How to feed a ballooning world population
Science of Life

The population of the world is growing fast and is projected to increase from its current level of 7.4 billion to 10 billion later this century, although some estimates project a less steep rate of increase. Coping with this increase undoubtedly poses challenges and, in particular, there are concerns about our ability to feed such a large number. 

Although there is a growing confidence that enough extra food could be grown to feed 10 billion people, we now know that, if current eating patterns persist, a secondary problem will arise from producing all this extra food – environmental degradation. However, a new study released by the Institute of Social Ecology and published online in Nature Communications claims that the extra food necessary to feed 10 billion people could be produced without causing any more environmental degradation, if we all switched to a vegan diet.

The annual world population growth rate peaked in the 1960s reaching a maximum of 2.19% in 1963. The rate is currently declining and this decline will continue during the coming years. 

Growth rate

The world population is currently growing at a rate of 1.13% per year. It is estimated that this growth rate will decline to less than 1% by 2020 and to less than 0.5% by 2050. The overall world population will continue to grow during this 21st Century but at a slower rate than in the recent past. 

The world population doubled in 40 years from 1959 (three billion) to 1999 (six billion), but a further 39 years will have passed before the population has increased by another 50% to become nine billion in 2038. The UN projects the world population will reach 10 billion by 2056.

Despite what many people assume, we currently produce much more food globally than we actually consume, e.g. much food is wasted and the means to transport food to where it is urgently needed is often lacking because of wars and so on. 

Future technological advances will almost certainly allow us to grow more food on poor ground. But, growing all the food needed to feed an extra three billion people could cause a very significant secondary problem. 

At the moment we eat a lot of meat which means grazing lots of livestock on open land. If we continue our current eating patterns much more open land will be required for livestock, which will inevitably call for deforestation to create this open land. But deforestation degrades the environment and exacerbates global warming. For example, forests suck carbon dioxide out of the air thereby reducing the concentration of this warming gas in the atmosphere. 

Cattle also produce copious amounts of methane, the warming gas, into the atmosphere.

However, in their latest study the Institute for Social Ecology estimates that enough food can be produced to feed the entire world at least to 2050 without cutting down any more trees if we all stopped eating meat and became vegans. Neither vegans nor vegetarians eat meat, but vegans also avoid eating any animal products e.g. eggs. Vegetarianism is usually a diet whereas veganism is a lifestyle. Vegans have much stronger political views than vegetarians, believing that animals should be protected by many of the same laws that protect humans. 

A vegan diet, if adopted by everyone, would work best to obviate the need to cut down forests to graze livestock, but a vegetarian diet would also work well in this regard. A vegetarian diet can be just as healthy as a diet containing meat once care is taken not to allow any deficiency to arise in consumption of certain nutrients that are easily and plentifully available from meat.

This Institute for Social Ecology analysis is very interesting but, to be honest and practical about the matter, we should immediately acknowledge that there is no way everybody in the world is going to become vegetarian, let alone vegan. However, this does not mean that this analysis is of no practical value. 


We can safely conclude I think that, although everyone will not go vegetarian, the environment would be greatly helped if we all reduced the amount of meat we eat. I suppose I am a typical meat eater – I eat meat every day. But it wouldn’t be any great hardship on me to eat meat only every second day, or even every third day. If we all did this it would greatly ease the pressure to keep expanding the production of meat as the world population increases.

Catholics are now officially obliged to take action to mitigate the effects of climate change. In his recent encyclical, Laudato Si’, Pope Francis says that the Earth, created to support life and give praise to God, is crying out with pain because it is being destroyed by human activity. 

While acknowledging that science is not an area in which the Catholic Church has expertise, Pope Francis says “a very solid scientific consensus” points to global warming and indicates “human activity” has seriously contributed to this problem, threatening the Earth and all life on it. “We know that technology based on the use of highly polluting fossil fuels – especially coal, but also oil and, to a lesser degree, gas – needs to be progressively replaced without delay,” he says.

Pope Francis says that all who believe in God and all people of good will are obliged to take steps to mitigate climate change in diverse ways, for example by recycling paper, using public transportation and putting on more clothes instead of raising the heat in the winter. 

He also insists that wealthier nations, who contributed more to despoiling the Earth, must bear more of the costs of remedying the damage. As I explained earlier, eating less meat is a relatively painless way by which we can all take action to mitigate the effects of climate change.


*William Reville is an Emeritus Professor of Biochemistry at UCC