There are many misconceptions about population - what the numbers say, what the impact is, and what population campaigners want to do about it.
Below are some of the most common that we encounter.
It just isn't. Unless we do something about it. The UN's median projection for future population growth sees us hitting 10.9 bn by the end of the century, and it still hasn't plateaued at that point. Even at the lowest end of the 95% certainty projection, population doesn't hit maximum until near the end of the century - at nearly 10 billion people. We can make that figure lower and bring about the end of growth sooner - but only if we take the action needed, now.
Choosing to have smaller families (one, two or even no children) is exactly how we end population growth and ultimately achieve a sustainable population on the planet.
The United Nations' main projection for future population is 10.9 billion people by 2100, based on assumptions about how large people's families will be across the world over the next 80 years. It also calculates that if, on average, every other family had just one fewer child than predicted ('half a child' less per family), there would be 1 billion fewer people by 2050 and our population would be lower than it is today by 2100.
Environmental crises like the sixth mass extinction and climate change demand urgent action. Addressing population is a key part of the solution to those and multiple other environmental problems. The choice is not between addressing population and taking other forms of action - we must do both.
In 2017, thousands of scientists from more than 180 countries signed a call for action detailing the gravity and urgency of the environmental threats of our time. Speaking of "widespread misery and catastrophic biodiversity loss" unless humanity urgently changes its ways, their Warning to Humanity says:
"We are jeopardizing our future by not reining in our intense but geographically and demographically uneven material consumption and by not perceiving continued rapid population growth as a primary driver behind many ecological and even societal threats."
Now signed by more than 20,000 scientists, the Warning to Humanity calls for goverments to take action to reduce fertility rates and for nations and governments to support the goal of a sustainable human population.
The gross inequalities that exist between nations and sometimes within nations are an outrage that must be addressed. Many of us consume far more of the Earth's resources, and contribute far more to environmental problems like climate change, than billions of poorer people in the world. In a world in which hundreds of millions have too little to eat and nearly two billion are obese, the distribution of resources is clearly a grave injustice.
An uneven and unjust distribution of resources, however, does not mean the Earth can indefinitely and sustainably provide enough to go round.
At the most basic level, everyone needs food and water. The Food and Agriculture Organization estimates we will need 70% more food by 2050 but climate change is making agricultural land unproductive, while the UN estimates that soil erosion, unless unchecked, means we have less than 60 harvests left. The Massachusetts Institute of Technology has calculated that by 2050, 5 billion people will live in "water-stressed" regions - meaning that they cannot rely on their water supplies to meet their needs.
The landmark 2019 EAT-Lancet Commission on feeding the world sustainably concluded that, with radical changes to food production and consumption, providing enough nutrition for everyone is possible. Critically, it also concluded that even these profound changes are unlikely to make it possible to feed everyone in just a generation or two from now if current population projections come true.
“ 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 becomes increasingly unlikely past this population threshold.”
EAT-Lancet Commission, 2019
Of course, people need and use far more than food and water. The International Research Panel projects that we will need 70% more resources each by 2050. This is partly because hundreds of millions of people are becoming more affluent, with their consumption of resources rising accordingly. Often, these rising demands are in places where there is also a high birth rate. This combination makes for a perfect storm of resource use.
A more equitable and just global system is urgently needed. There must be a convergence in living standards, where the rich take far less and the poor have far more. While we continue to add people and their inevitable demands for resources to the population, however, we are putting pressure on the Earth that it cannot sustain.
It can be, and is, about both. While it is clear that we need to change our consumption habits, adding more consumers only exacerbates every problem arising from it. The reality is that hundreds of millions of people have an absolute right to consume more, as they move out of poverty. In many cases, these people are in countries with high birth rates.
Those of us in the rich world especially need to live more sustainably as societies and as individuals. Stopping more consumers being added to the global population is another, and vital, way of reducing our overall consumption.
In the 1970s, our patron Paul Ehrlich and his colleage John Holdren proposed an equation to represent the factors which impact on the environment:
I = P x A x T
"I" is impact, "P" is population, "A" is affluence and "T" is technology. The "IPAT" equation shows that our numbers, how we live, and the technology we use all have an effect. We must not set up a false opposition between consumption and population. Both must be addressed.
This isn’t the case. Those young people will also become old. The idea that we need more people to support older generations is an unsustainable pyramid scheme – benefiting the present generation at the expense of the next.
Instead we need to grasp the opportunities presented by an ageing population, including less unemployment, a stimulus to greater productivity - especially exploiting new technology - and the availability of fit, talented retired people to contribute to our communities. We must address the challenges creatively and positively, and if we truly value our older people, that includes investing more resources in their wellbeing. Recent reports have highlighted the opportunities available and how important it is to reframe the debate about ageing.
The alternative to a creative and positive approach to ageing is constantly increasing our population in a vain attempt to catch up. That means continued climate change, continued biodiversity loss and continued depletion of the Earth's resources. We can provide better support for the elderly if we choose. We cannot bring back melted glaciers or species which have gone extinct.
You can. Coercive measures, like China's one-child policy, are not needed and abuse people's human rights. Time and time again, fertility rates have been brought down quickly and substantially in many parts of the world through ethical, positive measures.To address our current environmental crisis and achieve a global population that the Earth can sustain and a decent quality of life, we have to do more, better and quicker than we've ever done before. That goal is achievable.
The recipe is proven and simple, and improves people's lives in multiple other ways:
People in the developed world, such as Europe and America, have a disproportionate impact on the planet. For example a person in the UK produces 70 times the CO2 of someone in Niger. That means that fewer people being born in these countries has the most immediate and positive impact on our environment, climate and sustainability.
Many assume that technological progress will allow us to feed the world sustainably and to stop depleting natural resources, despite our increasing numbers. However, even technology does not enable limitless growth on a finite planet.
When Norman Borlaug was awarded the Nobel Peace Price in 1970 for his pioneering work to increase crop yields, he highlighted the impermanence of technological fixes under population growth:
"The green revolution has won a temporary success in man's war against hunger and deprivation; it has given man a breathing space. If fully implemented, the revolution can provide sufficient food for sustenance during the next three decades. But the frightening power of human reproduction must also be curbed; otherwise the success of the green revolution will be ephemeral only."
In addition, as people escape poverty, their consumption increases. In Asia for example, meat and seafood consumption is expected to rise by 78% by 2050, due to increasing wealth and population growth. We cannot expect food and agricultural technology to rapidly meet this exploding demand with a fully sustainable alternative.
A 2017 study by the Massachusetts Institute of Technology found that no matter how much more efficient and compact a product is made, demand for that product will continue to grow (due to better performance and reduced cost), leading to increased material use and resource extraction. The researchers looked at 57 common goods and services, including polyester fiber, laser diodes and crude oil, and found that despite technological improvements in almost all cases, there was not a single case of 'dematerialisation' (an overall reduction in materials).
Technological innovation has lead to important environmental progress, such as harnessing renewable energy, but it has also hastened environmental destruction, for example by enabling extraction and burning of fossil fuels on a massive scale. Technology is a double-edged sword that represents an important tool in solving our biggest problems but it is certainly no miracle cure for environmental crises.
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