Traditional landfills have exhaust pipes dug into them to release methane as it is produced.

In the process it releases methane that was previously adsorbed to the coal surface and that may be recovered.

The practice appears to have reduced the activity of soil bacteria that release methane, and emissions have dropped 40 percent.

But as paper degrades underground it releases methane, a potent "greenhouse gas" that is warming the atmosphere.

So energy from the cram bombs goes into the seabed and warms up ice that's just below the freezing point, releasing methane.

Since methane is removed from the Martian "air" very fast, there needs to be a current source that releases fresh methane still today.

Bison and buffaloes are examples of animals that release methane.

Removing water from the coal bed reduces pressure and releases methane.

It is releasing methane from the tundra, and could also release it from the seabed.

This was the second such drilling at Mallik: the first took place in 2002 and used heat to release methane.