What Is Combustible Ice?

It’s fairly common knowledge that methane is a damaging greenhouse gas (GHG), with a far shorter lifespan but far more powerful warming abilities than carbon dioxide (CO2). It’s also pretty well-known that methane can come from a variety of sources, including emissions from agriculture and dairy farming, landfill waste decomposition and coal mining processes.

However, methane can also be found deep underground, buried below the seabed or under layers of permafrost. Known as combustible ice, these frozen water-based methane hydrates have been recognised as a useful fuel source by Japanese and Chinese companies, who have decided to mine it as a viable method of renewable energy.

In plentiful supply

Theoretically, this form of methane will never run out and therefore is a renewable source of energy. That’s because it’s created by tiny single-celled microorganisms known as methanogens, which have no nucleus or other membrane-bound organelles in their composition and are a type of archaea.

After completing their metabolic processes, the methanogens release the methane hydrates into the ocean, where it is trapped by layers of sediment or permafrost. This potential fuel source was recently hit upon and a gargantuan store of the stuff was discovered underneath the Pacific Ocean, reaching a whopping 5,000 miles all the way from Hawaii to Central America.

Meanwhile, other stores have been discovered off the Asian landmass. Wasting no time, energy companies in China and Japan have set about mining these stores for use as a fuel source, with the former reporting success in extracting the hydrates from the floor of the South China Sea and the latter having similar joy off its Shima Peninsula.

Playing with fire?

Methane is, of course, extremely flammable. However, being located under sea, the chances of combustion are slim to impossible, because any explosion would require oxygen to occur – and anyone who has spent any length of times in the big drink will know that O2 is extremely hard to come by on the ocean floor.

However, that’s not to say that mining methane hydrates as a fuel source is a risk-free pursuit; indeed, the eventual consequences of doing so could be far more damaging than any underwater blaze. As a damaging GHG, extracting methane could be asking for trouble, since it’s almost inevitable that some will escape during the mining process.

Being 26 times more efficient at giving global warming a helping hand than CO2, it’s entirely possible that inadvertently releasing methane into the atmosphere could warm our oceans and melt permafrost just enough to release more methane… which could quickly turn into the most dangerous of snowball effects.

With huge concerns about the release of CO2 and nitrous oxides (NOx) from field warming experiments in the Arctic, it seems foolish to actively seek out more of this potentially catastrophic fuel source. Regardless, large-scale extraction is still probably around a decade from realisation, meaning this could all become moot – but even if the Chinese and Japanese manage to mine the methane without releasing any of it into the atmosphere, it will still be turned into CO2 in the combustion process. In any case, it doesn’t spell good news for the atmosphere.