Global Challenges
Issue no. 6 | November 2019
Endangered Earth
Global Challenges
Issue no. 6 | November 2019
Endangered Earth | Article 2

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

Reading time: 6 min

The coming century raises many important problems regarding population, food requirements and land use. In many ways, the issue at hand reminds us of Malthus’s bleak predictions regarding the interlinkages between population growth and resource constraints. Nevertheless, the problems of the coming century are likely to be very different from those that the Reverend Malthus foresaw.

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 19602010, 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 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.

By Timothy Swanson
Professor of International Economics
The Graduate Institute, Geneva

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Work cited:
Naso Pedro, Ozgun Haznedar, Bruno Lanz, and Timothy Swanson. 2019. “Food Security and Global Public Good Provision: A Macroeconomic Approach to Land Use Policy”, working paper (forthcoming).

Info Box

UN Dependency Rate Forecasts

Source: World Population Forecast, United Nations (2015).

Info Box

Welfare losses due to constraints on land use in agriculture

Land Constraint202520352050
1.4 billion hectare–0.29%–0.25%–0.19%
1.2 billon hectare–0.73%–0.59–0.45%
1.0 billion hectare–1.59%–1.18%–0.88%

Naso, Haznedar, Lanz and Swanson (2019).

Info Box

Total arable land in use: data and projections

N. Alexandratos and J. Bruinsma, “World Agriculture towards 2030/2050: The 2012
Revision” (ESA Working Paper 12-03, FAO, Rome), 109, http://www.fao.org/3/a-ap106e.pdf

Land degradation | Key terms

What is soil?

Like many common words, the word soil has several meanings. In its traditional meaning, soil is the natural medium for the growth of plants. Soil has also been defined as a natural body consisting of layers (soil horizons) that are composed of weathered mineral materials, organic material, air and water. Soil is the end product of the combined influence of climate, topography and organisms (flora, fauna and human) on parent materials (original rocks and minerals) over time. As a result, soil differs from its parent material in texture, structure, consistency, color, chemical, biological and physical characteristics. Soil is an essential component of land and eco-systems, which both are broader concepts encompassing vegetation, water and climate in the case of land, and in addition to those three aspects, also social and economic considerations in the case of ecosystems.

The word soil is also known as dirt, waste or earth.

Soil erosion

Soil erosion is a common term that is often confused with soil degradation as a whole, but in fact refers only to absolute soil losses in terms of topsoil and nutrients. This is indeed the most visible effect of soil degradation, but it does not cover all of its aspects. Soil erosion is a natural process in mountainous areas, but is often made much worse by poor management practices.

Land degradation

Land degradation has a wider scope than both soil erosion and soil degradation in that it covers all negative changes in the capacity of the ecosystem to provide goods and services (including biological and water-related goods and services, and, in the vision of LADA – Land Degradation Assessment in Dryland – also land-related social and economic goods and services).


Desertification is another common term used for (a) land degradation in dryland areas and/or (b) the irreversible change of the land to such a state it can no longer be recovered for its original use.


Mitigation is intervention intended to reduce ongoing degradation. This comes in at a stage when degradation has already begun. The main aim is to halt further degradation and to start improving resources and their functions. Mitigation impacts tend to be noticeable in the short-to-medium term: this then provides a strong incentive for further efforts. The word mitigation is also sometimes used to describe the reductions of impacts of degradation.


Rehabilitation is required when the land is already degraded to such an extent that the original use is no longer possible and the land has become practically unproductive. Longer-term and often more costly investments are needed to show any impact.

Land degradation neutrality

Land degradation neutrality describes the state whereby the amount and quality of land resources, necessary to support ecosystem functions and services and enhance food security, remains stable or increases within specified temporal and spatial scales and ecosystems (source: UNCDD).

Land grabbing

The term grabbing was adopted because of the lack of transparency in the set-up of land deals, their dubious legitimacy vis-à-vis communities who until then used these areas, and the dispossession the latter suffered once the deals were implemented. Estimates vary from 20 to 45 million hectares transacted between 2005 and 2010; the most recent estimates are around 30 million hectares in 78 countries. Actually, the calculation of grabbed areas has proven extremely challenging. Information is rarely disclosed given the controversial nature and the lack of legitimacy of those deals. Moreover, land grabs include not only transnational large-scale ones but also a broad range of national and local medium- and small-size land acquisitions that are hard to quantify.

Source (except for “land degradation neutrality” and “land grabbing”: © FAO, “FAO Soils Portal”, accessed 8 November 2019, http://www.fao.org/soils-portal/about/all-definitions/en/.

Interview with Professor Anne Saab

The Graduate Institute, Geneva.

Interview with Professor Filipe Calvão

Graduate Institute, Geneva.

Entretien avec le professeur Jacques Grinevald

Breakdown of the Global, Ice-Free Land Surface (130 million km2)

Source: IPCC, Climate Change and Land (August 2019), 4.

Five maps of land degradation issues

  • Global soil organic carbon map (in tonnes per hectare)

    FAO and ITPS, GSOCmap (v1.5.0), provided under Creative Commons CC BY 4.0 licence.

  • Map of active metal and energy minerals mining sites

    Source: SNL Metals & Mining Database, 2017. Provided under Creative Commons CC BY 4.0 licence on this page of the World Atlas of Desertification.

  • Map of patterns of aridity

    Source: Global Precipitation Climatology Centre and potential evapotranspiration data from the Climate Research Unit of the University of East Anglia (CRUTSv3.20), WAD3-JRC, modified from Spinoni J. 2015 [AP]. Provided under Creative Commons CC BY 4.0 licence on this page of the World Atlas of Desertification.

  • Map of transnational land acquisitions

    Copyright: European Environment Agency (EEA).

  • Map of active fires in the world on 25 August 2019

    Source: EFFIS – Copernicus | [Ver. 2.3.3], © OpenStreetMap. Provided under Creative Commons CC BY 4.0 licence on this page of the Global Wildfire Information System.

  1. Global soil organic carbon map (in tonnes per hectare)
  2. Map of active metal and energy minerals mining sites
  3. Map of patterns of aridity
  4. Map of transnational land acquisitions
  5. Map of active fires in the world on 25 August 2019
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