This is scientific American 62nd Science.

I'm Julia Rosen.

Got a minute?

The Northwest is famous for its microbrews,

but the region's bubbles aren't just for beer.

Scientists have found plumes of the potent greenhouse gas methane

bubbling up from the sea floor off the coast of Oregon, Washington, and British Columbia.

The methane comes from rotting organic matter,

that is the waste and dead bodies of land and marine organisms.

They fall into the sediments and they decompose.

It's like a compost pile.

Paul Johnson, a marine geologist at the University of Washington.

Methane leaks out of this great compost pile all along the continental margin.

But Johnson says some plumes may originate in vast layers of frozen methane called hydrates.

Scientists worry that rising ocean temperatures may destabilize these deposits, freeing up even more methane.

And Johnson thinks he already sees evidence that it's happening. even more than a hundred

and Johnson thinks he already sees evidence that it's happening. Over the past few years, Johnson's team compiled a map of more than a hundred Northwest

Methane Seeps.

In a new study in the journal Geochemistry,

geophysics, geosystems, the researchers report a spike

in the number of plumes emanating from depths of about 500 meters.

That's the shallowest depth where frozen methane is stable,

...