Population Change

Changes in births, deaths and patterns of migration are reshaping populations, influencing the size and shape of people’s families and the makeup of the communities within which they live. These trends are already affecting the design of the built environment.

RIBA Horizons 2034 sponsored by Autodesk

According to the United Nations, on 15 November 2022 the world’s eight billionth citizen was born in the Dominican Republic. [1] The UN described it as “a milestone in human history” – the culmination of an era where dramatic improvements in diet, sanitation, education and income have led to better health, resulting in an acceleration in the size of the global population.

It took all of human history for the world to reach its first billion at the dawn of the 19th century. The pace of change then quickened as the Industrial Revolution spurred on economic growth and social change, with the landmark of the second billion reached in 1930. Since then, the time between successive billions has shortened, with the result that, within the lifetime of someone born in the early 1970s, the world’s population has doubled from four billon to today’s eight billion.

It is widely accepted that the global population cannot continue to grow at such a pace. Most demographers believe that the world’s population will stabilise at around 10.4 billion at the start of the next century, ending three centuries of population growth. [2]

So where might we be in 10 years’ time in 2034? Population growth is already slowing as families adjust their behaviours, with parents choosing to have fewer children. Fewer births mean that the world’s population is changing in shape, moving from the classic ‘population pyramid’ – with lots of children at the bottom and few older people at the top – to a ‘population rectangle’ where there will be similar numbers of people at each age. In short, this means that we have an ageing population.

The population change theme for RIBA Horizons 2034 considers four challenges.

The first is how architects should respond to changing demographics. How do we design for tomorrow’s population, with more single person households, smaller families and more generations alive simultaneously? How do we ensure that our (smart) homes can age with us, enabling us to continue to age in place and remain living in the community? And how can cities be designed to support an ageing society?

Not all parts of the globe have gone through this demographic transition at the same time or pace, meaning that the spatial distribution of the global population has changed and will continue to do so. Europe and North America are projected to reach their peak population this decade, and indeed some countries within these regions are already experiencing population decline. In contrast, the population of sub-Saharan Africa is still growing and is expected to almost double by 2050, surpassing two billion inhabitants.

Urbanisation is the second population challenge. The diversity in population growth, allied with stark differences in economic and social life chances between countries and areas within countries, means that more people than ever are on the move.

Today, four and a half billion of the world’s eight billion citizens live in urban areas and this is likely to increase by a further two and a half billion by 2050. [3] Rural to urban migration has seen the emergence of megacities – that is, cities with over 10 million inhabitants – in China, India, Latin America and parts of sub-Saharan Africa, with all the challenges this creates for the built environment and the supply of services.

As well as moving from rural to urban settings, more people than ever are moving across international borders and so migration and displacement is our third population challenge.

According to the UN, the number of persons living outside their country of birth or citizenship reached 281 million in 2020. [4] Today, international migration helps to maintain the population size and labour force in countries where the birth rate is low, adding to the cultural diversity of villages, towns and cities across Europe.

However, skilled economic migrants are just part of the picture. The past decade has witnessed a marked rise in the number of people displaced because of armed conflict and famine, with mass movements of refugees and asylum seekers. How should architects respond to these movements?

The final population challenge – the increasingly diverse population – brings together aspects from all three previous challenges. The built environment professions need to respond to the increasingly diverse makeup of our communities, creating places that meet the needs of different age groups and communities while promoting social cohesion.

Looking forwards

Population change over the next decade will provide exciting opportunities for designers, while presenting some resourcing challenges, meeting a skills gap.

With cities in the Global South expanding rapidly, often in unplanned ways, the need for design professionals to drive equitable and sustainable development has never been higher. In many low- and middle-income countries, developing collaborative ways to advance, retain and enlarge the pool of those much-needed professionals is a priority.  

Moreover, the UN population projections used here assume that the IPCC target to limit average global warming to 1.5°C above pre-industrial levels will be met by the end of this century, which may be optimistic. Should we fail to adequately address the climate challenge, global displacement and forced migration because of rising sea levels, desertification and the increased risk of natural disasters will be on a much bigger scale than anticipated.

Going forward, built environment professionals need to be aware of the complex nexus between environmental and population change, taking care to minimise their impact upon the environment while addressing the need for housing and public infrastructure for our changing population.

About the author

Jane Falkingham is Professor of Demography and International Social Policy at the University of Southampton. She is Director of the ESRC Centre for Population Change whose remit is to better understand the drivers and consequences of demographic changes.

References

[1] United Nations (n.d.). Day of 8 Billion

[2] United Nations, Department of Economic and Social Affairs, Population Division (2022). World Population Prospects 2022: Summary of Results

[3] United Nations, Department of Economic and Social Affairs, Population Division (2019). World Urbanization Prospects: The 2018 Revision (ST/ESA/SER.A/420)

[4] United Nations, Department of Economic and Social Affairs, Population Division (2020). International Migration 2020 Highlights (ST/ESA/SER.A/452)