Global heating and biodiversity loss are the first two of the three problems I have identified. These two are global systems and we know that humans, or, rather, some humans and some human cultures or social structures, are doing great damage. Agriculture, on the other hand, is a man-made system that arguably contributes to the other two. It's here for two reasons. First, even if we stop all CO2 pollution overnight, the world will continue to warm and we will loose land. We will need to re-think agriculture to mitigate some of the effects. Secondly, modern chemical agriculture has been extracting life from the soil to the extent that we have a mere 50 or 60 years worth of harvests in agricultural soils across the globe.¹ The timing is coincidence. I'm not suggesting that either global heating or biodiversity loss have contributed directly to this; it is simply that repeated application of machines and chemical fertilisers have reduced many soils to dust. The timing, though, is key, because we will desperately need properly working soils to help us through even the best scenario for the future. It would indeed be a waste of effort if we fixed global heating only to find the fertility has failed and we all died of starvation.

I've said that agriculture is a man-made system. It could also be seen as a collection of technical fixes laid on top of a natural system designed to grow plants. The point, of course, is to increase productivity, but the end result is to obscure the original process. We still need the productivity, of course, but, because we are looking at a largely man-made system, we should have the knowledge and the ability to understand what aspects of the various processes need to change to recover land fertility.

As it happens, we have other reasons for addressing agriculture. Industrial agriculture is a significant contributor to both global heating and biodiversity loss and needs to be addressed. On the other hand, many of the alternatives modes of working can act as carbon sinks. These two thoughts combine to make agriculture a subject worth dealing with explicitly.