Feeding the World in 2050 – Can We Do It?
DR. DENNIS B. EGLI
LEXINGTON, KENTUCKY
Recently I came across the statement that feeding the world’s population in 2050 would require 50 to 100% increases in yield. I have seen these figures before and wondered if they are valid. Afterall, 2050 is only 26 years from now. Doubling crop yields in roughly a quarter of a century seems like a huge challenge.
What does the historical record tell us about yield growth? Yields of two major food crops -wheat (world) and rice (Asia) - were up by approximately 30% over the last 25 years. Obviously, the rate of yield growth will have to increase a lot to meet the 50 to 100% goal.
Is such a large increase in production needed? The answer to this question hinges, in part, on changes in population and diet. Population growth rates are declining, with 66 countries in the world reporting growth rates below replacement. China just announced that its population is declining. The demand for food, fueled by population growth, is not increasing as fast as it once was.
Changes in diet are also an important part of the equation. Eating more meat, often associated with rising prosperity, requires more feed (grain) production per capita compared with a plant-based diet.
Production of grain crops per capita (kg of grain per person) provides a simple comparison of changes in population and agricultural production. Production per capita of wheat (World) and rice (Asia) increased steadily from 1961 through roughly 1985, clearly illustrating the power of the Green Revolution (Fig. 1). The increase in production (mostly from increasing yield) after 1985 matched the increase in population through 2018, so the production per capita did not change (ignoring the year-to-year fluctuations). Population increased by 61 (World) and 64% (Asia) (3 and 2 billion people, respectively) during this period, but the production of wheat and rice matched the increase in population. Increasing yields after 1985 produced enough wheat and rice to feed the growing population.
We did ok in the past, but what about the future? Projections of production per capita into the future (dashed lines in Fig. 1) were based on two assumptions. First, I assumed that the harvested area of both crops did not change, and, secondly, I assumed that population would grow at the median rate estimated by the United Nations Population Group in 2019. I calculated future productivity using the average (2009 to 2018)(linear) yield growth rate.
Surprisingly, the average rate of yield growth resulted in increases in production per capita for both crops (Fig. 1) reflecting the declining rate of population growth. Production per capita was maintained when the yield growth rate was reduced to one-half the average rate. Producing enough wheat and rice to feed the population in 2050 required yield growth that was only half of the average rate from 2009 to 2018. One-half the recent rate results in a 28 (wheat) and 14% (rice) increase in yield by 2050 – substantially less than the 50 to 100% target commonly mentioned in the literature.
It is worth noting that assuming no yield growth resulted in declines in production per capita for both crops (Fig. 1). We must increase production to meet the future demand for wheat and rice, but the increase may not have to be as large as many people think.
Our projections, however, did not consider possible effects of climate change on future food production. Higher temperatures will probably reduce yield of grain crops, but we have a cushion if we only need one-half of the current rate of yield growth to maintain production per capita.
Climate change may also cause extended droughts and excess rainfall which could cause catastrophic reductions in yield or even force abandonment of some cropping areas (think about California in the past few years). The extent of these disasters will depend upon how quickly society can reduce greenhouse gas emissions.
The analysis presented here for two major food crops is much more optimistic about the future than the 50 to 100% folks. Maintaining yield growth at one-half of the recent rate seems much more doable than doubling yield. Our ace in the hole is the continuous development of new technologies that will help increase productivity and counter some of the effects of climate change. In this time of uncertainty, it is worthwhile to remember the words of Franklin Delano Roosevelt (32nd president of the United States) – “We observe a world of great opportunities disguised as insoluble problems”. ∆
DR. DENNIS B. EGLI: University of Kentucky