Food Security and Land Use in the 21st Century: The Return of Malthus?

This piece will lay out the core of the problems human society will face – in the context of a century in which population pressures continue to mount and land constraints become ever more severe.

Population Pressures in the 21st Century

The 21st century will see a phenomenal amount of change in the global population. First, we are witnessing the continuation of a long-term process of human population growth, which commenced in earnest around 250 years ago (about the time of Malthus) and escalated thereafter, continuing to this day. A global population that was only about 1 billion individuals in 1750 escalated to about 2 billion individuals in 1950, and has since increased to approximately 7 billion. More importantly, the global population is expected to increase to about 11 billion individuals by the year 2100. This projection is based on the inherent momentum built into a population of the current size and demographic structure (i.e. age distribution). This would indeed amount to nearly the doubling of the human population over the course of the 21st century (from 6 to 11 billion). 

Resource Constraints and Population Pressures

The earth has never before experienced population pressures of this nature. The amount of land in use for agricultural production reached about 1.3 billion hectares in 1960, and has since expanded to nearer 1.6 billion hectares. Most analysts have suggested that the limit to arable land available is about 2 billion hectares, or a further 25% increase in land availability. 

Of course, placing all of the globally available arable land in service to agricultural production would not prove desirable. There are many other land uses that are required to sustain the planet and speak against further expansion of the total acreage devoted to agriculture. Biodiversity preservation is dependent upon land use allocations, as habitat conversion is one of the primary drivers of species loss. Also, carbon sequestration depends upon the retention of existing forests, and the expansion of these. In the coming century, with the onset of multiple global problems such as climate change in addition to food security, meeting food requirements from reduced land allocations proves crucial.

This table demonstrates the extent to which land has been allocated to agricultural production in recent years, and where these allocations have occurred. In line with population changes, the primary locations for further land use allocations are situated in developing countries, with sub-Saharan Africa being the main source of new agricultural lands. Conversely, in developed countries, the rate of growth of agricultural land use has already turned negative. This imbalance between developed and developing countries is an important reason to look deeper for the source of the future food security problems.

Agricultural Production, Research and Development, and Land Use

The fact that the developed world has had less reason to use land has been partly due to a slowing of population growth in that region. The most important contribution to this trend, however, has been the impact of research and development (R&D) in the agricultural sector. Agricultural R&D has been the primary contributor to the growth in yields on the production frontier over the past half-century. This has been true to the extent that land use has gone into decline in many developed countries while overall production has multiplied.Vast amounts of global land may be released from agricultural production, with relatively minor consequences for overall food production. 

In order to ascertain the extent to which this phenomenon (if replicated worldwide) is able to address the issue of food security, I, along with Ozgun Haznedar, Bruno Lanz and Pedro Naso, have estimated the global agricultural production function for the period 1960–2010, and then extrapolated from it to the globe for the remainder of this century. Our results are striking in that they indicate that vast amounts of global land may be released from agricultural production, with relatively minor consequences for overall food production.

This table demonstrates the relatively minor welfare losses that come from placing constraints on land use in agriculture (i.e., releasing land for other uses such as biodiversity and climate change). In essence, this shows that land is no longer the resource constraint that it once represented and that it is feasible to substitute R&D for land use to a large extent.

Changed Dependency Rates: The New Malthusianism? 

This brings us to the fundamental problem facing the 21st century, which (ironically) is the declining population growth rates that are accompanying the currently increasing levels of population. From the figure below it is possible to see that the population growth rate itself peaked in 1960 at 2.1% and has since plummeted to nearer 1% per annum. This rapid decline in population growth is accompanied by continuing increases in population levels because of (a) the rapid rise in population occurring between 1920 and 1960 (from 0.6% to 2.0%) and (b) the vastly increased level of population (from 2 billion to 7.5 billion) against which these rates are now applying. It is this recent history of rapid growth that provides the momentum for ongoing increases in population, despite momentous drops in the current growth rate.

And herein lies the problem of food security in the 21st century. It is the combination of high population levels and low growth rates that will effectively “invert” the population pyramid in coming decades, resulting in vastly increasing dependency rates in the global population. A “dependency rate” refers to the percentage of the population that is economically inactive while remaining nutritionally active. For the past half-century, this rate has remained remarkably stable at about 7% of the population (defined as those neither in the labour force nor in training). In the coming century, the dependency rate is expected to approach 30% on a global basis, and a much higher rate in individual countries of the developed world (see info box).

An inverted population pyramid implies a very large older population, unlikely to contribute to the R&D sector and reliant upon a reduced labour force. This means that the source of the solutions to the food security problems of previous decades is now significantly handicapped by the switch in the relative sizes of the labour force and its dependents. The dependency factor has increased by about four times on each unit of labour – which that reduced labour pool must now feed as well. So, the Malthusian dilemmas of the 18th century (and 19th and 20th) were successfully evaded by means of the application of younger pools of talent to this particular form of problem solving. The Malthusian dilemma of the 21st century is different because we are facing constraints of both natural and human capital, in the context of increasing food requirements.

Thomas Malthus

Where to Turn? The Need to Develop the Resources of the Developing World

Is there a solution to this problem of increasingly constrained resources (human and natural) in the context of increasing global populations? If there is, it lies in the immediate investment of global funds into the human capital of developing nations. It is only in these regions of the world that both resources will continue to increase – with both populations and arable lands increasing in certain parts, principally sub-Saharan Africa. The solution to the problems of the 21st century probably lies in replicating the experience of the developed world in the developing. If the developed world has been successful at substituting human capital (and resulting R&D) for natural capital in the recent past, then this is likely to be possible in the developing as well.The human capital in developing regions needs to be a crucial part of the solution to the food security problems of the 21st century. 

The nature of these investments may take many shapes: investments in developing world agricultural production; investments in the human capital of the developing world (by, perhaps, sending more individuals from that part of the world to work or learn in other parts); investments in the technologies and extension agencies of the developing world; and investments in the institutions of higher learning in the developing world.

This is of course a very partial list of potential solutions, but at their core lies the need to integrate the resources of developing and developed parts of the world. The human capital in developing regions needs to be a crucial part of the solution to the food security problems of the 21st century.