Greenhouse gases and arctic methane hydrate
With all the focus on global warming and greenhouse gases the question becomes how much of it has been caused by humans? NOAA researchers have discovered a large source of methane in the Arctic Ocean floor. Methane is a greenhouse gas that has been found to be close to 25 times more effective at trapping heat than carbon dioxide. This newly discovered source is just north of Norway and methane is constantly bubbling up from the ocean floor. Researchers say that a gradual warming of the regional ocean current has caused the temperature sensitive methane hydrate to break down and discharge gas from the seabed.
Methane hydrate typically forms beneath the seabed and is stable at depths below 300 meters. Scientists have collected sonar images of at least 250 plumes of methane gas rising from the ocean floor; these plumes are especially concentrated in the portion of the Gulf Stream that moves Atlantic seawater to the Arctic Ocean. This area has warmed by about 1 degree Celsius over the past 30 years causing the a decrease in the depth where hydrate is stable to 396 meters. It is believed that glacial cycles have been driven by hydrate formation and disintegration, and the resultant released methane in the atmosphere triggered climate-feedback effects. As our ability to study the ocean has grown, researchers have documented about 90 different oceanic locations of methane hydrate that are estimated to contain as much as 63,000 gigatons or more of carbon.
Similar methane deposits have been found in the ocean surrounding northern Alaska. There, scientists have paired with Coast Guard Arctic flights using a C-130 maritime surveillance aircraft. Since 2007 these flights have been carrying air-sampling instruments on the twice-monthly flights out of Kodiak over the Brooks Range to Barrow in the Arctic Circle. One of the airplane windows was replaced with an air inlet that is connected to onboard instrumentation that measures greenhouse gases and ozone in real time. These air samples are also stored and later analyzed in a lab in Boulder. Hopefully, this analysis will give scientists more insight into the distribution of many pollutants and trace gases.
Could this natural source of methane be a root cause of global warming?