Satellites have captured a plume of environmentally damaging methane streaming from the ruptured Nord Stream 1 and 2 gas pipelines, near Denmark and Sweden.
Neither pipeline was transporting gas at the time of the blasts, but they still contained pressurised methane which spewed out producing a wide stream of bubbles on the sea surface.
Satellite measurements captured the scale of the enormous leak.
The organisation GHGSat, a leader in methane emissions monitoring from space and also part of the European Space Agency's Third Party Mission Programme, tasked its satellites to measure the Nord Stream 2 gas pipeline leak.
GHGSat used a constellation of high-resolution (around 25m) satellites.
By tasking its satellites to obtain measurements at larger viewing angles, GHGSat were able to target the area where the sun’s light reflected the strongest off the sea surface – known as the ‘glint spot’.
On 30 September, the estimated emission rate derived from its first methane concentration measurement was 79,000 kg per hour.
It is the largest methane leak ever detected by GHGSat from a single point-source. This rate is extremely high, especially considering its four days following the initial breach, and this is only one of four rupture points in the pipeline.
GHGSat director for Europe, Adina Gillespie, said: “Predictably, the media and the world have turned to space to understand the scale of the Nord Stream industrial disaster.
“While we await further investigation on the cause, GHGSat responded quickly, measuring 79,000 kg per hour of methane coming from the leaks. We will continue tasking GHGSat satellites for the Nord Stream sites until we no longer detect emissions.”
Claus Zehner, Copernicus Sentinel-5P, Altius and Flex missions manager, mentioned: “Besides GHGSat, the Copernicus Sentinel-2 satellite provided methane concentration measurements emitted by this pipeline leak which highlights the feasibility to use both public funded and commercial satellites in a synergistic way.”
Although methane partly dissolves in water, released later as carbon dioxide, it is not toxic, but it is the second most abundant anthropogenic greenhouse gas in our atmosphere causing climate change.
ESA’s scientist for ocean and ice, Craig Donlon, said, “The power of active microwave radar instruments is that they can monitor the ocean surface signatures of bubbling methane through clouds over a wide swath and at a high spatial resolution overcoming one of the major limitations to optical instruments. This allows for a more complete picture of the disaster and its associated event-timing to be established.”
Although optical satellites can provide us with the radius of the methane bubbling over water, they provide little information on how much methane has been released into the atmosphere.
Monitoring methane over water is extremely difficult as water absorbs most of the sunlight in
As large as it may be, the Nord Stream release pales in comparison with the 80 million tonnes emitted each year by the oil and gas industry. The latest release is roughly equivalent to one and a half days of global methane emissions.
A study earlier this year showed that while carbon dioxide tends to make the headlines – countries need to focus on methane to make an impact on the climate.
The Duke University study compared two approaches to climate change - one cutting just CO2 emissions, and another cutting a broad range of greenhouse gases.
The study found that if reductions of methane and other overlooked gases were cut as well as CO2, the rate of global warming could be halved by 2050.
Co-author Drew Shindell, Nicholas distinguished professor of Earth Science at Duke University said, "Decarbonisation is crucial to meeting our long-term climate goals, but it's not enough.
"To slow warming in the near-term and reduce suffering from the ever-increasing heatwaves, droughts, super-storms and fires, we need to also reduce short-lived climate pollutants this decade."
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