[eeyore]

Originally Posted by pressld2

You need to burn them to free the atoms from the molecules that they are currently in. A lump of coal is pretty inert and does not give off CO2 on it's own.

I takes ridiculously high temperatures to burn a diamond but yes, it too would produce CO2 if you did.

Dave P.

another really big outputter of Co2 is the manufacture of cement - the underlying issue being that you have to cause carbon to react with oxygen - or cause a carbon containing molecule to react with oxygen (in this case calcium carbonate (CaCo3) - being reduced to calcium oxide then calcium hydroxide. You dont necessarily have to "burn" anything for this to happen.