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Rising methane from the Nord Stream 2 leak
Photo: Danish Defense/UPI Photo/IMAGO
According to a study by Chinese scientists, the explosions at the Nord Stream 1 and 2 gas pipelines are unlikely to have a negative impact on the global climate.
Nevertheless, incidents of this kind must be prevented in the future, the researchers from the Chinese Academy of Sciences report in the journal "Advances in Atmospheric Sciences".
In the paper published on Friday, the experts refer to an analysis of high-resolution satellite images, according to which up to 220,000 tons of methane gas escaped into the atmosphere during the accident in the Baltic Sea.
The team then simulated possible effects on the climate on the computer.
The warming caused by the emitted methane is so minimal that it "cannot be perceived in ecosystems or in human society," explained study leader Xiaolong Chen.
At the same time, the researcher warned: If humanity wants to achieve the goals of the Paris climate agreement, "damage to infrastructure like this should be avoided."
Largest documented methane disaster
At the end of September, explosions tore several holes in the pipelines in the Baltic Sea.
After the detonations, large amounts of gas escaped continuously for days from several leaks.
There is a suspicion of sabotage.
According to the Chinese researchers, the accident was the largest documented methane emission of this kind in human history.
In the previously largest gas accident in 2015 at California's underground gas field Aliso Canyon, only about half as much gas escaped.
Methane is the second largest driver of global warming after CO₂.
In the long term, the gas is about 25 times more harmful to the climate than CO₂, but is emitted in smaller quantities.
The information on the amount of methane released, on which the current calculation is based, is of a similar magnitude to an estimate made by Gregor Rehder, Professor of Marine Chemistry at the University of Rostock and researcher at the Leibniz Institute for Baltic Sea Research Warnemünde (IOW), shortly after the incident for SPIEGEL.
According to this, an estimated 328,000 tons of methane gas were stored in the damaged tubes of Nord Stream 1 and 2, which could potentially have leaked into the environment.
This corresponds to around 17 percent of Germany’s annual methane emissions in 2021.
"That's a considerable amount of greenhouse gas that can be emitted if everything actually escapes," said Rehder at the time.
However, IOW experts did not reckon with any noticeable consequences of climate change either: "The climate process will not be changed as a result," explained Rehder's colleague Oliver Schmale.
The crucial problem: long-term escaping methane
The Chinese researchers now write that the global oil and gas industry alone would have emitted up to 70 million tons of methane annually between 2008 and 2017.
The gas escaping from the pipelines accounts for just one day of the sector's annual emissions.
Sönke Zaehle from the Max Planck Institute in Jena considers the methods used in the study to be well-established, although there are more complex procedures - both for estimating the amount of methane and for forecasting the climate impact.
He also shares the assessment of the climate impact: Ultimately, the decisive factor for the ever-increasing amount of methane in the atmosphere is not the short-term leaks in the Nord Stream tubes, but that there are many sources that emit methane for a long time and therefore would have a significant overall impact.
In addition to fossil sources, this also included wetlands such as the thawing permafrost soils.
The latter fuel a self-reinforcing system: if the ground thaws and methane is released from it, this increases the global temperature rise, which in turn causes the ground to thaw and further methane emissions to be emitted.
jme/dpa