Which is more eco-friendly cremation or burial?

Cremation. Burial involves concrete liners, so it's never really 'ashes to ashes' anymore. Then there's the embalming fluid and other chemicals.

Crematoriums are strictly regulated and emit little smoke. There are actually two burners: one for the coffin and one to burn off all the smoke, gas and CO2 released from the coffin, which is then dispersed.