Some years ago, the peak oil proponent Colin Campbell suggested that the oil being used to do stuff in the world at the time was producing the same levels of output as 22 billion human slaves would have done in the past.
Digging holes for apple trees over this past week has given me a direct comparison of the two methods of getting work done.
First, Annette & I decided that it would be good to get a couple of apple trees planted at an arbour before we get going with the major 100 tree orchard later.
So here we are with the tools to do the job:
Crow bar, shovel and post hole shovel.
First stage of work completed, 1/2 an hour of Annette’s time with ho-mi and mattock to get the grass out of the way, now using crow bar to loosen the poor man’s concrete we laughingly refer to as “soil”.
One hour, fifteen minutes later:
The hole is half a metre deep, 350mm x 400mm – giving us 0.07m3 of material removed for our 1 3/4 hours of effort. This hole is less than half of the size actually desirable for planting the apple…
Now let’s go get a Toro digger from the local hire joint:
This time we get a decent sized hole – 450mm diameter x 1m deep – although we still need to use the post hole shovel to get the material removed from the hole (see Martin in the background) – for a total of 0.16m3 removed in six minutes of drilling and five minutes of using the post hole shovel.
Which gives us 68 minutes per m3 or ~25 hours per m3 with the two different methods – nearly 25 times the labour output for the petrol powered device (not including the fossil fuels that went into making the machine, auger, shovel, crow bar and the like).
No wonder we* like fossil fuels so much…
*we in the sense of “our species” as opposed to “Annette & me”