New Research Links Increase in Global Methane Flux to Potentially Massive Leak of Methane Gas From World-Wide Marine Sediments
By Robbie O'Donnell
(Wilmington, North Carolina) – Methane gas is one most prevalent greenhouse gases released into the Earth’s atmosphere by humans around the globe, and it also happens to be extremely damaging to global climate. In a 2010 study the EPA stated that, pound for pound, Methane has a 25 times greater effect on climate change then CO2 over a 100 year period. And now, a recent study shows that there is a potentially new, natural, source of methane being released at alarming rates around the globe; and its coming from almost 1,000 meters beneath the sea.
Dr. Adam Skarke of Mississippi State University and an interdisciplinary team of scientists recently published a paper in Nature Geosciences analyzing methane emissions in the US Atlantic Margin off the eastern coast of the United States. Skarke’s research team was made up of several geologists from the United States Geological Survey (USGS) and Mali’o Kodis, a National Oceanic and Atmospheric Sciences (NOAA) Hollings Scholar and student at Brown University.
Using multi-beam water column backscatter data Dr. Skarke and his team were able to identify almost 570 methane plumes over a 94,000 km2 area off the eastern coast of the United States. These plumes come from a “frozen”, solid form of methane referred to as a gas hydrate, that is solid and stable at a small range of temperatures and pressures beneath the sea. These gas hydrates can be found in marine sediments from all around the world and are actually a vital source of life for organisms who rely on the methane for their life processes.
Skarke and his team estimated that the total yield for methane gas hydrates in this margin was close to 614 trillion cubic meters2. This represents a massive, and detrimental, source of further methane gas emissions to the Earth’s atmosphere, on top of the already huge inputs from other methane emitters like melting permafrost and agricultural production. With increased global atmospheric and oceanic temperatures these hydrates will only continue to destabilize, increasing greenhouse gas concentrations and even adding to the acidification of the oceans. “Such seeps would represent a source of global seabed emissions that have not been fully accounted for in global carbon budgets”, say Skarke; making these hydrates especially hazardous moving into the future.
Humans could potentially further the release of these hydrates, especially here off the coast of North Carolina, by disturbing these sediments for oil and natural gas drilling. Because these hydrates are only stable at specific temperatures and pressures any change in the two, like the disruption of sediments due to drilling, would substantially increase the release of methane from the seafloor.
However, there is a silver lining. These hydrates represent a massive sink and storage resource for global carbon; and because they are not fully understood, could be a potential savior. With decreased average atmospheric and oceanic temperatures these hydrates would become stable and act as a virtual “prison” for methane in the oceans as it would be locked and stored in this solid hydrate form.
Robert O’Donnell (firstname.lastname@example.org)
UNCW Center for Marine Science