With a few digitally driven exceptions, the Covid-19 pandemic is clearly an ill wind that blows no one any good. Whatever country you turn to, whatever community you visit, the harm seems pervasive and often cruelly interlinked. Look at Guinea-Bissau in West Africa, one of the world’s poorest countries with a population of just 1.9 million. Around 86 per cent of its families rely on a single export crop – cashew nuts. Guinea-Bissau and a tiny handful of impoverished West African neighbours account for about 43 per cent of global exports. And as pubs and clubs across Europe have been shut by pandemic lockdowns , demand for snacks has crashed – and, with it, the earnings of a large part of Guinea-Bissau’s population, as cashew prices fell 10 per cent. It feels a bit like Edward Lorenz’s “butterfly effect” but, in this instance, the absence of a beer-drinker’s bar snack in Peckham, South London, has wrought an economic typhoon through West Africa. The same crisis is being played out across the nut-producing world, whether it is almond growers in California, walnut farmers in China or pistachio producers in Iran. Take the family-run nut company GNS from Arlington in Texas, which has been left with thousands of tonnes of nuts on its hands after its two main customers – two leading US airlines – cancelled orders. Nut prices have fallen worldwide as the Covid-19 pandemic shut down our social lives. According to commodity data company Mintec, US almond prices have fallen by 40 per cent this year, with walnuts down 18 per cent. The nut crisis has been compounded by bumper crops worldwide, and a wide range of idiosyncratic local challenges. In some places, the lockdown has blocked the flow of seasonal migrant labourers who farmers rely on to pick the crops. In others, port and airport closures have disrupted trade. Pandemic-related curfews in West Africa have affected harvesting and drying. In India, the cancellation of huge numbers of weddings has hit the production of cashew-based confectionery normally given as gifts. Chinese nut imports were hit by countrywide curbs on Spring Festival festivities – the high point of the year for nut consumption. For the United States, by far the world’s leading tree-nut producer (a category that mainly excludes peanuts), problems have been compounded by the US-China trade war , in which China has slapped hefty 60 per cent tariffs on most nut exports in retaliation against Donald Trump’s tariff war. According to J. Warner, a Chicago-based nut broker, sales of US almonds to China are down 23 per cent this year, with walnuts down 62 per cent and pistachios down 38 per cent. The sheer diversity of the global nut industry has made the butterfly effect virtually inevitable. The US accounts for over 80 per cent of the global almond crop, according to the International Nut and Dried Fruit Council Foundation, while China accounts for the lion’s share of peanut and walnut production, most of which it consumes domestically. India may only account for 5 per cent of global nut production, but according to the foundation, it accounts for 94 per cent of cashews, which are used not just in desserts but also in curries. Turkey accounts for 73 per cent of global hazelnut production. And pistachios, the supply of which for centuries was mainly from the province of Kerman in Iran, are today dominated by the US, in part because of massive embargoes on Iranian exports after the 1979 Iran hostage crisis. While macadamias come mainly from Australia and South Africa, pecans are almost entirely produced and consumed in the US and Mexico; where else do you find pecan pie? China is reported to be by far the largest producer of pine nuts, consuming most of them domestically. Most confusing of all, Brazil nuts seem mainly to come not from Brazil but from Bolivia and Peru. Europeans are the world’s largest consumers of nuts, not just in bar snacks but also cakes and breakfast cereals, and increasingly fashionably in butters, oils and milks as the health-conscious middle classes reduce their consumption of dairy products. But their preferences focus mainly on almonds, walnuts and cashews. It is the Chinese who dominate demand for walnuts – which are believed to be linked with brain health – and for pistachios, whose Chinese name translates as “ happy nuts ” because of the smile created as their shells begin to open. Producers have for a decade or more been predicting strong growth in global demand for nuts and nut-based products, partly because rising affluence worldwide seems to equate with a lot more nut snacking, and partly because of the broadening shift away from meat and dairy products, and towards plant-based diets. The nutritional value of nuts is increasingly prized, even though too many nuts can apparently harm the kidneys. Pistachios are particularly popular: bemusingly, researchers have found that the time it takes to shell a pistachio, combined with the sight of a growing mountain of shells, results in pistachio eaters consuming almost half as many calories as consumers of other nuts. So, even though the Covid-19 pandemic has struck a heavy blow to the hugely diverse nut industry, traders are still putting on a brave face. The long-term health trend augurs well for the industry. All they need is for the pubs and bars to reopen, airlines to take to the air again, and the weddings and other social festivities to resume. To the struggling nut farmers in Guinea-Bissau, that must feel like very cold, very distant comfort. But of one thing they can be sure: the ale-quaffing barflies in Peckham will not be gone from their favourite pubs for longer than absolutely necessary, so the butterfly effect may bring help sooner than they think. David Dodwell researches and writes about global, regional and Hong Kong challenges from a Hong Kong point of view