Nord Stream Leaks Less Methane Than Estimated: Atmospheric Monitoring

The Nord Stream gas pipeline leak released about 70,000 metric tons of the powerful greenhouse gas methane, less than previously thought, researchers said Wednesday.

The Nord Stream 1 and 2 gas pipelines linking Russia to Germany have already been at the center of geopolitical tensions for months, with Russia cutting gas supplies to Europe in suspected retaliation to Western sanctions following Moscow’s invasion of Ukraine.

Then, last week, huge plumes of gas were spotted in the Baltic Sea above the pipelines, which NATO said was an act of sabotage.

Even though they weren’t working, they both still contained the gas, which was released through the water into the atmosphere.

Researchers from the French Atomic Energy and Alternative Energy Commission said they were “surprised” that data from monitoring stations across Europe led them to the conclusion that 70,000 tonnes of planet-warming methane had been released.

Other estimates, based on the estimated amount of gas in the pipes and pressure levels, resulted in estimates several times higher, they said.

Scientists have expressed concern about the climate and environmental impact of the leaks, which have largely stopped, but stressed that the amount of methane represents a tiny fraction of global emissions.

“These are important numbers,” said Philippe Siais, a researcher at the Laboratory of Climate and Environmental Sciences who led the latest French study.

He added that the amount of methane released was estimated to be equivalent to two percent of France’s carbon emissions, or that of Paris for the entire year.

“This is not very good news, but not a climate bomb,” said Philippe Siais, stressing that these initial findings should be verified by other modeling efforts.

Methane is responsible for about 30 percent of global warming to date, even though it is much less abundant in the atmosphere than CO2.

Gas plumes

The researchers used readings from stations of the European observation network Icos, which monitors the flow of atmospheric concentrations of greenhouse gases.

The data were then modeled against approximately 10,000 scenarios to obtain estimates for leakage.

With the wind, the smoke first rose towards southern Sweden and then turned west, where it was detected over parts of Norway and Great Britain.

Later, bursts of methane were faintly detected on the edge of western France in Brittany.

Siais said it was unclear why the leak would be less than previously thought.

One theory could be that there may have been less gas in the pipes than previously thought, he said, or that more than expected was dissolved in seawater, which is normal for less severe pipeline leaks.

The figures showed that emissions peaked on September 27th and then began to decline with a smaller spike on October 1st.

All four leaks were off the Danish island of Bornholm, two of which are in the neighboring exclusive economic zone of Sweden and the other two in the Danish one.

The Swedish Coast Guard said on Monday that it could no longer observe gas being released from the leak on the Nord Stream 1 pipeline, but bubbles from a smaller leak could still be seen above Nord Stream 2 on Monday afternoon.

Natural gas consists mainly of methane.

This is about 28 times more powerful than carbon dioxide on a hundred-year time scale, although it only lingers in the atmosphere for about a decade, compared to hundreds or thousands of years carbon dioxide.

© 2022 AFP