Updated: Jul 16
Abegão, J.L.R & Silva, L.F (2020)
Social Sciences Institute (ICS), University of Lisbon.
(Author's contacts at the end)
A century ago, the human population was estimated to be lower than two billion people. At present, it nears eight billion. Each and every one of these individuals requires at the very least, subsistence level consumption to survive, and more, if they ought to thrive. Such sustenance requirements inflict damage on the natural world as agriculture transmogrifies the environment, bushmeat hunting reduces the geographical range and puts species on the brink of extinction and overfishing depletes and homogenizes life on the ocean and other water courses. Evidently, the impact from human existence goes beyond their dietary desiderata, however, a long list of environmental repercussions are linked to nourishment preconditions alone. This paper aims to shed light on the link between rising human numbers and the environmental impact from their sustenance, as well as providing pathways and approaches to reduce and hamper damage to the natural world.
Keywords: Population Growth; Overpopulation; Food Insecurity; Land-Use Changes; Climate Change
Humanity is going through an unparalleled demographic change. Our collective moved from 2 billion in the late 1920s to an expected 8 billion in the 2020s. Critically, even though the annual growth rate of the human population has been declining in the last half-century, from 2.1% in 1967 to 1.2% in 2017, the absolute number of people added every year - approximately 80 million individuals, from the 73 million back in 1967 - (Marsh, 2017) has only gone up. In effect, someone born a century ago has, in their lifetime, witnessed a quadrupling of the population (PRB, 2019; UNDESA, 2019).
The foreseen growth of the human population will be apportioned irregularly throughout the planet. The official forecasts (PRB, 2018) anticipate that of the 2.3 billion additional individuals between 2019 and 2050, roughly 1.3 billion will be born in Africa, 0.7 in Asia and 0.3 in the rest of the world. It is to be expected that such an increase in the human population will produce not just enormous sociological problems, but also profound ecological deterioration and climatic disruption (Ripple et al. 2017).
To examine the link between population growth and food security it is indispensable that Malthus’ thesis (1798) is brought into the limelight. To point out, at the edge of the nineteenth century, Reverend Thomas Malthus pondered on the rationale that the world could be circumscribed by natural limits, and that humanity was not beyond their grasp. Malthus reasoned that with the continuous growth of the human population and the arithmetic nature of food production, human numbers would overtake the available food supply and people would reap the woes of famine, disease and war (Malthus, 2007).
Assuredly, Malthus’s proposition hasn’t come to pass, even though that since when he wrote his Essay on the Principle of Population (1826) the human population has close to have multiplied by eight times. In effect, it can be argued that his premise did not yet materialize to its full extent because the natural world has gradually been converted to suit a human scheme of expansion.
In detail, the most fertile lands have been transformed into agricultural fields, specifically by ravaging forests, grasslands, wetlands and tropical forest and in the process, simplifying biodiversity dependent on those environs (IPBES, 2019); by confiscating considerable areas for animal pasture and grazing; by snatching a significant portion of the planet’s freshwater – only to be rechannelled for agriculture; by introducing massive quantities of synthetic chemicals and fertilizer pollutants (Stockholm Resilience Centre, 2015); and by seizing wildlife from the seas and forests. In other words, Malthus’s postulate of human adversity in the wake of continuous population growth has only been deferred due to the steady modification of the biosphere into a human-food factory, now known as the ‘Green Revolution’ (Crist, 2016).
It becomes important to realize that as the population rises and the biosphere is converted and degraded, food will become the new oil and land the new gold (Brown, 2012). To emphasize, on the demand side of the food equation, population growth, rise in per capita affluence, the transformation of food into biodiesel (Koh, 2007; Lapola et al. 2010) and the feeding of livestock are all together raising consumption and the rate of conversion of the Earth, while on the supply side, land degradation (European Commission, 2018), increasing water shortages (Goering, 2019), rising temperatures, extreme events and unpredictable rainfall patterns make it more challenging to keep increasing production (Brown, 2012).
To this end, food security - preserving supply and assuring equitable access to food - is a dominant consideration in terms of the chain reactions prompted by climatic changes and ecological degradation since these impinge on the most basic human rights, and are a driving force behind the uprooting of peoples. A hotter and more unstable climate will have pervasive, large-scale negative repercussions on food production and food security. Moreover, with an expanding human population and rising global demand for food, guaranteeing that the right food - especially staples such as wheat, maize and rice - can be yielded or supplied in the right places, at the right time and at the right price, becomes an integral challenge (Environmental Justice Foundation, 2017).
State of the World
The United Nations Food and Agriculture Organization predicted that about 815 million people of the 7.6 billion people in the world in 2016, or 10.7 percent, were subjected to chronic undernourishment in 2016. Almost all the hungry people, 780 million, lived in developing nations, representing 13.5 percent, or one in eight, of the population of developing countries (World Hunger.org, 2018). Continuing that trend, The State of Food Security and Nutrition in the World (2019) confirmed that an approximate 820 million people were under the same condition in 2018, casting doubt on the pace of progress of the SDGs, since the number of hungry people has, instead of decreasing, been steadily rising (Population Matters, 2019).
Nonetheless, the phenomenon appears to be mostly confined to zones affected by severe climate change or/and military conflicts (Coelho & Rodrigues, 2018). With this in mind, it is also argued that unrestrained population growth is leading to greater food insecurity (Population Matters, 2019). When vulnerable and volatile regions become centre stage for continuous growth of their populations, the end result can only be instability and Malthusian constraints (Baro & Deubel, 2006; Faisal & Parveen, 2004). This is especially true in the African continent, seeing that the region is expected to be the only to have its population grow until the end of the century, from its current 1.3 billion to 4.3 billion in 2100 (Cilluffo & Ruiz, 2019). In detail, Sub-Saharan Africa alone will be responsible for 28% of all increase from 2020 to 2050 (PRB, 2019) and triple its population by 2100 (Cilluffo & Ruiz, 2019). Starvation and famine on a large scale are well within conceivable expectations (Marsh, 2017; Linden, 2017).
Future trends estimate that by 2030, climate risks could place 43 million Africans below the poverty line (The World Bank, 2017) once fertile land is no longer arable, when sand replaces trees, when droughts take hold more often and endure for longer, when grass on which to graze domestics diminishes, and when hotter weather and shorter rains means growing food or tending to animals is no longer a viable option (Global Environment Facility, 2017). Moreover, a study published in Science (Chaplin-Kramer et al. 2019) asserts that as many as five billion people, particularly in Africa and South Asia, are more likely than not to face food and water shortages in the coming decades, as the deterioration of the natural world progresses.
Owing to the ecological consequences of food production having been extensively documented (Foley et al, 2005), the need to feed a growing human populace has led scientists to urge for production to be enlarged without impoverishing existing biodiversity and misusing additional natural areas for cultivation (Crist et al, 2017). Indeed, as a recent paper published in Nature argues, global agriculture is putting a heavy strain on planetary boundaries, and if these boundaries were to be strictly respected, roughly only 3.4 billion people could be fed presently (Gerten et al. 2020). Regardless, the scope of damage caused by our sustenance requirements is substantial, as is described in the World Atlas of Desertification from the Joint Research Centre at the European Commission (2018):
“Over the last 20 years the extent of land area harvested for crops has increased by 16 percent, the area under irrigation has doubled, and agricultural production has grown nearly threefold. As the world’s economy grows - however unevenly - there is a corresponding acceleration in the demand for animal protein. Intensification of the livestock sector to feedlots means more agriculture land is used to indirectly produce food.”
For this reason, it is necessary to be mindful that the current human population of 7.7 billion, is not just growing in size but also in per capita affluence. The concomitant effect from Population and Affluence was first described by Holdren & Ehrlich (1971) in their ‘I=PAT’ formula. Today, the impact of rising affluence is well described, as economies grow, citizens consume more and higher in the food chain. For one thing, it is estimated that as of 2016, half of the world was considered to be middle-class, and that at least until 2021, 160 million individuals on average would enter this class every year (Wang, 2018). It goes without saying that a growing population with more wealthy individuals creates more problems for the planet (Powell, 2013; Foley, 2014; Leaver, 2011; Myers & Kent, 2003) as our present needs are already considered widely unsustainable, as we are in a state of ecological overshoot (Global Footprint Network, 2019; Cairns, 2005).
Considering further growth alone will create enormous challenges, as remarked by the Food and Agricultural Organization of the United Nations (FAO). In 2009, when the report Global agriculture towards 2050 was released (FAO, 2009), projections for the human population in 2050 were setting the number to reach 9.1 billion. Ten years after the fact, present projections correct that estimation to 9.8 to 9.9 billion (PRB, 2019). If nothing else, this reveals how hard it is to predict the future, but also how the growth of the human population has been overly underestimated, and it might continue to be so (Pison, 2017). On the other hand, it also calls for an analysis of future food requirements with significant more demand and degree of austerity. To enumerate, FAO’s report already mentioned that:
“Feeding a world population of 9.1 billion people in 2050 would require raising overall food production by some 70 percent between 2005/07 and 2050. Production in the developing countries would need to almost double. This implies significant increases in the production of several key commodities. Annual cereal production, for instance, would have to grow by almost one billion tonnes, meat production by over 200 million tonnes to a total of 470 million tonnes in 2050, 72 percent of which in the developing countries, up from the 58 percent today […] arable land would expand by some 70 million ha […] land equipped for irrigation would expand by some 32 million ha, water withdrawals for irrigation would increase by almost 11 percent.”
Additionally, as it currently stands, roughly 3.2 billion people around the world depend on fish for nearly 20 percent of their animal protein. That translates into more than 150 million metric tons of fish every year being excised from the ocean (Gaworecki, 2018), with FAO (2019) asserting that “since 1961 the annual global growth in fish consumption has been twice as high as population growth.” The unintended consequence of a growing appetite as well as more people requesting fish protein is what the SOFIA Report from FAO (2018) describes as:
“The state of marine fishery resources, based on FAO’s monitoring of assessed marine fish stocks, has continued to decline. The fraction of marine fish stocks fished within biologically sustainable levels has exhibited a decreasing trend, from 90.0 percent in 1974 to 66.9 percent in 2015. In contrast, the percentage of stocks fished at biologically unsustainable levels increased from 10 percent in 1974 to 33.1 percent in 2015, with the largest increases in the late 1970s and 1980s.”
Besides this phenomenon of “Malthusian Overfishing” (Pauly, 1990), is the simultaneous increase in the consumption of meat and dairy products around the world (Bittman, 2008). Animal products presently comprise about 21 percent of the weight of food in global human diets - a 24 percent increase since 1960. However, a disproportion among developed and developing countries remains, even though consumption is on the rise as people become more prosperous (Myers & Kent, 2003).
Many developed countries have persistently maintained high animal product consumption rates constituting 40 percent or more of diets by mass (Machovina et al, 2015). This diverges from the majority of sub-Saharan countries and most of Southeast Asia which have maintained low animal product consumption rates (< 10 percent). Despite this, and of significant concern is the inflated animal consumption rates found in several countries throughout Asia, Africa and South America - most notably China which quadrupled its animal product consumption from 5 to 20 percent of diets since the 1960s (Bonhommeau et al, 2013). On the other hand, a point often overlooked is that as people improve their wealth, they consume more animal products. For instance, in Kenya, a piece of meat is one of the first things people treat themselves to when they get a little extra cash, and as the nation’s economy grows, so does the taste for beef. Cows have regularly been a traditional form of wealth; now they’re big business. In the past 15 years, the number of cows in Kenya has surged by more than 60 percent to around 20 million, driving – sometimes violent (Burke, 2017) - disputes for grazing lands (Gettleman, 2017).
Generally speaking, since the 1950s, global meat consumption has grown fivefold (Nierenberg et al, 2005). In the last twenty years alone, meat consumption in the developing world has doubled. Likewise, meat and dairy production is foreseen to double again by 2050 (FAO, 2006). It is crucial to remember what Machovina and colleagues (2015) signal:
“Though difficult to quantify, animal product consumption by humans (human carnivory) is likely the major driver of deforestation, pollution, climate change, overfishing, sedimentation of coastal areas, facilitation of invasions by alien species (FAO, 2006) and loss of wild carnivores (Ripple et al, 2014) and wild herbivores (Ripple et al, 2015).”
Specifically, if China incorporates the dietary habits akin to those of the average American citizens, each of its estimated 1.3 to 1.5 billion inhabitants would increase their consumption of meat and other animal-products by an average of 138 percent (Liu & Diamond, 2005; Bonhommeau et al, 2013). India, the world’s second most populous country – foreseen to become number one by 2023-24 - has also exhibited soaring animal product consumption with increasing affluence, but its rates of increase have been lower than China (Bonhommeau et al, 2013).
At present, China is consuming 28 percent of the world’s meat, including 50 percent of all pork. Nonetheless, China still drops behind a dozen other countries which have higher per capita meat consumption (Myers, 2015). In detail, the average American or Australian ingests up to twice as much meat per individual compared to Chinese citizens (Milman & Leavenworth, 2016).
Correspondingly, the swelling of the global consumer class, which has increased by hundreds of millions of people in the past two decades and will continue to surge by billions in the decades ahead (Ravallion, 2010; Kharas, 2017) will constitute, nothing less than an existential threat. A global middle class of 3.2 billion people in 2016 is envisioned to ascend to roughly 5 billion by 2030 (Kharas, 2017). Coupled with this seventy percent of India’s population is foreseen to enrol the ranks of the middle class by 2026, supplementing almost half a billion consumers to the global economy (up from 50 million in 2006) (Gupta, 2011). Equally important is Africa, which is predicted to reach between 3 billion and 6.1 billion people by 2100, from 1.2 billion people today (Engelman, 2016). Likewise, as the middle class in Africa, Asia, and Latin America continues to amplify - a reasonable expectation and policy orientation - the stress added to that of the developed world on the biosphere will become severe (Crist et al, 2017).
However, the size of the human population isn’t the only problem on the horizon, as “population is the multiplier of everything else” (Ryerson, 2010). For starters, increased calorie requirements based on increasing body weight and mass, could lead to a total demand increase of up to 80 percent more calories by 2100 (Depenbusch & Klasen, 2019). Even changes to diets, such as the consumption of less animal products or straight up vegetarianism and veganism, as welcome as they can be, will not stem ecological degradation in the face of rising numbers of consumers (Tree, 2018; Martindale, 2020). A similar case can be made for a transition for more organic methods, as that leads to an increment in greenhouse gas emissions (Smith, Kirk, Jones & Williams, 2019). On the other hand, the UN’s Intergovernmental Panel on Climate Change warns that the global food supply will face increasing turmoil from climatic change, and one of the consequences will be food prices becoming prohibitively expensive (Houser, 2019), on top of billions foreseen not to have access to the necessary fruit and vegetable to maintain a healthy diet, by 2050, a Lancet study affirms (Mason-D’Croz et al. 2019).
Evidently, reducing the intake of animal protein would bring enormous benefits (Ingraham, 2019), such as alleviating the water footprint demanded by livestock, since so many people already are under a situation of water-stress and the increasing demands of additional humans are seen as a looming crisis (Sengupta & Cai, 2019). Moreover, with the ‘water towers’ of the planet facing increasing threats from human claim and climate change, it is conceivable that up two billion people might face the collapse of these essential resources (Immerzeel et al. 2019, with the situation only seen as worsening with further growth of the human population (Schlosser et al. 2014; Goering, 2019).
Altogether, the eminent EAT-Lancet Commission on Food, Planet, Health report concludes that a profound transformation in diet, food production and reduction of waste could allow a global human population of 10 billion (forecasts for 2050) to be fed without causing irreversible damage to the Earth’s biosphere. Crucially, the report cautions that beyond 10 billion humans, malnutrition and environmental repercussions on a large scale are increasingly likely (Willett et al. 2019).
A similar message is echoed by another study (Berners-Lee, Kennelly, Watson & Hewitt, 2019), which argues that radical changes to the dietary choices and current food production could provide for the needs of roughly 10 billion people. The next section explores approaches and pathways for a cultivated planet (Foley et al. 2011).
What Approaches contribute to feeding nearly 10 billion people by 2050?
Solutions aimed at strengthening food security at different scales have become increasingly challenging for experts in the field, considering future scenarios of the impacts of population growth from a perspective of climate change, disasters, migration and land use changes.
There is a clear need for transformative change in the land management and food production sectors to address the global land challenges of climate change mitigation, climate change adaptation, combatting land degradation and desertification, and delivering food security (Smith et al. 2019). Food systems are often characterised by lack of knowledge and data and have high levels of complexity that are not sufficiently accommodated for in current financial, economic, political, legal and social structures and processes (Ingram et al. 2020).
Under a social vulnerability perspective, increases in corporate power (food production sector), the climate crisis and unfair access to natural resources, impact on people’s ability to grow and buy food, reflecting the rampant economic and gender inequality. At one end, the people who produce our food, and more so women, often face the greatest levels of hunger, get paid less than men and work under degrading conditions (OXFAM, 2020). In the same way, the degree of vulnerability of the populations exposed to climate related hazards, its resilience to the shocks, and the capacity to cope with the changing conditions, also determines the heterogeneity of the response to climate induced stressors on the human environment (Migali et at. 2018).
In a report about international migration drivers (OXFAM, 2020), the authors demonstrate how the slow onset of events linked with increasing temperature, reduced precipitation, drought events, and land degradation were found to be relevant in determining migration flows out of rural areas, especially in the least developed countries. Fast-onset climate related events such as floods are found to affect communities by forcing them to relocate temporarily in the surrounding regions. The main features of the climate induced migrations are therefore their short distance and short duration. At the same time, climate factors are likely to impact on the conditions favouring the decision towards long term and long-distance migration.
Many rural areas are experiencing large-scale outmigration of young people and increases in the inflow of remittances (FAO, 2019). Recent World Bank Studies finds that El Niño produces losses in GDP, consumption, and income for all households, in all countries, regardless of income level, urban-rural location, or gender. According to the estimations, national GDP losses from El Niño range from just $21 million per event in Lao PDR to $3.3 billion in the Philippines. Consequently, El Niño threatens the region’s poverty reduction and food security is hightened compared with the past decade. During a strong El Niño, simulations in the reports estimate that 5.1 million more people will fall into poverty In the Philippines, and 1.7 million more in Vietnam, in one of the most unspoken climate risks in East Asia and the Pacific (Sutton & Weng, 2019).
Climate change affects biodiversity for food and agriculture and ecosystem services both directly and indirectly increasing the vulnerability of agricultural sector to environmental risks. A study of post-disaster needs assessments covering 74 medium- to large-scale disasters in 53 developing countries between 2006 and 2016 showed that agriculture accounted for 23 percent of all losses and damage incurred (FAO, 2018e), where droughts are concerned, agriculture absorbed 83 percent of the economic impact. Overall, the crop sector was the most affected (49 percent of all damage and losses), followed by the livestock sector (36 percent). The most damaging types of disaster in the crop sector were floods, in the livestock sector it was droughts, in the forest sector storms, and in fisheries floods and storms (FAO, 2019).
Because of feedback effects, addressing food supply, development and poverty reduction, and environmental protection in isolation would probably undermine the chances of meeting all three (Searchinger et al. 2019). The authors evaluate for example, that the world could focus on raising food production by converting forests and savannas to croplands and grazing lands, but this approach would increase agriculture related GHG emissions from the loss of carbon in plants and soils. The climate effects of such an approach would likely have large adverse effects on agricultural output due to higher average temperatures, extended heat waves, flooding, shifting precipitation patterns, and saltwater inundation or intrusion of coastal fields.
Alternatives that combat the effect of climate change and population growth on food systems have addressed different strategies ranging from developing market policies, scaling back food production and distribution, resilient agriculture, sustainable forest use, and land use management. An World Resources Report proposes a menu of options that could allow the world to achieve a sustainable food future by meeting growing demands for food, avoiding deforestation, and reforesting or restoring abandoned and unproductive land—and in ways that help stabilize the climate, promote economic development, and reduce poverty.
Achieving these goals requires closing three great “gaps” by 2050, as (i) the food gap (ii) the land gap (iii) the GHG mitigation gap. This report considered a 22-item “menu for a sustainable food future,” which is divided into five “courses” that together could close these gaps: (1) reduce growth in demand for food and agricultural products; (2) increase food production without expanding agricultural land; (3) protect and restore natural ecosystems; (4) increase fish supply (through improved wild fisheries management and aquaculture); and (5) reduce GHG emissions from agricultural production (Searchinger et al. 2019).
In the same way Smith et al. (2019) evaluated the potential for 40 practices to address in the land management and food production sectors to address the global land challenges of climate change mitigation and adaptation. The authors concluded that nine options deliver medium to large benefits for all four land challenges. A further two options have no global estimates for adaptation but have medium to large benefits for all other land challenges. Five options have large mitigation potential (>3 Gt CO2eq/year) without adverse impacts on the other land challenges. Five options have moderate mitigation potential, with no adverse impacts on the other land challenges. Sixteen practices have large adaptation potential (>25 million people benefit), without adverse side effects on other land challenges.
The same authors evaluated that most practices can be applied without competing for available land. However, seven options could result in competition for land. A large number of practices do not require dedicated land, including several land management’s options, all value chain options, and all risk management options. Four options could greatly increase competition for land if applied at a large scale, though the impact is scale and context specific, highlighting the need for safeguards to ensure that expansion of land for mitigation does not impact natural systems and food security. A number of practices, such as increased food productivity, dietary change and reduced food loss and waste, can reduce demand for land conversion, thereby potentially freeing-up land and creating opportunities for enhanced implementation of other practices, making them important components of portfolios of practices to address the combined land challenges. This practice has been classified into land management, value chain management and risk management-based practices, respectively. All of these are summarized in the table below.
In a broad context, restoration of degraded ecosystems is an opportunity to mitigate climate change and combat food insecurity. However, integrating forest restoration with agricultural production is one of the major challenges for the political, economic and regulatory aspects. The United Nations Decade on Ecosystem Restoration (2021–2030) aims to accelerate the restoration of degraded ecosystems to boost climate stability, food security, water supply and the conservation of biodiversity. In this milieu, understanding ecosystem responses to disturbance events that are degrading the major ecosystems of the earth is crucial to advance their restoration (Álvarez-Yépiz et al. 2020).
An important strategy to consider regarding land use and food security is the scale of the solutions. Considering that most of the daily fed comes from smallholders farmers, solutions related to local productive arrangements, promotion of free markets, school feeding programs and political-economic subsidies such as Payment for Ecosystem Services (PES) are of fundamental importance for the diversification of production and income increase for small and medium rural owners.
Around 30% of the world's rural population use trees across 46% of all agricultural landscapes (Lasco at al. 2014), meaning that up to 2.3 billion people benefit from agroforestry, globally. In South America, for example, PES policies with farmers reconcile increased forest restoration, water and food security by encouraging the implementation of agroforestry systems as a strategic mechanism for watershed-scale management of water resources. Foley et al. (2011) showed that tremendous progress could be made by halting agricultural expansion, closing ‘yield gaps’ on underperforming lands, increasing cropping efficiency, shifting diets and reducing waste. Together, these strategies could double food production while greatly reducing the environmental impacts of agriculture.
All things considered, Springmann and colleagues (2018) encapsulate the currently accepted approaches to dealing with the challenges of feeding a growing population within environmental limits. They write:
“dietary changes towards healthier, more plant-based diets, improvements in technologies and management, and reductions in food loss and waste.”
Although these and many other authors understand the implications of the expected changes in population, the model followed for suggested options makes no mention of altering the size of the human population. Studies continue to mainly focus on technological and behavioural changes regarding diets and our relationship with waste, while completely sidestepping any meaningful discussion on population, reinforcing the perception that a population of roughly 10 billion in 2050 is already set in stone.
This silence regarding population is completely detrimental to any pragmatic and sober solution, as there are many conceivable approaches, which have been proven to work (Population Matters, 2020) such as family planning programs, removing barriers to contraception, safe and legal abortion services, education of boys and girls, challenging pro-natalistic cultures and religions and assumptions about family size as well as the alleviation of poverty. Alternatively, other approaches such as a global demographic policy (Morris, 2020), a market of reproductive rights (Lianos, 2017) or a proposal for a United Nations framework Convention on Population Growth (Harding, 2018) require immediate discussion and consideration.
Researchers dealing with the concomitant effects of population growth, food security and environmental degradation should be encouraged to assimilate these proposed approaches to mitigate some of the impending environmental damage and alleviate a portion of the misery and suffering awaiting our species and other living creatures inhabiting this planet.
However, political and economic solutions that address medium- and long-term strategic planning as a premise for integrated management of complex food systems, including sustainable land use practices, coupled with climate change adaptation strategies can be an important tool to reconcile population growth and the fight against hunger.
J.L.R. Abegão - firstname.lastname@example.org