Can World agriculture, fisheries, aquaculture and forestry sustain burgeoning populations without habitat destruction, deforestation or species/biodiversity loss?

In the late 18th century Thomas Malthus wrote ‘The power of the population is so superior to the power of the Earth to produce substance for man, that premature death must in some shape or other visit the human race.’ (Wolchover, 2011). In this essay Malthus predicted that man’s capacity to reproduce would ultimately be his downfall through overpopulation, resource depletion and mass famine. His essay was priesent, given the state of the planet today, but is still the elephant in the room as people do not like discussing population pressure due to religious and other beliefs. There are many examples of population crashes, such as mid America, the Incas and Easter Island. This latter example has often been used as an example of how resource depletion leads ultimately to a population crash. Polynesians settled on Easter Island around 1200AD and the fertile soil allowed the population to grow to around 20000. The expanding population used wood from the forests to make boats and transport their giant statues. The exposed soil then washed away and the population went into decline. When the Dutch arrived there in the 1700’s it was just a sandy grassland with around 3000 starving people left. Jared Diamond in his book ‘Collapse’ observed that the factors involved in societal collapse were climate change, hostile neighbours, loss of trading partners and environmental problems, where the root problem was largely attributable to overpopulation in relation to the carrying capacity of the environment. The collapse of the Mayan, Anasazi and Easter Islanders was rapid as ‘maximum population, resource consumption, and waste production leads to maximum environmental impact where impact outstrips resources’ (Wikipedia). Diamond also took examples from the collapse of societies from the Greenland Norse and the Polynesians of Pitcairn Island, to the collapse into genocide in Rwanda, which was partially due to overpopulation. The world’s first climate change war was Darfur, Sudan, where a dramatic change in rainfall and the advance of the Sahara forced the Muslims and Christians to compete for land and water resources (Guinness Book of Records).

To feed the world’s projected population of 9.2 billion by 2050, we will require the resources of two worlds to sustain it (Renton, 2009). Sustainability can be defined as meeting the needs of present generations without jeopardizing the needs of future generations. According to scientific advisor to the British government, John Beddington, ‘Food security represents a greater threat to mankind than climate change itself’. If these projections are good, and we know that our present population of 7.7 billion is growing exponentially (Worldometers), then this conundrum could be approached in various ways. Either the world population needs to level off or we need to produce more food or a combination of both. If only it were that easy. Population is a very controversial topic. China, aware of its growing population introduced a controversial one child policy in 1979. This policy was relaxed in 2015 because of its skewed demography towards an older population. Although this policy curtailed China’s population by an estimated 400 million, its population now stands at 1.4 billion (Worldometer). India has a similar population of 1.3 billion. Uganda has one of the fastest growing populations in the World. And people from emerging economies tend to eat more meat and aspire to drive a car, most of which are still polluting, in proportion to their income increase. The ‘American Dream’, where everyone wants to live in a big house in the suburbs, drive a big Cadillac, eat burgers and fast foods and fly to all corners of the world is clearly unsustainable and a bad iconic vision.

What controls populations naturally? The energy flow through a food web is where sunlight is transferred to energy via photosynthesis by plants and this energy is consumed by herbivores which are in turn eaten by predators. Efficiency is lost with every step, so predator numbers in a stable situation are always lower than prey numbers. Predator – prey populations often follow natural cycles, where prey populations are controlled by predation, so when predator populations fall, there is an associated rise in the prey population and visa versa (Biology on line). The snowshoe hare and lynx which preys on the hare is a classic example of this. The vast herds of zebra, wildebeest and Thompson gazelle on the East African savannah are ONLY maintained as they are not static, but move following the rain and growth of grass, a process which is called grazing succession. Static herds would quickly deplete the available resources. Similarly the prides of lions and cheetahs there depend on this seasonal migration (Sinclair & Norton-Griffiths, 1979). Static herds are exactly what we have with cattle ranching, which can rapidly degrade the grasslands in dry marginal areas such as sub-Saharan Africa and Australia. In the Yellowstone Park, grey wolves were shot out in the 1920’s and this was followed by an increase in the population of elk. This had a negative impact as the aspen and cotton woods there became overgrazed and died leading to erosion (Wikipedia). Wolves were re-introduced there in 1995 and as the elk population was stabilized, so the condition of the cotton wood, willow and aspens improved. Apex predators are thus important in controlling populations. However, man has no predators and as an omnivore and meat-eater is ecologically also an apex predator, so we now have an inverted food web where huge quantities of primary production (grass and grain) are used to produce secondary production (milk and meat) far less efficiently.

Natural phenomena like El Nino have cyclical effects in the ocean, through nutrient upwelling, as well as the adjacent land yielding natural feast or famine situations as the land’s carrying capacity varies with the wet and dry cycles. Introduced alien species like the cane toad and Japanese knotweed spread quickly in the absence of controlling natural competitors or predators. As hunter gatherers, the human population was relatively stable as it was part of the ecosystem, but with settlement and agriculture populations began to expand but were prevented from growing exponentially by natural disasters, famine, wars and disease. Disasters of biblical proportions include earthquakes, tsunamis, flooding, drought and plagues of insects eating crops, but now added to this are anthropogenic changes like sea level rise and climate change brought about by mankind’s activities. Examples of natural disasters affecting populations are many. The 1931 Yellow River flood, for example, claimed the lives of up to 4 million people. Earthquakes, tsunamis, hurricanes, typhoons, cyclones and erupting volcanoes have continually claimed lives through history (World worst natural disasters). The volcanic explosion of Thera (now Santorini) in Greece around 1600 BC wiped out the entire Minoan civilisation (Wikipedia). In Indonesia the explosion of Krakatoa in 1883, claimed around 36000 lives through the blast and subsequent tsunami (Live Science). Famines can also claim a significant human cost. Throughout history famines have resulted in millions of people dying in most parts of the world, Europe included (Wikipedia). In the late 1700’s 11 million people died in the Skull Famine in India, while four famines in the 1800’s claimed a massive 45 million lives (Wikipedia). Between 1845 and 1849 the Great Potato Famine in Ireland led to the loss of a million lives and the displacement of a further 2 million (Brittania). The Russian famine of 1921 claimed 5 million lives while the Bengal famine of 1943 killed 7 million (Listverse) The Vietnamese famine of 1945 killed 2 million people. The Under the Mao regime, the great Chinese famine between 1959 and 1961 led to an estimated 20 to 40 million people dying of starvation (Wikipedia). The famine in Ethiopia from 1983 to 1985 killed 1.2 million people and displaced a further 2.5 million (Wikipedia). The North Korean famine in the late 1990’s claimed up to 3.5 million lives (Wikipedia).

Wars can also excise huge chunks out of living populations. Fifteen million people died during the First World War (1918-1918). During World War 2, over 60 million people were killed, which constituted 3% of the world’s population at the time (Wikipedia). Genocide can be included under war, such as the Holocaust when 6 million Jews were killed. Other political crimes include over a million prisoners who died in Gulag camps in Siberia, Russia under Stalin’s rule (between 1 and 1.7 million people), or the killing fields of Cambodia under the Pol Pot regime (between 1.5 and 3 million people). Other genocides include the Rwandan conflict which claimed the lives of between 500000 and a million mainly Tutsi’s, the Angolan genocide of 1994 where around 800000 people were killed, the Matabele Massacres in Zimbabwe under Robert Mugabe where between 20 and 80 thousand people were massacred. In 1995 an estimated 100000 people died in the Bosnian genocide (

In terms of disease, historically diseases like the black plague claimed a vast number of lives. Between 1347 and 1351 an estimated 75 to 200 million people died in Asia and Europe (Wikipedia). In 1918, the Spanish pandemic claimed an estimated 50 to 100 million people worldwide and infected an estimated 500m (Unicef; Wikipedia). More recently the spread of bird flu (H5N1) was extremely worrying as it was thought that it had the potential to spread globally in a global pandemic (Wikipedia). When AIDS initially struck in central Africa in the 1980’s, people died in droves. AIDS has claimed the lives of 35.4 million people world-wide with a further 37 million living with HIV in 2017 (Avert, 2017). In 2006 there were 40m people living with HIV, of which 25m were in sub-Saharan Africa (WWF). In 2014 Ebola haemorrhagic fever spread quickly in West Africa with projected numbers of people getting it estimated at between 20 000 and a million (Wikipedia). Although it was contained, with only 11000 deaths, it probably had the potential to become pandemic, as was envisaged in the movie Outbreak. Other diseases with pandemic potential are SARS, tuberculosis, Rift Valley Fever, Marsburg virus, resistant Staphylococcus (MRSA) and Bolivian haemorrhagic fever (Future pandemics). Malaria still remains one of the world’s biggest diseases killing around a million people per annum, but around 3.2 billion, nearly half the world’s population, are at risk (fact/myth). Tuberculosis is now one of the world’s deadliest diseases, with a high infection rate leading to 1.8 million deaths in 2015 (CDC). Bird flu, swine flu, or other viruses are now feared as they can also mutate and jump hosts to man with devastating consequences. The founder of the Gaia hypothesis, James Lovelock, in which he suggested that mother Earth (Gaia) had the capacity to heal itself, has even changed his thinking on how this planet can self-regulate with his new book ‘The Vanishing Face of Gaia: a Final Warning’ in which he notes that the planet is too overpopulated to stop its own destruction by greenhouse gases and global warming (Lovelock, 2009). Sir David Attenborough has stated that ‘if we do not control our population, then the natural world will’, as there are too many people and not enough land (Furness, 2013). In 2016 the world famous physicist Prof Stephen Hawking stated that Mankind’s biggest problem was mankind itself, with world population, and its associated problems like pollution expanding exponentially (Inquisitr, 2016). Modern thinking is that there are around ten effective ways to control population, which include delayed marriages, better rural medical facilities, legislative action against child labour and slavery, incentives such as discounted education for a single child, education and awareness, empowering women, the eradication of poverty, cheap and available contraception and development (Layers Technology). Developed countries especially Japan and Italy are experiencing low population growth, with aging populations, but in developing countries, especially in sub-Saharan Africa, populations are mushrooming due to poverty, with a young demographic, and the factors listed above, but China, Oman and Lebanon have the highest population growth rate which is due to economic growth and probably refugees in the case of Lebanon (Worldatlas). People are also living longer so that this changing demographic means more resources are needed per capita.

Yet despite natural disasters, wars, famine and disease, the world population is still increasing exponentially due to widespread inoculations, advances in medical science and mechanised farming, but global pandemics are a worry. Mankind always bounces back so that education, social upliftment and the empowerment of women need to be addressed. There is a strong correlation between population control and women’s emancipation, with developed countries like Italy and Japan having negative population growth, while developing countries like Nigeria, China and India have burgeoning ones (Global Issues; NIP Global). The Bill Gates Foundation was initially set up to investigate population growth and it turned out that there was a correlation between poor health and high family sizes, and that where health, especially in women, was improved, the birth rate dropped (TED talks, Bill Gates). Kerala in southern India is an interesting case, as here there is a matriarchal line of inheritance, and, although poor, it has a very high literacy and education rate. There is a big state investment in social services here so health is good and this, linked to a good education, has led to a fall in the birth rate and low infant mortality, which is quite different to the rest of India (Wikipedia; Oxfam blogs). In Kerala, the most effective population control measure by far is Women Empowerment (Soapboxie, 2019). Kerala, it would seem, is a good model for the future.


It would seem that perhaps Malthus, Lovelock, Diamond, Hawking and Attenborough were right, the world’s population explosion is affecting the health of the planet and all the multiple species that it supports, man included. Have we the knowledge and collective political will to halt this downward spiral, or will it collapse, like Easter Island? The problem is that many people aspire towards the American dream, to have a big house and car (fossil fuel based) and chomp fast foods containing beef (MacDonalds/ Burger King) or chicken (KFC) from monocultures, which have high carbon footprints and bad ecological histories. However, with the Climate Emergency (Campaign Against Climate Change) wake-up call, we can make smarter choices in our lives, but in places like sub-Saharan Africa it is much harder to control. Is Kerala a ray of hope for the planet? As India and China are rapidly being drawn out of poverty, so their health and education will improve and with it, a fall in birth rate. Perhaps we won’t have a world population of 9.2 billion by 2050, but, our population growth rate along with our carbon emissions will have to reach zero. Perhaps new wars, famines or outbreak of a new pandemic disease will curb the planets population for a while. One thing is for sure; this planet can ONLY support a finite sustainable human population IF we have a healthy green planet for ecological servicing by absorbing our carbon emissions, and releasing oxygen to provide us with the diversity that is needed for our food, new products and drugs. But the current rate of deforestation in the Amazon, Indonesia and Africa, and the thawing of the permafrost in Canada and Siberia is making this target ever harder to achieve.


Avert, 2017.

BBC, 2015.

Biology on line.

CDC, Centre for Disease Control.

Diamond, J., 2011. Collapse: how societies choose to fail or survive. Penguin Books.

Future Pandemics.

Global Issues.

Inquisitr (2016).

Lovelock, James. 2009. The Vanishing Face of Gaia: A Final Warning. Basic Books, 288pp.

NIP Global.

Oxfam Blogs. 2008. What’s Kerala’s secret?

Sinclair, A.R.E. & Norton-Griffiths, M., 1979. Serengeti; Dynamics of an Ecosystem. Univ. of Chicago Press, 397pp.

Soapboxie. 2019. Population Development; What Kerala can teach India and China.

TED Talks, Bill Gates. Unicef. Wikipedia. Wikipedia.