On September 26, 2022, leaks were discovered in the Nord Stream 1 and 2 underwater gas pipelines, located near Denmark and Sweden. Both pipelines belong to Russia and were built to transport natural gas from Russia to Germany via the Baltic Sea. Officials said the leaks were caused by deliberate action, not accidents, and were likely intentional sabotage. While the accusations have multiplied, the motives for the damage are not yet known.
Seismic disturbances in the Baltic Sea were detected and officials said that while neither pipeline was carrying gas at the time of the explosions, they still contained pressurized methane, which is the main component of natural gas. The methane has now spewed out, producing a wide stream of bubbles on the sea surface that are visible from various satellites in Earth orbit.
Private company GHGSat, which has active satellites monitoring methane emissions from space, rotated its constellation of high-resolution satellites to measure the pipeline leak. According to a statement from the European Space Agency, GHGSat tasked its radar and microwave satellites to obtain measurements at wider viewing angles and was able to target the area where sunlight reflected the strongest on the surface. sea surface – known as the “reflection point”.
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What they discovered was that on September 30, the estimated emission rate, as shown by his first measurement of methane concentration, was 79,000 kg (174,000 pounds) per hour, which making it the largest methane leak ever detected by GHGSat from a single point source. GHGSat said that rate is extremely high, especially since this image comes four days after the initial breach, and is only one of four breakpoints in the pipeline. In a press release, the company said that amount of methane is equivalent to more than 90,000 kg (2 million pounds) of coal burned in one hour.
The ESA said that “monitoring methane over water is extremely difficult because water absorbs most of the sunlight in the shortwave infrared wavelengths used for remote sensing of methane. . This limits the amount of light reaching the sensor, making it extremely difficult to measure methane concentrations above the sea at high latitudes. Cloud cover contributed to the difficulty of making satellite observations of this event.
Although methane partially dissolves in water and is not toxic, it is the second most abundant anthropogenic greenhouse gas in our atmosphere, responsible for climate change.
“The power of active microwave radar instruments is that they can monitor ocean surface signatures of methane bubbling through clouds over a wide band and at high spatial resolution overcoming one of the main limitations of optical instruments,” said the ESA Ocean and Ice Scientist. , Craig Donlon. “This helps establish a more complete picture of the disaster and the associated timeline of events.”
From then on, other Earth observation satellites equipped with optical and radar imaging instruments were called upon to characterize the bubbling gas leak in the Baltic.
Planet Labs’ Planet Dove satellite showed a bubbling disturbance in the Baltic Sea ranging from 500 to 700 m above the water’s surface.
Other satellites have seen these views of the area:
Several days later, a significant reduction in the estimated diameter of the methane disturbance was observed when draining gas from the pipelines. This animation from the Copernicus Sentinel-2 satellite confirms this, since it shows views of September 30 and October 3, 2022.
Here is a map of the area where the pipelines are. Although the leak is no longer a threat, the repercussions of this disaster remain.