NASA Earth Observatory image modified by SkyTruth
Mapping Methane Emissions from LNG Vessels at Sea
Say No to LNG is a global campaign working to debunk the myth that Liquefied Natural Gas (LNG) is a “climate-friendly” marine fuel alternative, instead revealing its true nature as a toxic and climate-damaging fuel. The campaign partnered with SkyTruth in early 2024 to reveal the dangers of LNG emissions at sea.
Liquefied Natural Gas (LNG) is typically composed of 85 – 95% methane, which is 80 times more potent than carbon dioxide as a greenhouse gas over a 20-year time frame.
LNG-fueled vessels release unburned methane into the atmosphere during transit – termed methane slip (the “slip” referring to gaseous unburned methane escaping into the atmosphere). A recent study found that the most common type of engine on LNG-fueled ships releases an average of 6.4% methane slip, nearly twice the assumed 3.1%-3.5% of European Union regulations and the International Maritime Organization (IMO), the United Nations body responsible for regulating international shipping.
Image courtesy of Say No to LNG Campaign.
Additionally, LNG tankers emit methane plumes, occasionally large enough to be classified as super-emitter events, when their cargo is unloaded at port. These plumes are estimated to have greater emission rates than methane slip, posing serious environmental risks to our rapidly warming planet. However, as a colorless and odorless gas, methane emissions can be difficult to visualize. That is why Say No to LNG asked SkyTruth to create a visual representation of the scale of LNG traffic to relay the global impact of this dangerous fossil fuel.
Graphic ©SkyTruth. Data Credits: LNG tanker AIS data from Global Fishing Watch, 2024; Methane plume data from Carbon Mapper Inc. Contains modified imagery © 2021 Planet labs Inc. All rights reserved, reprinted with permission.
SkyTruth created the map above to visualize global LNG vessel traffic throughout 2023. The map illustrates the various routes of all LNG tankers, including the Diamond Gas Rose, which traveled approximately 85,000 kilometers in 2023–enough distance to circle the globe twice.
In 2021, this same tanker was observed releasing a 5,800 kg/h plume of methane while at port, likely during the transfer of its cargo to or from the onshore LNG storage facility. SkyTruth’s map helped Say No to LNG illustrate the global surge in LNG vessel traffic, and to advocate at the IMO for international regulations for methane emissions from shipping.
“Shipping regulators like the International Maritime Organization (IMO) need to establish regulations that reflect the actual scope of the shipping sector’s methane footprint”, said Say No to LNG’s Global Director Elissama Menezes. “Mapping technologies are changing the invisibility of methane emissions associated with LNG vessels into something that can be seen and understood.”
Methane’s concentration in our atmosphere has doubled over the last two centuries. In the European Union, consumption of LNG by ships has doubled from 2.2 million tonnes (Mt) in 2018 to 4.4 Mt in 2022, increasing methane emissions from vessels and exacerbating global warming.
With the gas industry attempting to brand LNG as a “climate-friendly” alternative, resources like SkyTruth’s map are particularly needed.
“Maps are a unique way to demonstrate the interconnectivity of LNG shipping emissions and the need for a global solution,” said Menezes. “Just one vessel can travel to so many different countries, touching countless seemingly disparate communities. Combining mapping technologies with the latest research on the real dimension of methane emissions from shipping provides a powerful visual narrative to take action.”
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