The Danish Energy Agency said the pipeline operators had told it that the three sections of damaged pipe contained 778 million cubic meters of natural gas. If all that gas reaches the atmosphere, it would be equivalent to about 1/1,000th of estimated annual global methane emissions, according to calculations by scientists with the U.S. Geological Survey’s Gas Hydrates Project.
From an emissions perspective, the breach is “an important one to watch,” said Carolyn Ruppel, chief of the project, who made the estimate with a colleague, Bill Waite. A worst-case calculation by Thomas Lauvaux, a researcher with the Laboratory of Climate and Environmental Sciences in France, equated it to what comes from about 1 million cars in a year.
Speaking on behalf of the 27 nations of the European Union, E.U. foreign policy chief Josep Borrell vowed a “robust and united response” to any attacks on the bloc’s energy infrastructure.
Though investigations into the simultaneous leaks in the Nord Stream pipelines have only just started, sabotage appears the most likely cause, policymakers said. Many blamed Russia, which is waging a war in Ukraine and has been using energy supplies to Europe as leverage against the continent.
“There is reason to be concerned about the security situation in the Baltic Sea region,” Bodskov said in a statement after meetings at NATO. “Russia has a significant military presence in the Baltic Sea region, and we expect them to continue their saber rattling.”
Some politicians said they believed the explosions were a threat. “These incidents show that energy infrastructure is not safe,” Viktorija Cmilyte-Nielsen, speaker of Lithuania’s Parliament, told a local radio station on Wednesday. “It can be interpreted as a warning.”
Danish and Swedish authorities detected two underwater disturbances Monday and reported three breaches on the Nord Stream 1 and 2 pipelines. Seismologists in Denmark and Sweden said the blasts did not appear to be caused by earthquakes, landslides or other natural activity.
Flemming Larsen, managing director of the Geological Survey of Denmark and Greenland, went a step further Wednesday, saying the agency is “quite confident that the tremors were caused by explosions.”
It was not immediately clear how European nations would respond. One European official, speaking on the condition of anonymity to offer a candid assessment, said proof is needed before imposing sanctions, “and for proof you need to have an investigation,” which takes time.
Sanctions are not the only option open to bloc. Its responses could range from accelerating a cutoff of Russian energy deliveries to sending patrol boats into the Baltic Sea to help bolster pipeline security, the official said.
But opposition from some E.U. governments could make punitive action difficult, said Federico Santi, a Europe analyst with the Eurasia Group. “It seems the sabotage was designed to limit the scope for retaliation,” he noted.
New sanctions were announced Wednesday, but they were unrelated to the damaged pipelines and were instead triggered by Russian President Vladimir Putin’s staged referendums in Ukraine, his threats on nuclear weapons and his partial military mobilization of his own citizenry.
Kremlin spokesman Dmitry Peskov labeled accusations that his country was behind the explosions as “predictably stupid” and “absurd.” He told reporters on a call that Russia has no interest in damaging the pipelines — which are majority-owned Russian entities — because of the high value of the gas.
Peskov also suggested the U.S. government was behind the blasts, pointing to President Biden’s comment in February that “there will be no longer a Nord Stream 2” if Russia invaded Ukraine.
A U.S. official, speaking on the condition of anonymity to discuss a sensitive matter, said the United States had nothing to do with the attack on the Nord Stream pipelines, calling the idea “preposterous.”
Many European governments are now putting their energy infrastructure on heightened alert, though none said there were indications of direct threats.
“After what happened in the Baltic Sea, the Norwegian armed forces will be more present and more visible in areas around our oil and gas installations,” Norwegian Prime Minister Jonas Gahr Store said.
Satellite imagery reviewed by The Washington Post showed a mass of methane bubbles spanning roughly 13 miles in diameter that first appeared on the surface of the sea on Monday morning. The image was taken before the second blast was recorded by seismic sensors.
It is not clear what role satellite technology will play in the investigation. Imaging can provide a more clear picture of the location of the leaks, but that location — in a cloudy region, over water — makes it tougher to understand their scale and scope.
According to Lauvaux, one Swedish monitoring station in Hyltemossa, northwest of the breach and downwind on Tuesday from the Danish island of Bornholm, near the breaches, has picked up significant spikes in methane concentrations since Tuesday afternoon.
Most of that gas has already left the pipelines, Kristoffer Bottzauw, managing director of the Danish Energy Agency, said at a news conference Wednesday. Not all of it will reach the atmosphere — some of it mixes with water and stays under the water line.
“My gut feeling is, probably the majority of that methane would have come out in a huge volume so quickly it wouldn’t have been absorbed,” said Drew Shindell, a professor of earth science at Duke University and a leading expert on emissions. But he said that compared with total global methane emissions, “this is a tiny blip. It’s not a huge volume.”
Birnbaum reported from Washington. Emily Rauhala in Karsto, Norway, Robyn Dixon in Riga, Latvia, Beatriz Rios in Brussels, Martin Selsoe Sorensen in Copenhagen and John Hudson in Washington contributed to this report.