By AFP - Agence France Presse
Methane leaks from Nord Stream pipeline explosions reviewed: studies
A series of underwater explosions that ruptured the Nord Stream gas pipelines in 2022 caused the largest methane leak ever recorded in a single incident, according to new research published on Wednesday.
Scientists estimate that the rupture of the main pipeline for transporting Russian gas to Europe released approximately 465,000 tons of methane into the atmosphere - well above previous estimates, but only a fraction of total global emissions.
The exact cause of the explosions in September 2022, a few months after Russia invaded Ukraine, is still unknown, although Moscow and Kiev have exchanged accusations about this and other damage to energy infrastructure.
In three new studies on the Nord Stream spill - one in Nature and two in a separate journal, Nature Communications - the researchers stated that its possible impact on the environment and climate is still unclear.
But the leak “represents the largest recorded amount of methane released in a single transient event,” wrote Stephen Harris and others in Nature.
Although significant, this leak was equivalent that year to 0.1% of man-made methane emissions, a powerful greenhouse gas many times more effective at trapping heat in the short term than carbon dioxide.
Methane is emitted naturally by wetlands and rivers, but also by cows, rice fields, and landfills.
One of the main sources of man-made emissions is oil and gas projects, and fixing leaking pipes and other infrastructure is considered a particularly cost-effective way of rapidly slowing down global warming.
“Although extraordinary in their magnitude, the Nord Stream explosions remind us of the immediate climate opportunity represented by reducing methane emissions across the oil and gas sector,” said Manfredi Caltagirone, head of the United Nations Environment Programme's International Methane Emissions Observatory (IMEO), which supported the research.
- Uncertain impact
After the explosions under the Baltic Sea damaged the Nord Stream pipelines, the gas began to bubble up at four rupture points, creating huge blobs of foam on the surface.
There was an “immediate desire” among scientists to determine the size of such a significant leak, said IMEO's Harris.
This was a challenge because it was difficult to know how much methane was absorbed by the ocean and how much leaked into the atmosphere.
Early estimates of the Nord Stream leak ranged from 70,000 to 300,000 tons.
For the research in Nature, the scientists used atmospheric data, satellite images, marine observations, and aerial measurements to model the amount of methane that may have escaped from the ocean.
The leak “far exceeds” any other leak of its kind and was equivalent to 30% of Germany's annual methane emissions, wrote Friedemann Reum, from the German Aerospace Center, in Nature Communications.
Another article in the same journal analyzed the impact of the spills on marine protected areas in the Baltic.
Martin Mohrmann, from Sweden's Voice of the Ocean Foundation, and his colleagues suggested that 14% of the region had methane concentrations five times higher than average levels.
More than 150 countries have signed a pledge to reduce methane emissions, but atmospheric concentrations of this potent greenhouse gas still reached record levels in 2024.
The International Energy Agency noted that normal oil and gas operations around the world release the same amount of methane as the Nord Stream explosion every day.
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