Mexico City — The world is not increasing yields of major crops quickly enough to meet future food demands from an expanding population, presenting a "looming and growing agricultural crisis", according to a study.
Yields of maize, rice, wheat and soybean - responsible for providing 43 per cent of global dietary energy and 40 per cent of protein - must increase between 60 and 110 per cent by 2050 to satisfy projected food consumption.
But yields will increase only by between 38 and 67 per cent at the current pace of improvement in yields, according to research published in PLOS ONE last month (19 June).
This will not meet demand, particularly from a growing population keen on meat and dairy products that must also share its agricultural land with biofuels, says the study by Deepak Ray and colleagues from the Institute on the Environment at the University of Minnesota, United States.
The study mapped agricultural statistics around the world and tracked how yields are changing in each country.
The findings are valuable because they look at specific regions and countries, says Hans Braun, director of the Global Wheat Program at the International Maize and Wheat Improvement Centre (CIMMYT) in Mexico.
"It confirms now on a regional basis what has been said by CIMMYT and many others: that if investment in agricultural research is not increased significantly, it is very likely that the world will experience major famine in the coming decades," he tells SciDev.Net.
Countries with the most severe problems, says Ray, are those where the production of crucial food crops is decreasing as the population increases. "This will then rapidly reduce the per capita production," he says.
Maize in Guatemala is one such example. It provides 36 per cent of dietary energy but yields are reducing even as the population is projected to increase in coming years.
Similarly, the top three rice-producing nations, China, India and Indonesia, are witnessing little growth in yields. When the growth in their populations is taken into account, production remains unchanged in China and India and drops dramatically in Indonesia.
"In numerous smaller rice producers across the world where rice is an important provider of daily dietary energy, such as in Peru, Ecuador, Bolivia, Benin, Togo, Myanmar, the Philippines, Malaysia, South Korea, Nepal and Sri Lanka, the per capita production may also remain unchanged," says the study.
The situation is similar for wheat, with many countries such as Afghanistan, Bolivia, Iraq, Paraguay and Peru seeing yield increases that are too small to maintain their current per capita harvests.
Unless changes are made, the outlook for developing countries in Africa and Latin America that already suffer food insecurity will not improve, the authors warn.
These changes include the boosting of crop yields by spreading best management practices and closing yield gaps across the globe, as well as clearing more land for agriculture, but also reducing food waste and eating less meat.
But Braun says that in many regions, such as Latin America, "there is no alternative to increasing yield - simply because there is no more land available to expand production respectively; if land is made arable it requires cutting trees.
"An obvious fact, but often ignored by policymakers, is that agricultural productivity can't be turned on and off like a factory, it requires long-term commitment," Braun says.
PLOS ONE: doi 10.1371/journal.pone.0066428 (2013)