One of the large Nord Stream gas leaks bubbling up out of the Baltic sea, taken 28 September 2022. Photo: Supplied/ Swedish Coast Guard
Ruptures of 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) says.
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 (IMEO), the organisation said.
"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."
GHGSat is an organisation that uses satellites to monitor methane emissions, and its researchers estimated the leak rate from one of the four rupture points was 22,920kg an hour.
That was equivalent to burning about 285 tonnes (630,000lbs) 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 total amount of methane leaking from the Gazprom-led pipeline system could be higher than from a major leak that occurred in December from offshore oil and gas fields in Mexican waters off the Gulf of Mexico, which spilled about 100 metric tons of methane per hour, Caltagirone said.
The Gulf of Mexico leak, also viewable from space, ultimately released about 40,000 metric 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.
That is the equivalent of burning 501,858 tonnes (1.1 billion lbs) of coal, according to the US Environmental Protection Agency's Greenhouse Gas Equivalencies Calculator.
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 is undergoing a fuel crisis, partly fed by geopolitical tensions, and both 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.
-Reuters
