ASK most people to list the causes of climate change, and you would expect to hear about oil companies, flights and cars. But, increasingly, we are realising that producing our food has massive environmental impacts. Farming is one of the main drivers of deforestation and global warming, among many other issues.

The flip side of this is that improving the way we farm can have massive environmental benefits. Boosting yields so that we can grow the same amount of food on half the land could save a forest, along with all the carbon that it stores.

One of the best …