It takes a lot of fire to burn a corpse. It takes a lot more to burn it
cleanly......eliminate ickly smells and reduce particulate emmissions. All
that burning produces a lot of carbon dioxide.....as well as consuming a
whole bunch of precious fossil fuel. Decompostion in the ground sequesters
a whole bunch of the carbon that is otherwise released via combustion. It
may not seem like a big deal where a single body is concerned, but think
big; six and a half billion human bodies is one hell of a carbon sink!
Moreover, humans are an easily an infinitely renewable resource......we can
always make more of them to capture and hold more carbon.

We have "partial" solution for this. http://en.wikipedia.org/wiki/Thermal_depolymerization
No, it doesn't hold the carbon, but rather makes use of it. I look at
it as a Soylent Green for our cars.
Frank Reid