This month, teams from Japan and China have successfully extracted methane hydrate, a hydrocarbon gas trapped in a structure of water molecules, off the seafloor. The substance looks like ice but can be set on fire, and it’s energy-dense—one cubic meter of methane hydrate can contain 160 cubic meters of gas.

This makes searching for methane hydrate an attractive research project for several countries. According to the Department of Energy, methane hydrates are abundant on the seafloor and under permafrost, and they contain “perhaps more organic carbon that all the world’s oil, gas, and coal combined.”

Such vast reserves of fossil fuels are untapped because of how difficult it is to extract them. As a 2012 post from the Energy Information Agency (EIA) stated, until recently, methane hydrates “provided more problems than solutions.” Preventing their formation around deepwater oil and gas drilling operations has been a crucial part of planning ocean wells. The “ice” substance that contains the gas generally can’t just be picked up off the seafloor because it disintegrates outside of its high-pressure environment. The South China Morning Post wrote that current extraction efforts involve machinery “to depressurize or melt [the methane hydrate] on the sea bed and channel the gas to the surface.”

The most recent projects from China and Japan have been promising, although efforts to commercialize the technology are years away. The Straits Times said Chinese officials are hoping for commercialization before 2030, and Reuters reported that Japanese officials are hoping to commercialize methane hydrate-extracting technology between 2023 and 2027.

Methane hydrate is cleaner-burning than oil or coal, but it’s still a fossil fuel, so even if the fuel were able to be tapped cost-effectively it would still contribute to climate change. The value of methane hydrate would depend on what it replaces—if it drives down the cost of fossil fuels and makes it less attractive to develop renewable energy sources, that’s a step backward for a world that’s trying to put the brakes on warming. But if it could replace oil and coal consumption, especially in Japan and South Korea, which have few natural gas resources of their own, as well as in China and India, developing methane hydrate resources could be a positive move.

A challenge, however, is that before it's burned, methane is a more potent greenhouse gas than carbon dioxide, so care must be taken not to let the methane hydrate deposits warm or depressurize without a capture method.

The most recent successful test extraction was completed last week by Chinese researchers and announced by the China Geological Survey. The researchers used a platform oil rig in the South China Sea and were able to extract about 113,200 cubic meters of methane hydrate, with an estimated 99.5 percent methane content. The Straits Times says China is planning two or three more tests to study extraction methods.

The Japanese effort tapped methane hydrate off of Japan's central coast in early May. That study is ongoing. Japan has been pursuing methane hydrate extraction for some time, too. A study in 2013, "ended abruptly after less than a week due to problems with sand flowing into the well," according to Reuters.

The US also has a methane hydrate study underway in the Gulf Coast in partnership with the University of Texas. Drilling began on May 12, 2017.