For the past 10 years, scientists have recorded 168 incidents of methane gas plumes in the Pacific Ocean off the coasts of Washington state and Oregon. A large number of the plumes were observed at a depth considered to be “critical,” in the stability of methane hydrate.
We already know about the role of carbon dioxide in global warming, but methane gas is also 25 times more potent as a greenhouse gas than CO2, according to the Environmental Protection Agency. Methane gas is emitted through both natural sources and human-caused activities, such as in the production of natural gas.
The findings by researchers at the University of Washington show that warming ocean waters a third of a mile below the surface, the exact depth at which frozen pockets of methane “ice” change over from a dormant solid to a greenhouse gas, could be causing more methane to be released than normal.
According to Science News Online, lead author of the study, H. Paul Johnson, a UW professor of oceanography said “We see an unusually high number of bubble plumes at the depth where methane hydrate would decompose if seawater has warmed. So it is not likely to be just emitted from the sediments; this appears to be coming from the decomposition of methane that has been frozen for thousands of years.”
Methane’s contribution to changes in climate in the past
It is known that methane gas has played a role historically in climate swings. Research has shown that climate changes in the past have led to the destabilization of methane hydrates and thus to the release of methane. The findings in ice core samples are still controversial, but they still are enough of a concern that the studies can’t be totally dismissed.
So while the new findings still have to be studied to determine any future impact on the Earth’s climate, it is known that much of the methane gas bubbling to the surface is gobbled up by marine microbes that turn it into CO2. This carbon dioxide in turn, results in low oxygen levels and a more acidic ocean. The researchers say this “tainted” water eventually makes it to the shorelines and into coastal waterways.
“Current environmental changes in Washington and Oregon are already impacting local biology and fisheries, and these changes would be amplified by the further release of methane,” noted Johnson in an American Geophysical Union (AGU) statement.
Gizmodo very bluntly assessed the results of the study, saying, “Sadly, this is yet another example of the wide-reaching effects of climate change—assuming, of course, that the researchers are correct in their assumptions.”
They pointed out that while the release of the methane gasses are in this case, not the result of human activity, it should still give us pause to think about other newly arising phenomenons, such as the Pacific Blob and the northern Atlantic ocean cold spot, because they surely are an indication that something isn’t right.
The study, “Analysis of bubble plume distributions to evaluate methane hydrate decomposition on the continental slope,” was accepted for publication in the journal American Geophysical Union on October 1, 2015.
