Report: LNG as marine fuel is worse than business as usual for the climate

January 28, 2020

Shocking new analysis exposes underestimated methane emissions from LNG ships; challenges LNG’s contribution to international emissions reduction goals

London, UK — A new report from the International Council on Clean Transportation (ICCT) has found that the most popular Liquefied Natural Gas (LNG) ship engine, particularly for cruise ships, emits between 70% and 82% more life-cycle greenhouse gas (GHG) emissions over the short-term compared to clean distillate fuels. The shocking new report comes as the shipping sector grapples with its enormous climate footprint, and more ship operators are turning to LNG as a purported climate solution.

The ICCT report examines the lifecycle GHG emissions from marine fuels, including a previously poorly understood source of climate emissions from LNG-powered ships — the unintentional releases of the climate super-pollutant methane from ship engines, known as methane slip. The authors found that using LNG could actually worsen the shipping industry’s climate impacts compared to marine gas oil (MGO) when considering the amount of heat these emissions will trap over a 20-year period.

“This groundbreaking new analysis is a damning climate indictment of LNG as marine fuel. For a sector that is already one of the largest contributors of global greenhouse gas emissions, this report reveals that switching ships to LNG is worse than doing nothing. This should serve as an alarming wake-up call for the International Maritime Organization, which must act now to ensure it includes all greenhouse gas emissions in its emissions reduction strategy,” said Kendra Ulrich, Senior Shipping Campaigner at

LNG is being hailed as a climate solution by many in the shipping industry — a sector that is responsible for more global GHG emissions than major climate polluting nations, including Germany, Iran, South Korea, and Canada. If left unchecked in a business-as-usual scenario, international shipping GHG emissions could rise from its current 3% share of emissions to a staggering 17% of global GHG emissions by 2050. If ships were to continue to uptake LNG as a marine fuel, emissions could be even worse.

The report shows the need for adopting policies that can reduce the broader GHG emissions of shipping instead of CO2 only, including the well-to-tank emissions of ship fuels. If we fail to include all GHGs and focus only on CO2, we might end up with a large number of ships fulfilling all efficiency requirements, but where the GHG savings are on paper only,” said Dr. Elizabeth Lindstad, Chief Scientist at SINTEF Ocean, Maritime Transport.

The Intergovernmental Panel on Climate Change has warned that global GHG emissions must be nearly halved from 2017 levels by 2030 to avert the worst impacts of climate change, and methane emissions from all sources must be cut by at least 35% from 2010 levels by 2050.

Given this short timeframe to drastically reduce climate-disrupting pollution, the report authors evaluated the climate impacts of marine fuels using 20-year and 100-year global warming potentials. Methane emissions are particularly problematic because methane traps 86 times more heat than the same amount of carbon over a 20-year period.

Of the 756 LNG ships currently in use or on order, the most popular engine type, by far, is also the worst offender with the highest rate of methane slip. This engine is especially popular with cruise ships, and the cruise industry promotes these LNG ships as having significant climate benefits. As recently as December, the largest cruise operator in the world, Carnival Corporation, touted its LNG program as an example of its climate leadership in an announcement about joining the “Getting to Zero Coalition.” This coalition aims to have zero-emission vessels in operation by 2030.

“Carnival Corporation’s program to increase the number of LNG ships in its global fleet is like jumping out of the oil pot and into the climate-fueled fire. While most of Carnival’s global fleet still burns one of the dirtiest fossil fuels on earth — heavy fuel oil — LNG is far from a solution to its massive climate pollution problem. We urge Carnival to stop fueling its ships with oil refinery waste and end its investments in climate-disrupting LNG ships. If Carnival wants to be an environmental leader, it must switch to the cleanest fuel available — marine gas oil — and put its investment dollars toward truly zero-emissions technologies,” said Ulrich. 

The UN International Maritime Organization’s (IMO) Pollution Prevention and Response Subcommittee meets February 17-21 in London, in what is being hailed by the international community as an Arctic Summit. The pollution subcommittee will be asked to send strong recommendations to its parent committee, the Marine Environment Protection Committee, on urgent control measures for black carbon in the Arctic and other marine ecosystems.

Also on its agenda are banning the use, and carriage for use, of heavy fuel oil in the Arctic, and closing a loophole that allows for the continued use of heavy fuel oil under more stringent fuel sulfur standards if ships install “emissions-cheat” systems called scrubbers.

The Marine Environment Protection Committee meets March 30-April 3 in London, where, after two years of stalling and delays, its top priority will be its Greenhouse Gas Reduction Strategy and agreeing to short-term measures to begin reducing emissions.


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