Sustainable agricultural practices are essential and every bit helps. However, ultimately this just delays crunch time and isn't a solution unless combined with other sustainable practices including low or zero population growth, sustainable development of low emissions energy, industry and transport.

If Mwinga's kids go on to aspire to the extravagantly wasteful lifestyles we in the industrialised West currently enjoy and imagine, unrealistically, to be our right, the likelihood that their improved fortunes is sustainable looks slim. More like joining a big party paid for with credit and somehow believing the repayments won't ever come due.