Warming Arctic Waters Causes Methane Release
17.08.2009 - Water & Oceans, Other, Arctic
Researchers from the royal research ship RRS James Clark Ross (part of an International Polar Year initiative) have found that methane gas is being released from methane hydrate stored in the sediment beneath the Arctic seabed. Methane is a potent greenhouse gas co-responsible for climate change (over 100 years, the radiative forcing of methane is 25 times that of CO2).
Methane hydrate responsible for the methane gas release is an ice-like substance composed of water and methane which is stable (does not break up and release its content) at high pressure and low temperature. Whereas methane hydrate used to meet such conditions at 360 meters below zero, stabilization now occurs at depths of at least 400 meters. First analysis suggest that the warming by 1°C of the northward-flowing current over the last thirty years is the main cause for methane release along the West Spitsbergen continental margin.
While most of the methane currently released from the seabed is dissolved in the seawater before it reaches the atmosphere, methane seeps are episodic and unpredictable: significant outflows of methane into the atmosphere can occur quite suddenly. Methane dissolved in the seawater also contributes to ocean acidification.
“If this process becomes widespread along Arctic continental margins, tens of megatonnes of methane per year - equivalent to 10-15% of the total amount released globally by natural sources - could be released into the ocean”, says Graham Westbrook, Professor of Geophysics at the University of Birmingham.
