Nord Stream Pipeline Rupture Caused Largest Methane Leak Ever Recorded, UN-Study Finds

A new study coordinated by the United Nations Environment Programme (UNEP) has found that the rupture of Europe’s Nord Stream gas pipelines more than two years ago resulted in the planet’s largest human-caused release of methane, a potent greenhouse gas.
Published on Wednesday, Jan. 15, 2025, the study revealed that up to 485,000 metric tons (485,000 tonnes) of methane seeped from the pipeline network following a series of explosions under the Baltic Sea in September 2022, more than double previous estimates.
The Nord Stream leak was already considered one of the largest human-caused methane releases in history. The UNEP analysis, published in the journal Nature, reveals its true scope for the first time.
The leak was nearly five times larger than the previous record holder, a release from the Aliso Canyon natural gas storage facility in the United States. Experts say that over the short term, the Nord Stream leak contributed as much to global warming as 8 million cars driven for a year.
“This release was extraordinary in its magnitude, but it’s just the tip of the iceberg,” said Manfredi Caltagirone, head of the UNEP-led International Methane Emissions Observatory.
“Despite their massive size, the Nord Stream explosions represented just two days’ worth of the global oil and gas industry’s methane emissions. There is an enormous opportunity to address this pollution, which is supercharging the climate crisis.”
Methane, often a byproduct of oil and gas production, is responsible for about one-third of global warming. While it remains in the atmosphere for about a decade, it traps heat more than 80 times more effectively than carbon dioxide.
Previous studies estimated the Nord Stream leak to be between 75,000 and 230,000 metric tons (tonnes). The UNEP analysis, coordinated by the International Methane Emissions Observatory, used atmospheric data, satellite images, marine observations, aerial measurements and engineering estimates to gauge how much methane dissolved into the Baltic Sea and escaped into the atmosphere.
The analysis included the only on-site airborne measurements collected from the explosions, gathered by the German Aerospace Center and Technische Universität Braunschweig.
Nearly 70 scientists from 30 research organizations participated in the study, which concluded that the leak's “plausible range” was between 445,000 and 485,000 metric tons (tonnes).
“The observatory’s work showcases that using different observation and estimation tools is essential to enabling the assessment of the magnitude of emissions, a first step towards prioritizing actions to reduce methane emissions,” said Andrea Hinwood, UNEP’s chief scientist.
The Nord Stream study is part of a larger UNEP effort to understand and reduce methane emissions. This includes the Methane Alert and Response System, which uses satellite data to track major methane releases from oil and gas installations and notifies governments and companies.
The UNEP’s Oil and Gas Methane Partnership 2.0 also helps oil and gas companies measure and report their emissions.
With methane emissions are rising faster than at any time since the 1980s. The Intergovernmental Panel on Climate Change has called for countries to cut releases by at least 30% by 2030 to keep alive the Paris Agreement goal of limiting the Earth’s temperature rise to 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels.