We have only one Earth. Today, the 8 billion people on it are using more of its resources than it can provide. Every new person is a new consumer, adding to that demand. Some of us take far more than others and there are many steps those of us who do must take to make our consumption sustainable. Fewer new consumers everywhere is one of them.

Increasing resource use is the main driver of the triple planetary crisis of climate change, biodiversity loss and pollution.

– United Nations Environment Programme, 2024

out of control

Our total global extraction of materials from the Earth has tripled in the last 50 years, and is expected to grow by 60% in the next 25 years – unless things change. According to a 2024 report by the UN Environment Programme, more than a quarter of our increased material use since 2000 is as a result of population growth.

renewable resources

Everyone understands that many of the Earth’s resources are finite. We are currently completely reliant on fossil fuels, iron and other metals, minerals and even such basic commodities as sand to keep the modern world ticking over. Adding more consumers makes those resources run out faster.

The Earth also provides for our needs with renewable resources, such as timber, clean water and air, healthy soils and wild fish consumed for food. However, our demands are so great that according to the Global Footprint Network, we are now using those resources at almost twice the rate that the Earth can renew them.

Some people believe that greater efficiencies in the use of resources mean we will use less of them. There is no evidence to support that, however. A study by the Massachusetts Institute of Technology in 2017 evaluated the use of raw materials such as crude oil and silicon and found that greater efficiencies led to price reductions, making commodities more affordable and, increasing their demand and usage. They investigated more than 60 materials and found that only in six was consumption decreasing.

The UN’s International Resources Panel has projected that resource use per person will be 71 per cent higher than today in 2050.

Food and water

More than 800 million people currently do not get enough food to meet their nutritional needs every day. Meanwhile, 650 million are obese. People go hungry today not because there is insufficient food but because our global economic system distributes it unfairly. In fact, the number of people suffering from hunger has actually increased in recent years – due in part to development progress not keeping up with rapid population growth.

Every extra mouth to feed puts more pressure on our food supply. That is already under threat from multiple factors, including shortage of fresh water, soil depletion, decimated populations of insect pollinators and climate change. The UN currently projects that we will need 70% more food by 2050. Increasing agricultural production comes at a cost to nature, however. Habitat loss and exploitation are the two most significant threats to biodiversity – currently, 80% of extinction threats to mammals and birds are due to agriculture.

A landmark report on diet and sustainability by the EAT-Lancet Commission in 2019 concluded that it is possible to feed a population of 10bn sustainably if radical action is taken to revolutionise dietary habits and food production. It went on to say, however:

Global population is expected to exceed 11 billion people by 2100 unless actions are taken to stabilise population growth. Healthy diets from sustainable food systems are possible for up to 10 billion people but become increasingly unlikely past this population threshold.

Action to address population is essential if we are to meet the most basic human right of all – ensuring people have enough to eat.

Water is an absolute basic human necessity, and each person adds to the demand, meaning threats to fresh water are even more critical. An MIT study concluded that nearly five billion people will live in water-stressed regions by 2050. The United Nations has calculated that water shortages as a result of climate change could displace hundreds of millions of people by 2030. Regional variations in water availability are extreme but many of the world’s poorest regions, and those which have high population growth, are among those with the shortest supply. Developed countries also suffer from the effects of population pressure on water supply. The densely-populated south-east of England is ranked in the bottom 10% of global regions for the ability to supply water to its inhabitants.

Pollution

As with every environmental problem, while there are many solutions to pollution, adding more people to the population adds more polluters and makes those solutions less effective. While rich countries produce more plastic waste per person, for instance, poor regions where population growth outstrips the infrastructure to dispose of waste may contribute more plastic overall.

Greed, need and injustice

Material footprint per capita in high-income countries is 60% higher than in upper-middle-income countries and more than 13 times the level of low-income countries.

United Nations

Vast disparities exist in consumption and impact between the rich world and the Global South and within countries themselves. A more just global system, in which resources are distributed more equitably, is essential. Whatever form that takes, in order to ensure that there is enough to meet everyone’s right to a decent standard of living, the richest must consume more sustainably – in other words, consume less. When nations leave poverty, their fertility rates reduce – but hand-in-hand with that increasing prosperity comes increased consumption. People should not have to compete for the Earth’s resources.

That’s why population and family size is an issue in both high-income and low-income countries. Where affluence and consumption is high, reducing the number of new consumers is an effective, permanent way of reducing the drain they place on resources, as well as their environmental impact. It does not mean that people should not do other things to reduce their consumption, or that wider issues of global injustice do not need to be urgently addressed. Nevertheless, reducing, through effective, ethical means, the number of affluent people consuming is an essential, effective method to relieve the pressure.

Population growth is still important. The 2024 UN Environment Programme report found that population growth is the main driver of increased resource use in Africa and West Asia.

In the low income countries, fewer people mean less competition for natural resources, especially local resources such as land and fresh water. In the longer term, fewer people being born means that as countries move out of poverty, their level of consumption will be lower.