The climate impacts of the Nord Stream gas leak are expected to be clearly more significant than the impacts on marine nature – the risk of chemical weapons dumped in the area will be investigated

News 2022-09-30 at 18:00

The methane leaking from the damaged Nord Stream pipelines is a powerful greenhouse gas with a significantly greater climate impact than the same amount of carbon dioxide. However, the direct impacts of the emissions on marine nature will be slight. There is some concern about chemical weapons that were dumped in the area in the past, and the risk caused by them will be investigated.

Direct impacts on marine nature are slight

The methane leaking from the Nord Stream gas pipelines is nearly insoluble in water and will therefore have very little effect on water quality. It may reduce the amount of oxygen in the water column and in the gas cloud generated above the water area.

Fish, marine mammals and birds in the leak area are either expected to die or – more likely – leave the area. However, the impact is limited to the sea area in the immediate vicinity of the leak. Although the leak areas are up to one kilometre in diameter, the affected area is small in relation to the surface area of the entire Baltic Sea.

The impacts of the event on marine life are minor and reversible. Once the leaks stop, aquatic organisms can return to the areas and the methane will no longer affect living conditions.

Still a lot of uncertainty about climate impacts

The most significant environmental problems caused by the leaks are the result of methane entering the atmosphere. Methane is a greenhouse gas that is nearly 30 times more powerful than carbon dioxide and thus significantly intensifies climate change.

Preliminary assessments related to the climate impacts of the leak vary greatly, because no one knows how much gas has been released or how long the leak might continue. The amount of methane released is more than Finland's annual methane emissions.

The risk of chemical weapons will be investigated

There is uncertainty concerning chemical weapons and other harmful substances that were dumped in the areas in the past and have accumulated in sediments on the sea floor.

The Bornholm Basin, where the gas pipeline leaks are located, is the single most significant chemical weapons dumping area in the Baltic Sea. However, the dumping areas identified at this time are several kilometres away from the explosion sites, so the impact that the explosions and leaks have on chemical weapons is assumed to be small. The Finnish Environment Institute and Finnish Institute for Verification of the Chemical Weapons Convention (VERIFIN) will continue to investigate the matter.

More information

Development Manager  Mika Raateoja , Finnish Environment Institute SYKE , tel. +358 295 251 536,

Impact on the marine environment

Research Manager Samuli Korpinen, Finnish Environment Institute SYKE, tel. +358 295 251 811,

Impact on the climate

Directror, Centre for Sustainable Consumption and Production, professor Jyri Seppälä, Finnish Environment Institute SYKE, tel. +358 295 251 629,


Communications Chief Aino Laine, Finnish Environment Institute SYKE, tel. +358 295 252 138,

Target group: