An article published in The Conversation warns that five familiar foods could cost more this winter: chocolate, potatoes, leafy greens, bread and olive oil. They seem an odd assortment. Together, however, they show how weather, energy and long supply chains affect what we can afford to eat.

Chocolate and olive oil depend largely on harvests abroad. Potatoes, greens and wheat can be grown much closer to home, yet they too depend on suitable weather, fuel, machinery and reliable water supplies. A poor harvest is only one part of the cost. Food must also be stored, processed, transported and sold.

The UK wheat harvest illustrates the problem. The Agriculture and Horticulture Development Board reported in August that wheat yields were around 12% below the five-year average after prolonged dry weather. Yet the price of a loaf cannot be explained by the wheat harvest alone. Milling, baking and distribution all require energy.

For households, the distinction matters little when the weekly bill rises. Potatoes and bread are ordinary, filling foods. If they become dearer, families cannot simply stop buying food. Some will change what they eat; others will cut back elsewhere. The pressure is greatest on people who already have little spare money.

What might localism offer? It cannot make cocoa grow in Herefordshire or protect every crop from drought. Nor can a locality produce everything it needs. But it can strengthen the parts of food supply over which people have some practical influence: local growers, suitable crops, food storage, small mills and bakeries, and direct links between producers and customers.

That means paying attention to water and soil as well as to prices. A locality that loses its growers, growing land and food skills cannot quickly recover them when distant supplies become expensive. Keeping those capacities alive may appear costly in an ordinary year, but their value becomes clearer when harvests fail or transport costs rise.

The five foods in The Conversation are a reminder that cheap food has depended on favourable conditions at many points along the way. We should expect those conditions to vary. Localism offers a way to become more capable where we live, while continuing to trade for what cannot sensibly be produced here. The aim is a dependable supply of good food at a price people can afford