The ruptures on the Nord Stream natural gas pipeline system under the Baltic Sea have led to what is likely the biggest single release of climate-damaging methane ever recorded, the United Nations Environment Programme (UNEP) has said.
A huge plume of highly concentrated methane, a greenhouse gas far more potent but shorter-lived than carbon dioxide, was detected in an analysis this week of satellite imagery by researchers associated with the UNEP’s International Methane Emissions Observatory, or IMEO, the organisation said on Friday.
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“This is really bad, most likely the largest emission event ever detected,” Manfredi Caltagirone, head of the IMEO for UNEP, told Reuters.
“This is not helpful in a moment when we absolutely need to reduce emissions.”
Researchers at GHGSat, which uses satellites to monitor methane emissions, estimated the leak rate from one of four rupture points was 22,920kg (around 50,000 lbs) per hour. That is equivalent to burning about 630,000 pounds (around 286,000kg) of coal every hour, GHGSat said in a statement.
“This rate is very high, especially considering it’s four days following the initial breach,” the company said.
The IMEO tweeted on Saturday that new data appears to indicate that the leakage of methane appears to be diminishing.
“New analysis of data provided by the satellite Sentinel2 today indicates a significant reduction in the estimated diameter of the methane plume – from 520m to 290m. A similar reduction is also observed in the estimated concentration of methane leaked in the pipeline rupture,” the IMEO said,
📌New analysis of data provided by the satellite Sentinel2 today indicates a significant reduction in the estimated diameter of the methane plume – from 520m to 290m.
A similar reduction is also observed in the estimated concentration of methane leaked in the pipeline rupture.📉 pic.twitter.com/35muTsGTyU
— International Methane Emissions Observatory (@CH4Observatory) September 30, 2022
At least two underwater blasts, likely packing the force of a bomb blast “corresponding to an explosive load of several hundred kilos” of explosives, caused this week’s leaks in Baltic Sea gas pipelines, the governments of Denmark and Sweden said.
The blasts measured 2.3 and 2.1 on the Richter scale, resulting in four leaks, venting gas into the sea. Two of the leaks are in Danish territory; another two are in Swedish territory.
In a statement on Friday to the UN Security Council, the two countries noted that the gas plumes being vented were disrupting air and sea vessels and could be dangerous to marine life. Additionally, greenhouse gas is being released into the environment.
The leaks could continue through at least Sunday.
“All available information indicates that those explosives are the results of a deliberate act. Such acts are unacceptable, endanger international security and give cause for our deep concern,” the statement read.
Sweden’s coastguard also reported on Friday that the amount of gas leaking from the breach in its exclusion zone had diminished, after observing the situation from the air.
The coastguard also pointed out that ships in the areas should now keep a safe distance of 7 nautical miles, (just under 13km), rather than 5 nautical miles, as previously requested.
The total amount of methane leaking from the Gazprom-led pipeline system may be higher than from a major leak that occurred in December from offshore oil and gas fields in Mexican waters of the Gulf of Mexico, which spilled about 100 tonnes of methane per hour, Caltagirone said.
The Gulf of Mexico leak, also viewable from space, ultimately released about 40,000 tonnes of methane over 17 days, according to a study conducted by the Polytechnic University of Valencia and published in the journal Environmental Science & Technology Letters.
Improved satellite technology has rapidly enhanced the ability of scientists to find and analyse greenhouse gas emissions in recent years, something some governments hope will help companies detect and prevent methane emissions.
The major leaks that suddenly erupted in the Nord Stream gas pipelines that run from Russia to Europe have generated plenty of theories but few clear answers about who or what caused the damage.
Both Russia and the European Union have suggested the ruptures were caused by saboteurs.
Europe and the United States have heaped sanctions on Moscow in retaliation for its invasion of Ukraine, raising worries the Kremlin will seek to deprive Europe of crucial energy supplies leading into the winter.
Caltagirone said, whatever the cause, the damage to the pipeline posed a problem beyond energy security.
“This is the most wasteful way to generate emissions,” he said.