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Cities are the global battleground for a sustainable future

Adrian Malleson

The huge benefits of cities come at a terrible cost. Architectural expertise can help steer the world's increasing urbanisation towards a more sustainable future

Bristol has structured local policy around the UN sustainable development goals.
Bristol has structured local policy around the UN sustainable development goals. Credit: Istock

‘Our struggle for global sustainability will be won or lost in cities’ – the words of former UN secretary-general Ban Ki-moon. It’s true; if we don’t get cities right, we lose the fight for a sustainable future.

Cities represent a remarkably successful way of living; they power economic growth, research and culture. As people join together, innovation flourishes, ideas are shared, specialism increases and output goes up. Cities are the frenetic breeding ground for more, new, better, affordable things, experiences and ideas. Although occupying less than 3% of the world’s area, cities contribute 70% of global GDP. In the UK, for example, London alone creates around a quarter of UK GDP; it is set to remain among the global top five cities for years to come.

For all that, cities come at a terrible cost. While 55% of the global population lives in them, they create 70% of global waste, account for 60% of energy consumption and generate 70% of global greenhouse gas emissions. Nine out of 10 people living in urban areas are breathing air that contains high levels of pollutants, causing 7 million deaths. If cities continue to grow and consume as they do currently, the fight for sustainability will be lost. Architectural expertise is urgently needed to help make the best or urbanisation. 

Urbanisation and the growth of the city

The global trend for urbanisation is one of the defining characteristics of the post-industrial revolution era. If you want a megatrend, here’s one: in 1950, 750 million people lived in cities; that figure is now 4,370 million. This year, it is set to be over 6,500 million. To put it another way; today, 55% of the world’s population lives in urban areas; by 2050 that proportion is expected to be 68%.

Another megatrend: the number and size of cities will continue to grow fast. One in five people now lives in a city with more than a million inhabitants. At the turn of the millennium, there were 371 cities with 1 million inhabitants or more. Now there are over 550. By 2030, it is likely to be more than 700 – almost double in 30 years.

By 2030 there are likely to be over 40 ‘megacities’, those with more than 10 million inhabitants. In 1950 there was just New York.

As the graph shows, this growth in urbanisation and cities is felt most keenly among low and middle income countries, particularly in Asia and Africa.

Urbanisation is one of the biggest global challenges we face; it’s also one of the biggest opportunities. The opportunity is for cities to continue to play their historical role in dramatically improving life expectancy and the living and educational standards of those who live in them. The challenge for city dwellers includes high levels of inequality, failing motorised transport, poor sanitation and growth of informal settlements. The challenge for us all is the unsustainable growth of city-generated greenhouse gases.

Cities and sustainability

In response to these possible futures, in September 2015, at the United Nations General Assembly, 193 nations agreed to adopt the UN sustainable development goals (SDGs); a ‘universal, integrated and transformative vision for a better world’.

Cities were given a sustainable development goal all of their own: Sustainable Development Goal 11: Make cities and human settlements inclusive, safe, resilient and sustainable.

Through SDG 11, we can secure a sustainable future for our cities; and through our cities, we can secure a viable future for us all.

The broad ambition of this SDG11 is underpinned by a series of specific targets, such as decent, safe and affordable housing (target 11.1), or access to safe and affordable transport (target 11.2). These targets are measurable, and so can be acted on, and those actions assessed. Safe and affordable housing, for example, is a global issue. In 1990, almost half of the world’s population lived in slums; by 2014 that had fallen to 29%. But decent housing is not just an issue for low or middle income countries; in the UK 18.5% of households live in a place that fails one or more of the decent homes criteria. As a nation, we too are failing to meet SDG 11, failing to house our citizens decently.

Locally some UK cites have risen to the challenge of the SDGs by structuring local policy around them. Bristol City, for example, has mapped its city plan to the SDGs and provided a handbook to help other cities do that too.

Planned cities are better cities. Unplanned cities typical have poor housing, inadequate transport, higher emissions and sprawling suburbs. A standards and regulatory environment that supports town planning and good building design makes it more likely that city dwellers will live decent lives, create shared prosperity and minimise environmental degradation. Our expertise is globally needed. The Commonwealth Association of Architects reports a continuing critical of lack the professional capacity needed in urbanising countries.

Cities and disease

As Covid-19 spreads, the relationship between cities and disease is again made clear to us. Cities’ power of agglomeration can very rapidly flip to become the weakness of contagion. Disease has long shaped cities. We can look back as far as Athens in 430BC, to a disease that permanently diminished its power.

Covid-19 is having a profound effect on urban living and urban economies. Over 90% of cases are in urban areas. So far, over 1,430 cities in 210 countries have been affected by Covid-19. What looked at first like just a hiatus in our way of living is increasingly making us ask fundamental questions about how we work, shop, move about and spend time with one another. The answers to these questions may radically change the future urban form. It will also change our future economy, what we produce, where we produce it and what methods of production we use.

While cities allow the rapid spread of disease, as urbanisation has increased, so too has life expectancy (by 5.5 years, for example, between 2000 and 2016). Our hope for a solution to the Covid-19 crisis rests in city-based intuitions, our universities, our pharmaceutical industry.

The solution to our current crises, the climate emergency and disease won’t be for us to be more rustic. To misquote Orwell, if there is hope, it lies in the cities.


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