redOrbit Staff & Wire Reports – Your Universe Online
Natural processes, not global warming, are primarily to blame for the dissolution of the fragile, ice-like solid fuel substances known as methane hydrates, according to new research published online Thursday in the journal Science.
Methane hydrates, which are composed of water and methane, are only stable in high pressure and low temperature conditions, the study authors explained. In some areas, such as in the North Atlantic off the coast of Svalbard, scientists have detected gas flares regularly, but the reason for this phenomenon was unclear.
One hypothesis suggested that climate change might be helping to cause the dissolution of gas hydrates. However, over the past several years, an international team of researchers have discovered it is very likely that these gas flares are actually caused by natural processes.
“In 2008, when we observed the outgassing of methane for the first time, we were alarmed,” explained lead author Christian Berndt of the GEOMAR Helmholtz Centre for Ocean Research Kiel. “The gas originates from depths where the hydrates should normally be stable. But we knew that a relatively small warming might melt the hydrates.”
Berndt’s team conducted a series of expeditions over several years to help discover the source of the outgassing. One of the more commonly accepted assumptions was these regions of the North Atlantic were being affected by global warming. However, investigations conducted using a German search sub suggested otherwise.
“On one hand, we have found that the seasonal variations in temperature in this region are sufficient to push the stability zone of gas hydrates more than a kilometre up and down the slope,” the professor said.
“Additionally, we discovered carbonate structures in the vicinity of methane seeps at the seafloor,” added Dr. Tom Feseker from the MARUM Center for Marine Environmental Sciences in Bremen. “These are clear indicators that the outgassing likely takes place over very long time periods, presumably for several thousand years.”
However, the authors are quick to point out that this does not mean that climate change plays no role on the potential release of methane on the Svalbard-area seafloor. They explain that, over the course of time, deep oceans will also become warmer – especially in the polar regions, which are home to vast quantities of methane hydrate.
“As a powerful greenhouse gas methane represents a particular risk for our climate. A release of large amounts of the gas would further accelerate global warming,” Berndt said. “Therefore, it is necessary to continue long-term monitoring, particularly in such critical regions as off Svalbard.”