By Lynda Williamson
The Japanese state-owned oil and gas company JOGMEC has announced that they have successfully extracted methane hydrate, known as 'ice gas', from marine sediments 300m beneath the seabed in the Nankai Trough approximately 80km off Japan's southern coast.
There is believed to be enough gas in this small test site to meet the country's needs for the next eleven years and the Japanese government hopes that the project will be commercially viable within 5 years.
On a wider scale, the state oil company said that: "Methane hydrates within Japan's territorial waters may well be able to supply the nation's natural gas needs for a century."
This breakthrough could be the answer to Japan's prayers as the country has seen its trade surplus rapidly slip following the closure of 52 of its 54 nuclear power plants after the Fukushima nuclear disaster in 2011. Since then it has had to use expensive imports of Liquid Natural Gas which has put its economy at a disadvantage.
The US Geological Survey estimates that methane hydrates deposits could contain twice as much carbon as all other fossil fuels on earth but warns that the ecological impact is "very poorly understood."
Methane hydrate is a naturally occurring form of methane gas combined with water which produces a crystalline substance containing very high concentrations of methane. It is found extensively throughout the world, among other places in major river deltas such as the Amazon Delta as well as in ocean sediments and in the sediments in and beneath areas of permafrost.
Methane gas is approximately 20 times more potent as a greenhouse gas than CO2 so any leakage of methane into the atmosphere would raise global temperatures by considerably more than an equivalent amount of CO2. Methane is faster acting and shorter lived than CO2, remaining in the earth's atmosphere for only 10 years as opposed to CO2 which remains for approximately 100 years.
Some climate scientists believe that methane played a major role in the Paleocene – Eocene thermal maximum which represents one of the most rapid and extreme warming events in geological history. Core samples taken from old ocean sediment layers point to short periods of rapid warming of up 8 degrees centigrade on top of longer term rises of between 5 and 7 degrees centigrade. The most likely cause of this rapid global warming over a short period is the release of methane into the atmosphere.
Temperature and pressure conditions determine methane hydrate stability so global warming can have the effect of releasing more naturally occurring methane into the air. Some scientists have pointed to plumes of methane rising from the floor of the Arctic Ocean as evidence that increased global temperatures could trigger the release of large quantities of methane.
The worry is that positive feedback could lead to a tipping point, a kind of vicious circle where the release of methane raises temperatures and the raised temperatures stimulate methane release. Professor Euan Nisbet from Royal Holloway, London, explains that:
"The Arctic is the fastest warming region on the planet, and has many methane sources that will increase as the temperature rises. This is yet another serious concern: the warming will feed the warming."
Other scientists point to storms and fluctuations in weather systems, which could produce changes in ice coverage, as an explanation for Arctic gas plumes.
Speaking to Newsnet Scotland, Dr Richard Dixon, Director of Friends of the Earth Scotland said:
"The last thing we need is more fossil fuels. It is deeply ironic that methane hydrates are becoming more accessible because of climate change, since burning them would set us on a course to truly disastrous climate change. The planet cannot afford Japan or anyone else to extract gas from methane hydrate deposits."