The Shibuya Crossing in Tokyo (tomlamela/iStock)

The world’s population is 7.8 billion people and rising. Just over 200 years ago, the total was not even 1 billion.

The pace of growth concerns environmentalists. In his recent Netflix documentary, A Life on Our Planet, David Attenborough details the damage: deforested jungles, polluted air, and oceans choked with plastic. He says population growth must come to a halt sooner rather than later.

The argument is logical: an extra person is an extra consumer and polluter. However, the link between environmental degradation and population growth is far from new, and those who declared we are bound to grow and consume beyond sustainable levels failed in their predictions.

The assumption that population size is the most significant demographic component in greenhouse gas emissions is inaccurate and misleading. Consumption and production patterns differ greatly between regions and between different cohorts of the population within a country.

Over the next 30 years, there will be significant and diverse changes in the structure of populations in the developed and developing world. Understanding these is key to combating the climate crisis.

The Developed World

Declining levels of fertility and high life expectancies have produced aging societies in the developed world. The average age of a person in the European Union is 43 and is projected to increase to 48 over the next 30 years. In Japan, the expected average age will be 54 by 2050.

Aging societies are largely beneficial for the environment, as a smaller workforce means less emissions from the industry and agriculture. Continued urbanization may also be a positive: in Europe, carbon footprints are on average 7% lower in cities than in rural areas. In the past 30 years, EU greenhouse gas emissions have fallen 30% as the population has expanded by 4%. With a projected 30 million fewer inhabitants by 2050, the EU can reach emission targets with careful planning and policies to maximize potential green gains.

However, there is the anomaly that a declining population does not correspond with a decline in households, as Japan and South Korea have shown. Between 2010 and 2015, the number of Japanese households increased by 2 million despite the population declining by 1.2 million over the same period.

The process has already begun in Italy where household numbers are rising every year even though the population has declined by 500,000 since 2015. Eastern Europe is experiencing a similar trend and Western Europe is on track to follow suit.

With household energy use in the EU accounting for approximately 20% of greenhouse gas emissions in the past 10 years, the fall in emission rates will be limited from this expanding sector. So, to maximise green gains from changing population structures, investment in clean urban transport and the construction of efficient residential accommodation should be at the forefront of climate action plans.

The Developing World

Over the next 30 years developing nations will account for almost all of the world’s population growth. The population of Africa will double to 2.2 billion in 2050 and is projected by the UN to reach 4 billion in 2100.

At present, bulging populations of sub-Saharan Africa do not significantly contribute to global emissions, with the African continent still only accounting for 4%. However, if the desire for development is fulfilled, lifting hundreds of millions out of poverty, can the environment be protected?

Africa’s young population and increased urbanization are the primary demographic factors that will affect emission rates. The East Asian example has pointed to a correlation between urbanization, economic growth, and the sharp increase in carbon dioxide. In China, the percentage of urban dwellers has increased from 25% to 50% since 1985, corresponding with a 400% increase in emissions. The level of population growth declined every year over that period, and now stands at 0.4%, indicating that population growth has not been the primary cause of increased emissions.

Africa stands in a similar demographic position to 1980s China. A population of just over 1 billion with an average age 20 years and mass rural-urban migration. One significant difference is that Africa’s population is growing at a substantially faster rate which ironically may be of benefit to the environment.

As half of people in sub-Saharan Africa have no access to electricity, massive renewable energy engineering projects are seeking to provide power to all by 2050. Kenya has doubled the share of its population with access to electricity from 30% to 63% between 2007 and 2017, using sources such as wind and geothermal power that account for 75% of Kenya’s electricity.

Europe and North America industrialized before understanding the consequences of fossil fuel consumption. In Asia, countries industrialized while wearing environmental blinkers. Africa has the opportunity to break the link between development and emissions.

Policy, Not Population

The future of the climate is not dependent on the level of population growth. Policy and innovation are the crucial factors.

Greater numbers of people may aid the development of infrastructure and technology transfers, critical to tackling the climate crisis. Densely populated cities are hubs for knowledge and resource production, as in the agricultural Green Revolution of the 1960s and 1970s, driven by teams of top scientists collaborating in universities in the biggest cities in North America. The developments in agriculture in the 1970s are estimated to have saved 1 billion people from starvation in the 1980s.

Progress in environmental engineering is following this blueprint. Hydrogen cell power and perovskite solar cells are predicted to be game changers in the coming decades.

If we are to survive the climate crisis, innovation is our hope. The more people involved, the better.