It is not difficult to see why there may be Christian objections to cremation. “The resurrection of the body” is a basic credal belief, founded on the Gospel accounts of the physical reality of Jesus’s resurrection. If you burn the body to a bucketful of dust, how can it possibly be resurrected? No surprise to find then that although cremation as a means of disposal of the dead is very ancient and widespread (both geographically and culturally) the Christian church found the idea repugnant, when, in the second half of the nineteenth century, the modern technology of cremation was perfected. Indeed, the matter was made more complicated by the fact that the first “modern” cremation in the UK was a deliberate act of defiance and disavowal of the doctrine of resurrection by a Welsh atheist in Llantrisant.
Soon, denominational loyalties opened a split between, broadly, fundamentalist and Pentecostal groups who continued to resist cremation (except in extraordinary situations such as war, famine or plague.) on the one hand; and the (slightly) more liberal theologians of the Roman Catholic and Anglican traditions on the other. They held that God can reconstitute any body - whether from ash or from soil - and endow it with the essential characteristics of the original so that it becomes as recognisable as it was in its earthly form.
It was not until 1964 that this view became official Roman Catholic doctrine - and it was even then treated with considerable caution, not to say distaste. Both Roman Catholic and Anglican traditions make it clear that burial is the preferred mode of disposal in normal conditions. Roman Catholics do not encourage the scattering of ashes; formally Anglicans need a bishop’s permission, though our experience is that this is widely ignored. The emphasis is on dignity and reverence as marks of respect for the body and personhood of the deceased.
Pentecostals and less biblically based groups like the Mormons would emphasise these, too; but would insist that the only way of securing them is by burial. Mormons have, however, recently become more tolerant of cremation, recognising that we depend on the grace and power of God to reconstitute us in our eternal state, whether we are buried, blown up or burnt to death in a house fire.
Faith communities are often slow to respond to social and technical changes in the world around them - and here is a classic case of that lagged response. It was 88 years that elapsed between the opening of the first crematorium in UK and a Catholic priest being permitted to officiate at a funeral there. All the evidence suggests that the old distaste of cremation will disappear as we become increasingly short of land for cemeteries. The environmental impact of cremation is becoming a (minor) concern; technical adaptations (eg “scrubbing” the flue gases) are mandated increasingly widely.