Current increases in crop yields will not meet future food demand

ID-10062725 (2)Global food production must increase if we are to meet the rising demand for food, feed and fuel brought about by growing populations, incomes and western diets. It must increase in the face of severe natural resource constraints.  Current production growth, however, will not meet the world’s food needs, as a recent article by Ray et al, entitled Yield Trends Are Insufficient to Double Global Crop Production by 2050, attests.

To achieve food security we need to increase food production between 50 and 100% by 2050. Ray et al, however find that for four key global crops, maize, rice, wheat, and soybean, which currently produce nearly two-thirds of global agricultural calories, yield increases between 1961 and 2008 were only 1.6%, 1.0%, 0.9%, and 1.3% per year. To put this in perspective, a 2.4% per year rate of yield gains is needed to double crop production by 2050.

This high level analysis masks a lot of geographic variation. For example, maize yields are improving in Ethiopia, Angola, South Africa, and Madagascar but decreasing in such countries as Morocco, Chad, Somalia, Kenya and Zambia. There is a similar diversity in yield changes for soybean, wheat and rice.

One answer is to expand the amount of land we grow crops on (extensify), a solution that would be disastrous for the environment, for carbon emissions and for biodiversity, for which habitat loss is the biggest threat. The other is to intensify, increase the yields from existing agricultural land. Often intensification is associated with large-scale high-input commercial agriculture, also detrimental to the natural resource base. The UN estimates that 80% of the required increase in food production between 2015 and 2030 will have to come from intensification. Additionally strategies to reduce food loss and waste, change consumer eating preferences and ensure the food system is more equitable could also have a large impact.

In another recent article in Science, Garnett et al discuss a new paradigm that is gaining traction, one outlined by the Montpellier Panel in their 2013 Report, Sustainable Intensification: A New Paradigm for African Agriculture. Sustainable intensification (SI), which aims to reconcile food production and environmental protection, has been much discussed on this blog and is receiving increasing attention from decision makers. Garnett et al outline the four premises underlying SI:

1)     The need to increase production

2)     The need to meet this increased production through higher yields rather than greater area

3)     Equal attention should be given to increasing agriculture’s environmental sustainability as to production

4)     SI is a goal rather than a prescribed set of measures.

A 2011 study by Tilman et al found moderate intensification in under-yielding nations to reduce land clearing by 0.8 billion hectares, greenhouse gas emissions by two gigatonnes per year and reduce global nitrogen use by around 25 million tonnes per year when compared to a mixture of intensification and land clearing.

As Garnett et al acknowledge though, food security is not an assumed outcome of SI. Rather, as the Montpellier Panel Report points out, food security also requires supportive institutions, markets and policies, or in other words an enabling environment.

Opportunities to sustainably intensify do exist. Africa has a quarter of the world’s arable land, but only generates 10% of global agricultural output. As Ray et al’ s paper concludes “Many studies illustrate that intensification can be unsustainable, but several notable projects in Africa and elsewhere have shown that sustainable intensification is possible and necessary to boost global crop production.”

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Comments

  1. Reblogged this on Science on the Land and commented:
    argylesock says… Here’s good thinking.

  2. Yet one more reason why I went vegan.

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