Adelaide’s “Festival of Ideas” last month featured a useful discussion of the mining industry’s contribution to the economy, since replayed on the ABC program The National Interest.
Towards the end there was a brief discussion of how mining damages prime farming land. Asked an audience member: “How does farming start again on land that has been desecrated by lots of open-pit mines or coal gas seam mining?” Economics journalist Paul Cleary, now also a researcher at the ANU, responded by agreeing, calling it “heartbreaking” that some farmers had sold out to mining companies – “and they have sold out for three times the value because they’ve got huge debts, and it is heartbreaking to see those people leaving their land”.
I’m a fan of Cleary, who has a fine history of picking the right issues on which to go against the prevailing wisdom. And his comments drew warm applause from the audience.
But I found this whole line of inquiry puzzling. Yes, mining causes environmental damage. Yes, it can cause severe damage, notably when mine waste interacts with naturally-occurring water. Yes, coal-seam gas poses a bunch of special risks, and we need to find out whether its benefits are worth the potential damage. But overall, the scale of the damage that ensues from the typical mine seems relatively low compared with the scale of damage resulting from farming, for a given unit of GDP. (Note that I’m using relatively in its true sense, to imply a comparison rather than an absolute level.)
Farming’s great environmental impact is simple – habitat destruction. Forget climate change for a minute here: habitat destruction seems a more urgent problem. As ecologist Daniel Simberloff wrote a few years ago in American Scientist, “by far the major single cause of recent species extinction and current endangerment is habitat destruction”. Simberloff is a pioneer of sophisticated statistical approaches in ecology, famed for bringing a new mathematical rigour to the field. I could be wrong, but I think he understands the relative quantities and I don’t think his position is very controversial amongst ecologists.
And the simple reality is that farms take up a lot more space than mines for a given unit of output. I don’t have figures to hand, but the difference is fairly huge. Mining doesn’t destroy much habitat, because mines, even big mines, aren’t that big. Stand on the edge of the pit at Yallourn, say, and you can see a pretty big hole. But cast your eyes out to the horizon, and most of what you see is farmland cut out of the bush.
In short, mining seems to provide much greater economic benefits per unit of damage than farming. And awful though it sounds, in a world of massive habitat destruction, we need to think about how to get the biggest economic bang for the smallest environmental damage. So all other things being equal, environmentalists ought to prefer mining to farming.
And if a bunch of miners buy up farmland, my bet is that the economic value per unit of environmental damage rises sharply. On top of that, the farmers at least walk off their land with some money. Their debts wouldn’t be any less crippling if miners weren’t there to buy them out.
I’ve spent a lot more time on marginal farmland than I have on minesites, and I don’t know the literature as well as I’d like to. What am I missing here?