The leaks in two Russian gas pipelines in the Baltic Sea are spewing greenhouse gas emissions, raising fears that the disruption could cause a climate calamity - although to what extent is still unclear.
Neither of the pipelines was in operation, but both contained natural gas - which is mainly composed of methane, a potent greenhouse gas that is the second biggest cause of climate change after CO 2.
The impact to the climate will be disastrous and could even be unprecedented if these pipelines fail, said David McCabe, senior scientist at the Non-profit Clean Air Task Force.
McCabe said it was not yet possible to assess the size of the leak, given uncertainties around the pipe, how fast it is leaking, and how much gas would be absorbed by microbes in the water before reaching the surface.
McCabe said that the potential for a massive and highly damaging emission event is very worrisome because both of the Nord Stream pipelines contained mostly methane.
Over a 20 year timeframe, methane is more than 80 times the planet-warming potency of carbon dioxide, and roughly 30 times its potency over 100 years. Scientists say the reduction in methane emissions will be a key factor in the fight against climate change over the next few years.
Jasmin Cooper, a research associate at Imperial College London's Sustainable Gas Institute, said it would be hard to quantify how much gas was reaching the atmosphere, given scarce existing data on leaks from subsea pipelines.
Gazprom will probably have an estimate based on gas throughputs, but they need to send a team to measure and monitor how much gas methane is emitted into the atmosphere, she said.
Christian Lelong, director for climate solutions at Kayrros, said that methane leaks from onshore gas leaks can be picked up by a growing network of special satellites, but it is difficult to use satellites to analyze offshore leaks due to the different reflection of light on water.
Flyovers with planes or drones could be an alternative solution, analysts said.
A conservative estimate based on available data shows that the leaks were releasing more than 500 metric tons of methane per hour when first breached, with the pressure and flow rate decreasing over time, said Jean-Francois Gauthier, vice president of measurements at commercial methane-measuring satellite firm GHGSat.
In the United States, a huge Aliso Canyon gas leak in 2016 spewed around 50 tons of methane per hour at its peak. This would be an order of magnitude more, Gauthier said.