I’ve given a lot of talks over the past couple years about the importance of increasing agricultural productivity. Often these discussions get couched in Malthusian terms related to the need to produce more food for a growing world population. This 2009 document from the United Nations Food and Agricultural Organization, for example, suggests agricultural production in developed countries needs to double by 2050 to meet the demands of expected population growth.
I’ve been in enough of these conversations at this point to know that a common retort is that we already produce more than enough food to feed today’s population. Isn’t this just an issue of distribution rather than supply? I’ve addressed this issue in previous posts. Here, I want to draw out an implication of productivity growth that is probably obvious to many academic economists, but perhaps not as widely appreciated as it should be.
In particular, when we talk about increasing productivity enabling us to “do more with less,” the focus is often on the “do more” part. That is, increase food production. But, one shouldn’t forget the “with less” part. In short, increasing productivity means producing more sustainably.
To illustrate, consider the figure below (this is what we economists call a production function).
The bottom, lighter blue curve shows the relationship between various inputs (land, water, fertilizer, labor, etc.) and output (or food production). The figure shows that we can produce more food by adding more inputs - more land, more water, etc. However, there are diminishing returns. The first few gallons of water (or rain showers) produce a lot of extra bushels, but the next few gallons have a smaller effect. In fact, if we get too much water (i.e., a flood, as some parts of the Midwest are currently experiencing), production can actually fall. Diminishing marginal productivity was at the heart of the Malthusian concern - if we keep adding more population (or workers) to a fixed amount of land, the extra amount of food that will be produced (and available per worker) will fall, and hunger will ensue.
How do we escape this “trap”? Scientific research, innovation, and entrepreneurship allow us to shift up to a higher curve, as shown by the darker blue curve in the above graph. For a given amount of inputs (labor or land), we might actually have more food per person (now and on into the future as long as we continue to innovate and shift the curve outward).
Let’s, say, however, that one already thinks we produce “too much.” We don’t want any more food. Ok. I’ve drawn the vertical dashed line in the above figure to show a constant amount of food production. But look where this line intersects with the production functions. The figure shows that higher productivity curve allows us to use fewer inputs (less land, less water, less fertilizer, fewer pesticides, etc.) to produce the same amount of food as compared to the original lower production function.
The point? Even if one believes the problem of production is “solved”, don’t still want to find innovative ways to increase productivity to reduce our use of scarce natural resources?
So, how has US agricultural productivity fared? Here is data from the USDA Economic Research Service.
The figure shows that agricultural output has grown by factor of about 2.7 (i.e., we’re producing about 170% more food) since 1948, while use of agricultural inputs, in aggregate, have grown very little and is essentially flat. The gap between the output line at the top and the input line on the bottom is the definition of productivity.
How will this graph look in 2050? Is it possible the trend lines for outputs and inputs can flip? That is, flat output and falling inputs? If total output stays relatively constant, but we can find ways to improve productivity, then total input use will fall. That would be a great sustainability story.