By John Roach
Methane appears to be bubbling up from more than 500 vents on the Atlantic Ocean floor off the U.S. East Coast, according to a new study in a finding that could have profound long-term implications for the global climate.
While scientists suspected these so-called seeps existed there, until now they lurked undetected. Their discovery suggests similar seeps exist throughout the world’s oceans.
The seeps come from gas hydrates, an ice-like combination of water and methane that forms naturally with extreme cold and depth in the ocean. Methane is a potent greenhouse gas, and gas hydrates are thought to hold up to 10 times as much carbon as the earth’s atmosphere.
The seeps were discovered in a stretch of ocean waters from Cape Hatteras, N.C., to Georges Bank, Mass. The majority are located at a depth of about 1,640 feet, which is at the upper level of stability for gas hydrate.
“Warming of the ocean waters could cause this ice to melt and release gas,” Adam Skarke, a geoscientist at Mississippi State University and the study’s lead author, told NBC News. “So there may be some connection here to intermediate ocean warming, though we need to carry out further investigations to confirm if that is the case,” he added…
…Within the next 100 years or so, any major impact on the global climate from methane, which is about 20 times more potent than carbon dioxide, will come from methane emitted from tropical wetlands and human activities, not the oceans, noted David Archer, who studies the global carbon cycle and global climate at the University of Chicago.
“In the timescale of centuries to hundreds of thousands of years, (gas hydrate) is clearly a significant amplifier,” he told NBC News. “But in terms of the climate of just the coming century, the actual forcing of climate from the rise in atmospheric methane due to this, I think, will be small.”
Continue Reading at NBC News…