Natural gas is the third major form of fossil fuel.
It's methane, mostly.
Basically, you can get natural gas from either
the coal peat kind of organic carbon.
or from the plankton oil source kind of organic carbon.
As long as it's heated up enough.
It cooks and forms some methane.
Because methane
is a gas,
it's more difficult to transport, than either oil or coal,
because it has to be held in a pressurized container
For that reason, the price of
natural gas varies hugely, from place to place, around the world.
There are places in the world where natural gas is worth basically nothing.
It comes out as a by-product of getting oil and they just
burn it rather than try to keep it.
methane is the most reduced form of carbon.
It has the most energy per carbon released and
it also tends to burn more cleanly than either
coal, which makes these aerosols and little particles in the atmosphere,
or oil, which tends to leave reactive compounds that make urban smog.
For those reasons
methane is called a cleaner fuel than oil, or or coal,
but it's still a fossil fuel and it's still releasing carbon to the atmosphere.
Most of the major gas reserves on Earth
are found underneath an impermeable cap kind of rock, either permafrost,
like in Siberia, or salt deposits from evaporated sea water in the Middle East.
there's also vast amount of methane in a very spread out and probably mostly
inaccessible form known as methane hydrates in
ocean sediments, very spread out.
But there could be thousands
of gigatons of methane as methane hydrates.