The mysterious Nord Stream pipeline explosions sent methane levels in the Baltic Sea rocketing to 1,000 times higher than normal, a new study has revealed, as fears grow over underwater sabotage linked to Russia.
Deep-sea blasts rocked the Russia-to-Germany gas pipelines in 2022, releasing what scientists say were “unprecedented amounts” of methane into the water and atmosphere. The new findings, made with an underwater robot known as a glider, reveal the gas spread far across the Baltic Sea, with the fallout stretching from the Danish coast to the Polish port of Gdansk.
Ocean currents carried the methane into 23 protected marine areas, say researchers at the University of Gothenburg and Swedish foundation Voice of the Ocean. More than 14 per cent of the entire Baltic Sea was affected while detectives in Denmark, Sweden and Germany made unsuccessful efforts to find the culprit against the backdrop of the war in Ukraine.
Before the pipeline was built the chance of Nord Stream being ruptured had been rated as an “extremely unlikely”, once-in-20,000-years event. However, a spate of incidents involving Baltic Sea infrastructure means “impact assessments for subsea pipelines must be adapted to the current geopolitical context”, the scientists wrote in a paper published on Wednesday.
Nato's top generals were holding talks in Brussels on Wednesday as Baltic states deploy drones and warships to monitor the sea for cable saboteurs. The military chiefs were told by Nato Secretary General Mark Rutte that hostile actions by Russia “are accelerating” in the form of “cyber attacks, assassination attempts, acts of sabotage and more”.
“We used to call this hybrid. But these are destabilisation actions and campaigns,” Mr Rutte said. “Russia is hard at work to try to weaken our democracies and chip away at our freedom.”
Russia denied involvement in the Nord Stream blasts, dismissing the idea it would damage an export route to Europe for state-owned gas giant Gazprom. Others suspected a Kremlin ploy to cause a gas shortage in Europe or send a warning to the West, but none of Ukraine's allies have come forward with concrete evidence against Moscow.
Theories that Ukrainian or US operatives were involved have also been put forward and it was revealed last year that German prosecutors were seeking the arrest of a Ukrainian diving instructor. Ukraine and the US both denied any role in what would have been a high-risk act of sabotage in the waters of western allies.
Scientists said their new findings were the “most robust estimates to date” of the environmental fallout of the explosions. They said methane levels in the Baltic Sea were as high as 1,000 times above normal after the 2022 explosions, with unusual concentrations measured in some areas even several months later.
The "major environmental impact" came from increased greenhouse gas emissions, but shock waves from the explosion are also feared to have affected endangered porpoises. Eight Baltic states said warned of a “significant risk to the marine environment” from undersea sabotage in a joint statement on Tuesday.
Researchers “feel confident that we have a really good picture of how the methane spread in the Baltic Sea, both across time and space”, said Bastien Queste, an oceanographer at the University of Gothenburg. “We now know the areas where the methane emission may have had an impact,” he said. “It will be easier to determine whether a future problem in the Baltic Sea ecosystems, for example, is related to the Nord Stream leak or not.”
