(Bloomberg) -- The 700-meter wide pool of bubbling water in the Baltic Sea caused by the rupture of the Nord Stream gas pipelines points to a climate disaster.
It’s the most visible of three major gas leaks emanating from the pipelines connecting Russia to Europe. Germany estimated that about 300,000 metric tons of methane, one of the most powerful greenhouse gases, entered the atmosphere as a result of the releases. That amount of the gas would have roughly the same climate impact over a 20-year period as the annual emissions from about 5.48 million US cars.
The cause of the three near-simultaneous pipeline ruptures hasn’t been confirmed, but German and US officials said the incident looked like sabotage.
While the Nord Stream 1 pipelines were halted -- and Nordstream 2 had never even started -- they all contained pressurized natural gas, the vast majority of which is methane. Germany’s Federal Environment Agency said its calculation for how much methane was emitted was based on estimated filling status and volume information from the two pipelines.
“There are no containment mechanisms on the pipelines, so the entire contents of the pipes are likely to escape,” the FEA said in a statement.
Methane has 84 times the warming power of carbon dioxide during its first 20 years in the atmosphere but degrades quickly after that. When assessing the climate impact of methane leaks scientists typically convert methane into CO2 equivalent using either a 20-year global warming potential factor or they may multiply the gas by its global warming potential over 100 years.
Germany, using the 100-year conversion factor, said the Nord Stream leaks were roughly equivalent to 1% of the country’s total annual emissions.
Two of the three leaks occurred in Denmark’s exclusive economic zone, which is international waters and close to the Nordic country’s Baltic Sea island of Bornholm. Officials there have said that far more than half of the gas in the ruptured pipelines had already escaped into the Baltic Sea and expects most of the remaining gas to have left the pipelines by this coming Sunday.
The methane emissions will be equal to about 32% of Denmark’s annual greenhouse-gas discharges, Kristoffer Bottzauw, head of the Danish Energy Agency, said in a briefing on Wednesday in Copenhagen.
Estimating the precise amount of methane that has escaped into the atmosphere is an extremely challenging task. Many so-called super-emitting events -- large continuous discharges of methane -- are captured by satellite imagery over land-based pipelines or fossil-fuel production sites. But capturing accurate data over water, is far more challenging given light reflects off the surface.
Read this QuickTake on the impact of methane on the atmosphere
There are a number of other key uncertainties -- how much gas was in the pipelines at the time, what temperature and pressure it was being held at, and just how big the size of the rupture in the pipes was. Even when the gas escapes, some is likely to have dissipated into the water, but that also depends on the density of microbial life, as well as the depth. To obtain accurate readings, a plane would probably have to take measurements from the air.
Despite that, scientists on social media were quick to do some back-of-the envelope calculations into just how much methane might have escaped. Andrew Baxter, director of energy strategy at the Environmental Defense Fund, estimated that around 115,000 metric tons of methane escaped.
The largest known release in the US, happened at gas storage facility in Aliso Canyon, Los Angeles, in 2015, where an estimated 97,100 metric tons of methane was emitted over several months. By comparison, the Nord Stream leaks may have happened over the course of several hours.
GHGSat Inc., a satellite emissions monitoring company, said that the breaches of the Nord Stream pipelines may have resulted in 500 metric tons of methane escaping per hour -- 10 times more than the Aliso leak at its peak.
Other scientists said that while the Nord Stream leaks were a disaster for the climate, they still pale in comparison to daily discharges from gas infrastructure globally, where around a tenth of the fossil fuel’s supply is leaked into the atmosphere, according to Piers Forster, a professor of climate physics from the University of Leeds in the UK.
“The most direct effect of these gas leaks on climate is the extra dollop of the powerful greenhouse gas methane,” said Dave Reay, executive director of Edinburgh Climate Change Institute. “That said, this is a wee bubble in the ocean compared to the huge amounts of so-called ‘fugitive methane’ that are emitted every day around the world due to things like fracking, coal mining and oil extraction.”
While methane leaks are harmful to the climate, they do not pose a significant threat to the marine environment, the German Environment Ministry said in response to a request for comment, highlighting previous cases where the gas was discharged due to drilling in the North Sea. It added that they were exchanging information with experts from Denmark and Sweden.
The expulsion of methane, comes amid growing public consciousness of its effects on the climate. At the COP26 summit in Glasgow, Scotland, over 100 countries pledged to drastically curb emissions. The EU is also in the process of legislation that would raise the obligation on companies to reduce flaring of the gas, conduct regular inspections to stem leaks and boost transparency of leaks associated with imports.
At an event in the European Parliament Tuesday evening to launch “methane week,” lawmakers, scientists and environmentalists discussed how to measure the scale of the leak, but were united on one thing -- it is likely to be an environmental disaster. The Green group’s co-lead negotiator for the bloc’s methane regulation, Jutta Paulus, pointed the finger firmly toward Russia, coming the same week as the Baltic Pipeline -- connecting Norway to Poland -- was opened.
“‘I don’t think it’s a coincidence that this is happened on the day the Baltic pipeline was opened,” Paulus said at the event. President Vladimir Putin is telling us “be sure you know what you’re doing when you’re applying more sanctions on us. We have to use all possibilities to apply energy efficiency and ramp up renewables.”
(Updates with German methane estimate in second paragraph, Denmark estimate in eighth paragraph and details throughout.)
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