There's something mysterious afoot on the world's farms: For 50 years, the amount of food we're growing has steadily risen, and with it so has the amount of farmland used — until two decades ago, when food production started rising independently of new land. But how?
There are a couple different ways you can increase a farm's productivity. The most basic method is simply to throw more resources at the problem, although then there is always the problem of where to get those resources.
You can plant more land, but first you have to find it. You can plant more crops on the land you already have, but you have to double up on resources and labour. You can try to give your crops more water, but with the drought only intensifying, good luck getting it. Still, for a long time, those were largely the options available if you wanted to grow more food.
And then, something started to change.
Until 40 years ago, almost all agricultural growth was down to simply planting more and more. But, for farm growth today — while it's still a little about more plants, more water, more land — the real growth is in higher yield varieties, better and heartier plants, and more technologically-adept farm equipment.
Basically farms quit expanding to get bigger, and just got better at farming. Interestingly, the overall rate of growth of 2% every 10 years stayed remarkably constant with both methods across every decade — it's just the methodology that's changed.