The topic of Peak Oil was all the rage there for a while and, depending on whom you speak to, it’s either been reached or it hasn’t. Either way our collective eye seems to have moved on from this particular calamity.
Yet it seems that no sooner has one fallen off our radar than another one rears its head: this time the issue of Peak Food.
In a paper published today in the journal Nature Communications, US researchers have found evidence that many current models used to predict global cereal production are over-exaggerating future crop yields. Our ability to judge our Future Food, has major repercussions on our food security, our economy, our interactions with the wider works as well as our individual abilities to feed ourselves.
The report shows that 30% of the world’s main cereal crops, including rice and wheat, have potentially reached maximum crop yield. This means that as the world’s population keeps rising we are going to struggle to match our food production levels.
Previously the econometric models used to estimate production have base their results on compound rates of yield. To my understanding mean that, on average, the percentage rate of increase of production remains steady, ie. 1% increase annually. This in turn means that each year the actual increase in production is larger than the previous year because the base amount is growing with each annual increase. Just like the compound interest of a bank account.
Yet according to the new paper, historical trends for many of these crops do not support the idea of compound, ever accelerating growth, but rather support a linear model, where the production increases by a given amount every year, rather than by a given percentage.
What’s worst is that crops in several parts of the world have shown an abrupt plateau, or even decrease, in production in recent years. No matter which side of the bar graph you stand on, with an accelerating population and, AT BEST, a linear growth in crop production, our food base is failing to keep up with the demands.
At least for this 30% of our major cereal crops, the models upon which we base out decisions need to be changed. And the findings of the report also imply that the same dangerously optimistic modelling may also be in play for some of the other 70%.
The paper, published by researchers from the University of Nebraska-Lincoln, calculates that the stagnation of yield affects 33% of global rice and 27% of global wheat production.
The closing remarks are best left to the authors themselves:
“…our analysis suggests that projections of crop yield trajectories based on extension of historical trends of the past 5 decades should be viewed with caution because these past trends were driven by rapid adoption of green revolution technologies that were largely one-time innovations…Approaching that rely on compound rates of yield increase or constant linear rates with no upper limit to yield growth are not supported by the analysis of historical yield trends and current understanding of crop physiology, and are likely to overestimate future increases in crop yields by a long margin…”
For all the numbers and pretty pictures see the full paper here: http://dx.doi.org/10.1038/ncomms3918
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