Temperature changes in the Gulf Stream are “rapidly destabilizing methane hydrate along a broad swathe of the North American margin,” the experts said in a study published Wednesday in the peer-reviewed journal Nature.

Using seismic records and ocean models, the team estimated that 2.5 gigatonnes of frozen methane hydrate are being destabilized and could separate into methane gas and water.

It is not clear if that is happening yet, but that methane gas would have the potential to rise up through the ocean and into the atmosphere, where it would add to the greenhouse gases warming Earth.

The 2.5 gigatonnes isn’t enough to trigger a sudden climate shift, but the team worries that other areas around the globe might be seeing a similar destabilization.