SEATTLE, Dec. 10 (UPI) -- If it wasn't for the ocean, global warming might be having a more profound effect than it already is. The ocean acts as a sort of heat sink, sucking up the atmosphere's excess heat and greenhouse gases. But a warming ocean has consequences, too -- melting ice caps, rising ocean acidity, and now apparently the release of tons of methane gas.
According to new research, as the lower depths of the ocean warm, carbon deposits are melting and releasing methane. Recent testing by scientists at the University of Washington showed that ocean temperatures are rising considerably at depths of roughly one-third of a mile beneath the surface -- the same area where methane turns from a solid to a gas.
"A lot of the earlier studies focused on the surface because most of the data is there," explained co-author Susan Hautala, an associate professor of oceanography at Washington. "This depth turns out to be a sweet spot for detecting this trend."
The new study estimates that as much as four million metric tons of methane has been released from deposits off the coast of Washington State from 1970 to 2013 -- 500 times the normal rate of release. Methane isn't as abundant as CO2, but it is more efficient at trapping heat.
"Methane hydrates are a very large and fragile reservoir of carbon that can be released if temperatures change," researcher Evan Solomon said in a press release. "I was skeptical at first, but when we looked at the amounts, it's significant."
Researchers say the warming water likely originates in the Sea of Okhotsk, an expanse of salt water between Russia and Japan. When warming surface water there becomes dense it begins to spread out across the Pacific, pulled under to intermediate depths by ocean currents. The same trends affecting Washington's coast are likely influencing methane deposits along the coasts of Northern California and Alaska, researchers say.
The new study was published this week in the journal Geophysical Research Letters.
