therefore, many were happy that an absolute goal had been set.

Significant step forward in the global efforts to tackle climate change: international shipping to cut emissions by at least 50% by 2050. Important contribution to the #ParisAgreement. Our statement: https://t.co/TCYvg4eUbq #MEPC72 pic.twitter.com/ldoInVeKa5

— Miguel Arias Cañete (@MAC_europa) April 13, 2018

However, several countries, including Brazil, the US and Saudi Arabia, “reserved their positions” on endorsing this part of the deal, arguing it is still too early to set an emissions reduction goal for the shipping sector. Their reservations will be included as an annex to the deal.

It is also significant that the language targets all GHGs, not just CO2, as some countries had been pushing for.

Countries also agreed to reduce the carbon intensity per tonne of goods shipped by at least 40% by 2030, compared to 2008 levels, and to continue implementation of a previously agreed mandatory energy efficiency design index (EEDI) for new ships.

Ratchet

The inclusion of the words ”at least” in the emissions reduction goal was crucial for getting Pacific island states on board with the deal. This is because it leaves the door open for a ratcheting up in future to be in line with the Paris Agreement’s 1.5C goal.

The @IMOHQ just adopted a historic strategy to reduce greenhouse gas emissions. But our job is far from over. Here are my final words on the #MEPC72. Now its time to call @President_Heine and my kids to tell them the good news. The Pacific & #HighAmbitionCoalition got this done. pic.twitter.com/6Vwm2KmwoK

— David Paul (@MinisterDPaul) April 13, 2018

The strategy states that the goal is “subject to amendment depending on reviews”. These reviews will take into account future reports of the Intergovernmental Panel on Climate Change (IPCC), the strategy says. This would include the IPCC special report on the impacts of 1.5C warming, set to be released later this year.

Common but differentiated responsibilities

Another important point of contention was the inclusion in the strategy of the principle of “common but differentiated responsibilities” (CBDR). This is a central principle enshrined in the UN Framework Convention on Climate Change (UNFCCC), which says that developed and developing nations have different levels of responsibility in some aspects of the effort to fight climate change.

Inclusion of this in the deal was seen by some to be at odds with the IMO’s principle of “no more favourable treatment’, which says every ship from every nation should be treated the same.

In the end, both guiding principles were included in the climate strategy. However, it remains to be seen how they will be reconciled.

The US delegation – which opposed the resolution, but did not stop it going through – refused to endorse the inclusion of the principle of CBDR in the agreement, along with several other elements of the strategy.

Next steps

While an overall target was agreed last week at the IMO, many details remain to be negotiated. Therefore, the IMO agreed for an additional intersessional working group session to take place before its next environmental committee meeting in six months time.

There is still much to be decided: the initial strategy proposes a host of measures which could be implemented in future, including a programme to help promote uptake of alternative low-carbon fuels, market-based measures (MBMs) to cut emissions, and enhanced energy efficiency measures.

The IMO is also set to adopt a “revised” GHG strategy in 2023. This is set to include short-, mid- and long-term “further measures” for reducing emissions, along with an implementation schedule.

The final publicly available version of the IMO’s new strategy is published in full below.