In an attempt to provide useful information comparing the two traditional options—traditional burial and traditional (flame) cremation—with the newer and more environmentally friendly options of alkaline hydrolysis, natural organic reduction, and green burial, a comparison of the various environmental considerations is described in this downloadable and printable PDF.
There is no firm data directly comparing these options. In any case, even within each category, exact processes, and therefore environmental impact, vary somewhat.
Some ways in which environmental impact can vary:
- Traditional burial: The amount of nonbiodegradable resources used depends on whether a vault or liner (which has no bottom) is used, whether a biodegradable casket is chosen, and whether there is traditional embalming, the use of newer, less toxic embalming materials, or no embalming at all.
- Traditional (flame) cremation: Most modern crematories have a secondary combustion chamber that further incinerates and removes almost all particulate matter (ash and visible smoke) from being discharged into the air but some residual toxic gases remain and a large volume of greenhouse gases is still released. The average amount of energy required has been estimated to be akin to driving 500 miles.
- Alkaline hydrolysis: The precise formula for the processing fluid varies, along with the amount of heat and pressure applied and the method of agitation. These factors affect the total amount of energy used.
- Natural organic reduction: Variations in the amount of external heat applied (if any), as well as the rotation of the reduction chamber, affect energy usage.
- Green burial: Although this is listed as having the least environmental impact, this is strictly only true if the grave is dug by hand, only a simple biodegradable shroud is used, and the land used is maintained as a natural preserve.
All that said, the latter three methods are much less disturbing to the environment than either traditional burial or flame cremation. The difference between alkaline hydrolysis and natural organic reduction is arguable.
Of note: When a body is donated to medical science, it is ultimately cremated in the traditional way. Although a very few medical institutions now employ alkaline hydrolysis (including the Mayo Clinic), neither the Maryland State Anatomy Board nor the medical schools accepting bodies in our area do so at this time.