One of those little stories that does so much to warm the cockles of my cruel, cruel, heart. One of the big campaigns of encouragement over in the U.K. is currently that we should all compost our food and garden waste rather than sending it off to a landfill. The justification for this return to the technology of the medieval peasantry (with, no doubt, the follow on of long drop latrines and the use of corn cobs…as long as those aren’t GM of course) is that landfills produce methane. True, but then the wormeries used to do the composting also emit greenhouse gases:
This is because worms used in composting emit nitrous oxide – a greenhouse gas 296 times more powerful, molecule for molecule, than carbon dioxide.
Landfill sites produce methane which is 23 times more powerful a greenhouse gas than carbon dioxide.
No, this does not mean that composting is ten times worse: it’s the more powerful gas but there’s less of it. The researchers actually find that the emissions, when calculated to CO2 equivalence, are about the same for each method. So should we say that wormeries are “just as bad for the planet as landfill”?
Again, no. For landfills (and all modern ones in the U.K. do this, by law) collect the methane generated and use it to produce power (some 30 percent of U.K. renewables come from this source) the emissions from which are CO2. So, with landfill we get energy plus CO2, with wormeries we just get nitrous oxide: fun stuff at the dentists but not good for much else except warming the planet.
Given this conversion we actually end up with the score sheet stating that wormeries are 23 times worse for the planet than landfills.
Yes, of course I find this amusing, all those wearing knitted tofu tops earnestly stirring their food slops, producing the very result they fear as they do so.
But there’s a more important point as well: unless you do a proper cost benefit analysis over the whole cycle, you’ll never find out what are the good things to do and what the bad. My major complaint with the whole Green Movement is that they never actually do this, perhaps they really ought to start?