IN ALL the discussions about “building back greener” it is easy to overlook what is happening under our feet. Soil degradation is a far bigger threat to the planet than flying, and the main cause is industrial farming. Tilling soil without building it back with organic matter has led to an epic loss of carbon and ever more degraded soil.

Soil degrades exponentially: exposed to the sun and wind, it loses nutrients, sheds carbon, and the bacteria and insect life disappears. As the land dries up and compacts, it repels water, which carries off more top soil. So you need ever bigger machinery to break it up for sowing, and ever more chemical fertiliser to persuade food to grow in it. It’s a vicious, climate-changing cycle.