A Journal of People report
Where shall the urban population growth reach? What shall be its impact? What is happening in urban life? Is this life-pattern sustainable? What is the root of the urban population-reality? These questions and similar questions are haunting all around the world.
The human population is growing at an alarming rate. By 2050, there will be almost 10 billion people on the planet.
Population growth in the US and Europe stagnates while the number of people living in the Middle East, Asia and Africa is going to skyrocket. Today, Tokyo is the most populous city in the world, with about 38 million residents. New York City is still in the top 10 ranking most populous cities, with its nearly 8.5 million people. But in the next three decades, that’s going to change.
By 2030, the cities listed below will be the new 10 biggest cities in the world, says the UN World Urbanization Prospects (United Nations, Department of Economic and Social Affairs, Population Division (2014). World Urbanization Prospects: The 2014 Revision, CD-ROM Edition):
- Mexico City, Mexico: 23.9 million people
- Lagos, Nigeria: 24.2 million people
- Cairo, Egypt: 24.5 million people
- Karachi, Pakistan: 24.8 million people
- Dhaka, Bangladesh: 27.4 million people
- Beijing, China: 27.7 million people
- Mumbai, India: 27.8 million people
- Shanghai, China: 30.8 million people
- Delhi, India: 36.1 million people
- Tokyo, Japan: 37.2 million people
The Global Cities Institute projects that Kinshasa, in the Democratic Republic of the Congo, will be the most populous city in the world by 2075, and that by 2100, it will be surpassed by the 88 million future residents of Lagos, Nigeria.
“Cities are all about density – groups of strangers agreeing to spend their lives in close proximity, whether for protection, mutual opportunity or simply the need to be together. In a world whose human population is now more than 50% urban, this condition is shared by most of humanity”, says a report by The Guardian.
The “Where is the world’s densest city?” headlined report said:
“The simplest definition of density is the amount of people divided by the land they occupy. On this basis, the 7 billion living humans divided by the land surface of the Earth means there is a population density of roughly 50 people for every sq km. Evenly spread over all the world’s mountains, deserts and other terrains, we’d be standing about 150 metres away from our neighbour.
“While there is no internationally agreed definition of the boundary of a city, measuring the density of “urban agglomerations” – including adjacent suburbia as well as the administrative city proper – gives a decent comparative picture.”
The report by Douglas Murphy said:
“The UN’s Habitat data, collected from national census offices, gives the number one spot to Dhaka, with a density of 44,500 people per sq km. It’s mostly Asian cities in the top of the list: Mumbai is second, while Manila is fourth, with Singapore high up as well. Medellin is South America’s most dense city at third overall, with Casablanca and Lagos in Africa close behind.
“But different measures give different results. The UN’s Demographic Yearbook has data for the “city proper”. This smaller measurement of area makes Manila the world’s most densely populated city, with the centres of Paris, Athens and Barcelona topping the European list. New York is the densest city in North America, while sprawling Sydney is Australia’s.”
The May 11, 2017 datelined report questioned:
“What causes high density?”
“While the roots of urban growth are complex and interlinked, there are factors that simply force people to live in high-density environments. Prime among these are natural boundaries. Malé, the capital of the Maldives, is an island city with an area of just 5.8 sq km and a population of more than 130,000 people. It doesn’t have super tall buildings or other spectacular architecture, but having to build on all possible scraps of land means it has a density of 23,000 people per sq km.
“This island effect can lead to real extremes. Before it was abandoned and became a hallowed site of modern ruins, the offshore coal mine of Hashima Island near Nagasaki had more than 5,000 people living on an area barely 400 metres long, giving it a density above 83,500 people/sq km.
“Another cause of density are defensive boundaries. From Iron Age hill forts to medieval castles, military protection encouraged populations to huddle together within walls. In Europe, by the end of the 17th century, the ultra-sophisticated, space-hungry bastions and ravelins that surrounded many cities were in danger of strangling life within. The effect of this military encirclement still applies today in the besieged Gaza Strip – which is completely blocked in by Israel and Egypt and has the fifth highest population density of any territory on the planet.
“And then there’s the exploitation of verticality. Ancient Rome is believed to have reached a population of over 1 million inhabitants (although this figure has been disputed), many of whom were packed into Insulae, apartment blocks rising up to six storeys above shops – an urban form that would not look out of place in contemporary Europe.
“In the early 18th century, the author Daniel Defoe was amazed by the high-rise flats of Edinburgh – sometimes as tall as 12 storeys – teetering over the Royal Mile. ‘I believe, this may be said with truth,’ he wrote, ‘that in no city in the world so many people live in so little room as at Edinburgh.’
“But it was the invention of the lift that really allowed density to rise. By unlocking the third dimension, the skyscraper became possible. This led to the canyons of Manhattan – which even today with its huge amount of commercial space has a density of 26,000 people/sq km – and eventually to Hong Kong with its forests of 70-storey housing blocks crowded at the foot of the mountains.”
The report said:
“It’s not just about physical restrictions. People must find places to live, and when there is a strong economic force drawing people with few resources into a city with little regulation, then slums grow. From the Rookeries of old London, to 20th-century population explosions in favelas and barrios, economic pressure can force the poor into ultra-dense living conditions. This creates packed neighbourhoods often without political recognition and thus no recourse to protection from crime, drugs, disease, natural disaster, deprivation and lack of education.
“Kibera, a slum in Nairobi, is infamous for its horrendous poverty and its metal shacks built millimetres away from railway lines, while Dharavi in Mumbai has a reported density of over 200,000 people/sq km. Rocinha, the largest favela in Rio de Janeiro, has a density of 48,000 people/sq km and over the years has accumulated much of the infrastructure of the city down the hill, gaining new problems of rising living costs and the threat of gentrification.”
“Probably the densest urban environment humans have ever created was Kowloon Walled City, a block on the Hong Kong mainland which was demolished in the 1990s. This phenomenally dense cluster of 12-storey apartments around a tiny courtyard had alleyways like tunnels and Jumbo Jets swooping directly overhead into the old Kai Tak airport. When the famously lawless walled city was subject to a census in 1987 it had more than 30,000 people living there – a density of well over 1,000,000 people/sq km.”
Urbanization signal detected in evolution
A “clear signal” of urbanization has been identified in the evolution of organisms, which has implications for sustainability and human well-being.
In analysis of more than 1,600 cases around the globe, researchers said the changes could affect ecosystem services important to humans.
More than half of the world’s human populations now live in urban areas, and this proportion is set to grow.
The findings appear in the Proceedings of the National Academy of Sciences.
The study report said:
Humans challenge the phenotypic, genetic, and cultural makeup of species by affecting the fitness landscapes on which they evolve.
Recent studies show that cities might play a major role in contemporary evolution by accelerating phenotypic changes in wildlife including animals, plants, fungi, and other organisms.
The study presents evidence on the mechanisms linking urban development patterns to rapid evolutionary changes for species that play important functional roles in communities and ecosystems.
Through a metaanalysis of experimental and observational studies reporting more than 1,600 phenotypic changes in species across multiple regions, the scientists asked: whether we can discriminate an urban signature of phenotypic change beyond the established natural baselines and other anthropogenic signals. The scientists then assessed the relative impact of five types of urban disturbances including habitat modifications, biotic interactions, habitat heterogeneity, novel disturbances, and social interactions.
The study shows a clear urban signal; rates of phenotypic change are greater in urbanizing systems compared with natural and nonurban anthropogenic systems.
By explicitly linking urban development to traits that affect ecosystem function, the study can map potential ecoevolutionary implications of emerging patterns of urban agglomerations and uncover insights for maintaining key ecosystem functions upon which the sustainability of human well-being depends.
The scientists found a clear urban signal of phenotypic change, and greater phenotypic change in urbanizing systems compared to natural or non-urban anthropogenic systems.
Phenotypic change refers to change in an organism’s observable traits, such as it morphology, physiology, phenology, or behavior.
The changes in plants and animals included alterations in body sizes, shifts in behavioral patterns and adjustments in reproduction.
In a separate study published in 2008, researchers in France observed a rapid evolutionary change in a plant’s seed size in order for it to adapt to urban life.
They found that the seeds on Crepis sancta, otherwise known as hawksbeard, were larger on specimens that lived in urban areas, when compared with the seeds from the plants growing in rural settings.
As the plant’s seeds were dispersed by the wind, the researchers suggested that heavier seeds fared better because they would drop on to nearby soil, whereas the lighter seeds would be carried by the wind, resulting in them being deposited on concrete and tarmac, where it was impossible to germinate.
The speed in which this trait was expressed in the urban-dwelling plants surprised the researchers.
Changes that were observed in more than 1,600 studies were having an impact on evolution and that human activity, in the form of urbanization, would have a lasting legacy on life on Earth.
These findings add weight to the idea that the planet is now entering an Anthropocene epoch, a geological measurement of time in which humans are having a significant global impact on the Earth’s geology and ecosystems.
These changes are important is because they change ecosystem function, therefore they have implications for human well-being. These changes affect biodiversity, nutrient cycling, seed dispersal and water purification.
These changes meant that the alteration in the functions performed by the species, such as food production or the prevention of the spread of infectious diseases, would also be modified.
One of the scientists involved with the study “Global urban signatures of phenotypic change in animal and plant populations” said:
“We live on an urban planet already. This is a change that has implications for where we are heading in the future.
“We are changing the evolution of Earth and urbanization has a role, a significant role, in that.”
The scientists involved with the study report are Marina Alberti, Cristian Correa, John M. Marzluff, Andrew P. Hendry, Eric P. Palkovacs, Kiyoko M. Gotanda, Victoria M. Hunt, Travis M. Apgar, and Yuyu Zhou.
Uneven population distribution in developing countries
The report of the United Nations World Commission on Environment and Development, widely known as Brundtland Report, said in Chapter 2 (“Towards Sustainable Development”) (excerpts):
The goals of economic and social development must be defined in terms of sustainability in all countries.
Development involves a progressive transformation of economy and society. A development path that is sustainable in a physical sense could theoretically be pursued even in a rigid social and political setting. But physical sustainability cannot be secured unless development policies pay attention to such considerations as changes in access to resources and in the distribution of costs and benefits. Even the narrow notion of physical sustainability implies a concern for social equity between generations, a concern that must logically be extended to equity within each generation.
The essential needs of vast numbers of people in developing countries for food, clothing, shelter, jobs – are not being met, and beyond their basic needs these people have legitimate aspirations for an improved quality of life. A world in which poverty and inequity are endemic will always be prone to ecological and other crises. Sustainable development requires meeting the basic needs of all and extending to all the opportunity to satisfy their aspirations for a better life.
Sustainable development requires that societies meet human needs both by increasing productive potential and by ensuring equitable opportunities for all.
An expansion in numbers can increase the pressure on resources and slow the rise in living standards in areas where deprivation is widespread. Though the issue is not merely one of population size but of the distribution of resources, sustainable development can only be pursued if demographic developments are in harmony with the changing productive potential of the ecosystem.
A society may in many ways compromise its ability to meet the essential needs of its people in the future – by overexploiting resources, for example. The direction of technological developments may solve some immediate problems but lead to even greater ones. Large sections of the population may be marginalized by ill-considered development.
Growth has no set limits in terms of population or resource use beyond which lies ecological disaster. Different limits hold for the use of energy, materials, water, and land. Many of these will manifest themselves in the form of rising costs and diminishing returns, rather than in the form of any sudden loss of a resource base. The accumulation of knowledge and the development of technology can enhance the carrying capacity of the resource base. But ultimate limits there are, and sustainability requires that long before these are reached, the world must ensure equitable access to the constrained resource and reorient technological efforts to relieve the pressure.
Poverty, environmental degradation, and population growth are inextricably related and that none of these fundamental problems can be successfully addressed in isolation. We will succeed or fail together.
If economic power and the benefit of trade were more equally distributed, common interests would be generally recognized. But the gains from trade are unequally distributed, and patterns of trade in, say, sugar affect not merely a local sugar-producing sector, but the economies and ecologies of the many developing countries that depend heavily on this product.
When urban air quality deteriorates, the poor, in their more vulnerable areas, suffer more health damage than the rich, who usually live in more pristine neighbourhoods.
Critical objectives for environment and development policies that follow from the concept of sustainable development include: meeting essential needs for jobs, food, energy, water, and sanitation; and ensuring a sustainable level of population.
The sustainability of development is intimately linked to the dynamic: or population growth. The issue however, is not simply one of global population size. A child born in a country where levels or material and energy use are high place a greater burden on the Earth’s resources than a child born in a poorer country. A similar argument applies within countries. Nonetheless, sustainable development can be pursued more easily when population size is stabilized at a level consistent with the productive capacity of the ecosystem.
The greater part or global population increase will take place in developing countries, where the 1955 population of 3.7 billion may increase to 6.8 billion by 2025. The Third World does not have the option of migration to ‘new’ lands, and the time available for adjustment is much less than Industrial countries had. Hence the challenge now is to quickly lower population growth rates, especially in regions such as Africa, where these rates are increasing.
Population policies should be integrated with other economic and social development programs – female education, health care, and the expansion of the livelihood base of the poor.
Population growth in developing countries will remain unevenly distributed between rural and urban areas. UN projections suggest that by the first decade or the next century, the absolute size or rural populations in most developing countries will start-de-lining. Nearly 90 per cent of the increase in the developing world will take place in urban areas, the population or which in expected to rise from 1.15 billion in 1985 to 3.25 billion in 2025. The increase will be particularly marked in Africa and to a lesser extent, in Asia.
Developing-country cities are growing much faster than the capacity of authorities to cope. Shortages or housing, water, sanitation, and mass transit are widespread. A growing proportion of city-dwellers live in slums and shanty towns, many of them exposed to air and water pollution and to industrial and natural hazards. Further deterioration is likely, given that most urban growth will take place in the largest cities. Thus more manageable cities may be the principal gain from slower rates or population growth.
Urbanization is itself part or the development process. The challenge is to manage the process so as to avoid a severe deterioration in the quality of life. Thus the development of smaller urban centres needs to be encouraged to reduce pressures in large cities. Solving the impending urban crisis will require the promotion of self-help housing and urban service by and for the poor, and a more positive approach to the role or the informal sector, supported by sufficient funds for water supply, sanitation, and other services.
Pressure on resources increases when people lack alternatives. Development policies must widen people’s options for earning s sustainable livelihood, particularly for resource-poor households and in areas under ecological stress.