John Barwise considers the implications of a growing global population that lives longer.

An ageing population is one of the Industrial Strategy’s four grand challenges. The world’s population is constantly increasing and this is partly because the percentage of the population that is 65 years or older is growing. The Office for National Statistics (ONS) projects the 65-plus sector to grow from 17.8% of the UK population in 2015 to nearly 25% by 2045.

Globally, population growth is heading inexorably towards nine billion by 2050. Is this population growth the trigger for environmental disaster?

Earth Overshoot

As populations rise, pressure on the world’s natural resources grows and the state of the environment inevitably deteriorates, with long-term consequences for human health and economic development.

There were fewer than one billion humans living on the planet 200 years ago. Last century, world population quadrupled from 1.5 billion to 6.1 billion. Today, there are over seven billion, adding further pressures on the resources needed to sustain life on Earth.

Are we pushing the Earth beyond its natural carrying capacity?

Mathis Wackernagel, co-founder and CEO of Global Footprint Network, thinks so. In a quote for Croner-i earlier this year, he said: “While economies, populations and resource demands grow, the size of Earth remains the same. That’s a reality we need to carefully track.”

Wackernagel’s comments followed this year’s Earth Overshoot assessment — the date in the calendar when humanity’s annual demand on nature exceeds what Earth can regenerate in the whole of that year. In 2018, Overshoot happened on 1 August, earlier than all previous years and highlighting concerns that we are consuming the Earth’s resources at a faster rate than ever before.

Major crises such as climate change, water, soil and food depletion, biodiversity loss and the degradation of land and seas are now reported on a daily basis, and the underlying causes of these events are rising populations and overconsumption.

However, delving a little deeper into consumption, population growth and their relative impact on global resources, a picture emerges of widespread disparity between developed countries and developing economies.

Population growth

First, the good news. While the global population is continuing to rise, the rate of population growth is levelling out and is even falling in some developed countries. Natural population levels across the EU, for example, have overall fallen gradually in recent decades, due mainly to net migration.

Similarly in the USA, population growth is in decline which, according to Mark Mather, Associate Vice President of US Programs, is due to lower levels of immigration, population ageing and declining fertility rates.

Lifestyle changes in developed countries are also changing population demographics. Women in the West are no longer socially or economically dependent on men and are deciding to have fewer children later in life. The total fertility rate (TFR) — the reproduction rate that keeps a population stable — is 2.1, yet for many developed countries, the birth rate has fallen below this. TFR in the USA stands at 2.0, in the UK it is 1.9, in Belgium it is down to 1.8 and in Italy it is even lower at 1.4.

In contrast, fertility rates in developing countries are much higher. According to the 2015 Revision of World Population Prospects, Africa is the region with the highest average fertility rates at 4.7 children per woman. Oceania, which includes Australasia, Melanesia, Micronesia and Polynesia, is at 2.4 children per woman. Both Asia and Latin America and the Caribbean have a TFR of 2.2.

Family planning

There are many reasons why developing countries have higher birth rates: child mortality rates are higher, children do essential work, particularly in agricultural communities, and young people are expected to look after their parents in old age. Gender inequality and other cultural differences are also key factors. But equally important, and some would argue more relevant, there are more women of childbearing age in poorer countries who don’t have access to the education and family planning services that are available in richer countries.

According to the World Health Organization (WHO), more than 214 million women of reproductive age in developing countries who want to avoid pregnancy are not using contraceptives because of lack of access to family planning information and services and lack of support from their partners or communities. A UN Policy Briefing estimates that family planning needs of 23% of women in the least developed countries are not being met.

Yet, there is growing evidence that TFR in some African countries and other regions is also starting to fall, and some countries, such as Mauritius, Seychelles, South Africa and Cape Verde, have rates below many western countries. The USA-based Wilson Center says one reason for this is a growing awareness in developing countries that lowering birth rates can increase economic growth. The recently agreed $2.4 billion funding from global agencies has also increased access to family planning services in a number of developing countries.

The age factor

At the other end of the human life cycle, life expectancy in developed countries is increasing, leading to an ageing population — with many countries registering 20% or more people over the age of 65. UN data of life expectancy in 2015 puts Japan at the top of the league table with overall life expectancy at 83.74 years. Italy, Switzerland, Iceland, Spain and Sweden are all in the top 10.

The UK comes in at 28 in the league table, with a life expectancy at birth for men at 79.2 years and women, 82.9 years, up from 70.8 years for males, and 76.8 years for females in the early 1980s. In 2017, there were 1.35 million people aged 85 and over in England — nearly three times more than in 1971, although this growth has slowed in recent years. The USA is lower than most other high-income countries and comes in at 43rd in the league table with a combined life expectancy of 78.88 years.

Life expectancy for developing countries tends to be at the lower end of the league table, with many below 60 years for men and women. But the age cohort is changing, with some populations starting to live longer, as living standards improve and healthcare services become more widely available.

A report produced by Priya Shetty and published in the Lancet shows the proportion of older people is increasing in almost every country of the world but most notably in poorer countries where, by 2050, one in five people will be over 60 years old. The report points to falling fertility rates, and increased life expectancy, especially in Asia, as the main reasons for the rapidly ageing population.

However, the report comes with a warning. The health systems of many developing countries are struggling to balance the resources needed to fight infectious diseases against the growing epidemic of chronic diseases such as heart disease and diabetes. Increasing longevity also brings new illnesses associated with old age, such as dementia and Alzheimer’s disease, which most developing countries are ill-equipped to deal with.

Demographic transition

Demographic transition describes the changing pattern of mortality, fertility and growth rates as societies move from one demographic regime to another.

Poorer countries are progressing through a demographic transition that richer countries have been going through for over two centuries — only at a faster rate. According to a report in The Economist magazine, the transition from a rate of five children to just two, which took 130 years to happen in Britain, took just 20 years — from 1965 to 1985 — in South Korea. “Mothers in developing countries today can expect to have three children. Their mothers had six,” the report points out.

Other similarities with richer countries include higher economic growth. With fewer mouths to feed and reduced welfare needs, parents can choose to work longer and generate more wealth, which in turn improves living standards and creates a healthcare buffer for their families and old age.

Reality check

Around two-thirds of the world’s people still live in poverty and most of these live in countries that are not yet developed, including some regions in Latin America and parts of Asia and sub-Saharan Africa. According to the World Bank, the problem of global poverty continues to be one of enormous magnitude even if the number of people living in extreme poverty is falling.

However, as we have seen with developed countries, economic growth and better living standards mean higher rates of consumption — energy, water, food and minerals, etc — which add further pressure on natural resources and global warming.

A report commissioned by The Royal Society in 2012, People and the Planet, points out that material consumption per capita in the richest parts of the world, “is far above the level that can be sustained for everyone in a population of seven billion or more”. In contrast, the report points out that the world’s 1.3 billion poorest people need to consume more to escape extreme poverty.

The evidence is clear enough. Take carbon footprinting, for example. Emissions per capita in Qatar are the highest in the world with 39.7t/capita, the USA comes in at 16.1t/capita while the EU emits 6.9t/capita a year (the UK emits 6.1t/capita). By comparison, Indonesia emits 2t/capita, India 1.9t/capita and Nigeria just 1.1t/capita a year.

Ecological footprinting follows similar trends. Luxembourg has an ecological footprint of 15.82 global hectares per person (gha/capita), Australia 9.31 gha/capita, the USA 8.22 gha/capita, the UK 7.93 gha/capita and Germany 5.3 gha/capita. At the lower end of the league table, Madagascar, Mozambique, Malawi, Pakistan and Bangladesh all have footprints of less than 1 gha/capita.

Most developed countries, and a growing number of developing countries, have an “ecological deficit” where the footprint of the population exceeds the biocapacity of the country. Data from the Global Footprint Network estimates that to sustain the current rate of global consumption of natural resources requires 1.6 planets, rising to two planets by 2030.

Australia would need over five planet Earths to sustain its current level of consumption, the USA would need 4.8 Earths, Germany and France would need three Earths and the UK would need 2.9 Earths. In contrast, if all developed countries consumed at the same level as India, which currently has an ecological footprint of 0.7 Earths, we would still be living within planet Earth’s carrying capacity.

This isn’t going to happen, so where do we go from here?

Taking stock and moving forward

All the evidence indicates that planet Earth does not have the biocapacity to sustain population growth and rising resource consumption. The scale of environmental change and the rate at which it is happening are so immense that this period in planetary history has earned the dubious title of the Anthropocene epoch, marked by the dramatic and irreversible human impact on the Earth’s geology and ecology over the past 200 years.

Current levels of consumption are very much skewed to wealthier countries, largely through increased economic growth from rapid industrialisation.

As industrialisation shifts to less developed countries, many are starting to show similar trends. China, for example, has the second biggest economy with a predicted GDP of around 6.6% for this year. India is currently the fastest growing economy with a growth rate of around 7.3% for this year, rising to over 8% next year.

Together, China and India account for over 36% of total world population. Assuming a trajectory of lower birth rates and increased consumer spending as experienced in most western economies, it would be reasonable to assume that pressures on resources and the environment will only intensify over time.

There are ways to limit these impacts. The People and the Planet report, for example, recommends that developed and the emerging economies stabilise and then reduce material consumption levels and decouple economic activity from environmental impact. This can be achieved through improvements in resource use efficiency, including reducing waste and investing in sustainable resources, technologies and infrastructures.

There is also the potential for more sustainable urbanisation. For the first time in history, more than half the world’s people live in urban communities and by 2030, 60% of the global population will live in cities. Building sustainable cities that incorporate high-tech transport systems, energy-efficient homes and workplaces, better recycling and smart drainage, etc can significantly reduce the ecological footprints of people who live there.

These concepts are only part of the solution to an emerging crisis. More research is needed to explore the interactions between material consumption, including food and environmental impacts and how these are influenced by demographic change.

There has been huge progress in finding solutions to global warming and climate change. But even if the target of only 1.5°C temperature rise is achieved, there is clearly more work to do on finding long-term sustainable solutions to population growth and material consumption.

Last reviewed 3 January 2019