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Agricultural Biodiversity Weblog
There’s a fascinating paper in last week’s Science Express from a heavyweight bunch of scientists and advisers in the UK, on “the challenge of feeding 9 billion people”. It makes some seriously interesting points, raising lots of questions (and far fewer answers, natch). And being as it is both very tightly written and behind a paywall, I’m just going to quote from it at length. And comment.
After reviewing the main challenges — land, water, mouths, climate — the authors set out their stall.
So how can more food be produced sustainably? In the past, the primary solution to food shortages has been to bring more land into agriculture and to exploit new fish stocks. Yet over the last five decades, while grain production has more than doubled, the amount of land devoted to arable agriculture globally has increased by only about 9% (14). Some new land could be brought into cultivation but the competition for land from other human activities makes this an increasingly unlikely or costly solution, particularly if protecting biodiversity and the public goods provided by natural ecosystems (for example carbon storage in rainforest) are given higher priority (15). Formerly productive agricultural land has in recent decades been lost to urbanization and other human uses, as well as to desertification, salinization, soil erosion and other consequences of unsustainable land management (16). Further losses, which may be exacerbated by climate change, are likely (7).
They consider five sets of options: Closing the yield gap, increasing production limits, reducing waste, changing diets and expanding agriculture. Most important first …
The yield gap is the difference between what farmers achieve with the best genetic material, inputs and management and the average under particular circumstances, and it has become common to claim that bringing all farmers up to snuff would solve the world’s food security woes. Godfray et al. avoid that pitfall, and have a neat way of illustrating the yield gap, with changes in per capita food production over the past 50 years.
In Asia this has increased approximately twofold (in China …