While global crop yields rose rapidly in the early decades of the “green revolution”, productivity is now plateauing in many regions of the world. A 2012 meta-study found that in 24%-39% of areas growing maize, rice, wheat and soybean, yields either failed to improve, stagnated after initial gains, or collapsed.
Only slightly more than half of all global rice and wheat areas (57% and 56% respectively) are still experiencing yield increases. The areas where yields have stagnated include some of the wealthiest, most industrialised and most hi-tech production systems: more than one-third of the wheat crop in the US (mostly in the Great Plains) is affected, along with more than a third of the Argentine wheat crop, and harvests all across Europe.
Meanwhile, rice yields are plateauing in California and most European rice-growing areas. This trend is also evident in some 80% of rice crops in China and Indonesia – two of the world’s major rice producers. Worryingly, this may only be the tip of the iceberg.
The reason the productivity of industrial agriculture is now under threat is because it has been systematically degrading the human and natural capital on which it relies. Pests, viruses, fungi, bacteria and weeds are adapting to chemical pest management faster than ever: 210 species of herbicide-resistant weeds have been identified. Meanwhile, synthetic fertilisers are fast destroying the soil biota and its nutrient-recycling potential. This creates a dangerous treadmill effect: increasing resistance leads to increasing pesticide use, generating mounting costs for farmers and further environmental degradation. This in turn requires additional doses of nutrient application to keep squeezing productivity out of the soils.