A new leak in the open sea. A fourth leak, in the Swedish zone, has been identified in the Baltic Sea above the Nord Stream gas pipelines by the Swedish coast guard. It adds to the three already known in this part of the Baltic: two on the Danish side and one on the Swedish side, which cause significant bubbling of sea water on the surface, over areas ranging from 200 meters to one kilometer of diameter. This is the gas escaping from the pipes.
These gas pipelines were not in service, but according to different estimates, they contained between 150 and 300 million cubic meters of gas, mainly methane. These pipelines can completely empty in the space of a few days, indicates Antoine Rostand, the boss of Kayrros, a company which quantifies methane leaks into the atmosphere. Problem: this methane has a warming power 80 times greater than that of CO2.
>> Nord Stream 1 and 2 gas pipelines: what is the impact of methane leaks on the climate?
This leak can thus have consequences on our greenhouse gas emissions, according to an estimate by Greenpeace, these leaks risk adding the equivalent of eight months of greenhouse gas emissions to the atmosphere in Denmark.
This is bad news. And at the same time, it is unfortunately a quantity to put into perspective since it is only the equivalent of a single day of emissions from the oil and gas industry, due to accidental leaks during oil changes or repairs. A few months ago, scientists from the CNRS and the CEA also identified, from space, 1,200 plumes of methane which correspond to leaks from oil and gas operations. These leaks were seen and tracked by satellite: even if methane is an invisible gas, it can indeed be spotted from space at certain wavelengths, by playing with the radiation from the sun. In terms of pollution, these leaks from the oil and gas industry are comparable, each year, to the circulation of 20 million vehicles.
Finally, the methane partially dissolves in the water, thus limiting its impact, but it all obviously depends on the type of ecosystem present: at this place in the Baltic, there is relatively little oxygen and little marine life. So far, the Danish and Swedish authorities want to be reassuring.