Burial-land space used (could be crop land), chemicals, marble headstone (strip mining)-no thanks.
Cremation-none of the above, but could be air pollution from the process (depending on owners/ equipment),
mercury pollution (from teeth fillings) and the energy it takes to fire up the burners.
I found this article (no date listed, so I don't know how old it is) but it sounds like natural burial is catching on.
(Either for the whole body or whatever is left after organ donation.)
Long article but interesting. There are several links in the article too to investigate. Here are a few excerpts:
"In the United Kingdom, a compelling new consumer movement is underway.
Natural burial grounds—where people are buried in biodegradable containers, without embalming fluid or synthetics,
and returned to the earth to compost into soil nutrients with a forest of trees marking the spot—
are springing up across this island nation.
Hundreds of sites are offering some form of natural interment have emerged in the UK, Australia, New Zealand,
the US and Canada, with other countries coming on fast.
Natural burial movements can now be found in China, Japan, Germany, and Africa.
(Our old, outdated methods)-
What else is buried along with these embalmed bodies every year?

More than 100 thousand tons of steel, 10 tons of copper and brass, 30 million board feet of hardwood timber,
uncounted tons of plastic, vinyl, and fiberglass, and 1.5 million tons of reinforced concrete accompany Americans to the afterlife.
According to the Federal Trade Commission, more than 2 million embalming procedures are performed in the U.S. each year, producing two and a half to three gallons of blood and excess embalming fluid per body.
That fluid, along with the organs and internal parts suctioned out of the corpse

during the process,
goes down the drain and into the water supply. (Should this thread be listed under water pollution?)
Cremation takes fuel—wood, gas, or electricity today—and fuel is often scarce in times of disaster or,
as in our time, an unwise choice given the devastating effects of global climate change. (Burning coal one last time-

)
What’s Buried U.S. Cemeteries Every Year (And these are for the US-it doesn't include worldwide stats.)
827,060 gallons of embalming fluid
90,272 tons of steel (caskets)
2,700 tons of copper and bronze (caskets)
1,636,000 tons of reinforced concrete (vaults)
14,000 tons of steel (vaults)
30-plus million board feet of hardwoods (much tropical; caskets)"
http://www.beatree.com/