Since 2007 over 50% of the world’s population can be found in cities and UN demographers predict that within 2050 this figure will reach 70%. The changes expected are enormous not only due to the number of people involved but also for the scenarios envisioned.

Nico Zardo

If the inhabitants of the earth maintained their current consumption habits, humanity would need 1.5 planets like the Earth to be able to have the necessary resources. This fact, contained in the WWF’s Living Planet Report 2014, helps us understand how important it is to change attitude when speaking about sustainability. A commitment that concerns all of us: institutions, in their role as governing and legislating bodies; companies, called to review their production processes and spur more responsible consumption attitudes; individual citizens, who can deeply affect the scenario with their behaviors and their choices both on a personal level and as members of their relative communities.
A large portion of the urban development forecasted will take place in developing countries that will have to meet several challenges in order to satisfy the new needs regarding housing, infrastructures, transportation, energy and employment, as well as basic services such as education and health care. Thirty-seven percent of the world’s urban population growth between 2014 and 2050 will involve India, China and Nigeria. In 2050, India’s urban population is forecasted to reach 404 million people, China’s 292 million and Nigeria’s 212 million.


IN 2014, 28 MEGACITIES HAVING OVER 10 MILLION INHABITANTS WERE CENSUSED: sixteen are in Asia, four in Latin America, three in Africa and in Europe and two in North America. Within 2030, the world is expected to have 41 megacities with 10 million or more people.
Tokyo remains the largest city in the world with 38 million inhabitants, followed by Delhi with 25 million, Shanghai with 23 million, and then Mexico City, Mumbai and São Paulo, each with about 21 million people. Osaka has just over 20 million, followed by Beijing with slightly below 20 million. The area of New York-Newark and Cairo complete the first ten most populated urban areas with about 18.5 million inhabitants each.
Small cities are numerous and growing fast. Almost half of the 3.9 billion inhabitants of cities worldwide lives in relatively small settlements with less than 500,000 inhabitants, while only about one out of eight lives in 28 megacities with 10 million inhabitants or more.
So considering the strong migratory flow from rural areas to the city, facing a sustainable urbanization is the key for the success of their development and the issues tied to health and hygiene that occupy a primary importance.


AIR AND CLIMATE CHANGES. Today cities host over half the world’s population but consume two-thirds of the energy and produce over 70% of the CO2 emissions responsible for global warming. The effects on the health of the citizens are sadly known and the diagnosis has been clear for years.
The recipe by UN experts presented in Copenhagen in November 2014 speaks clearly: “Our emissions should drop by 40 to 70 percent globally between 2010 and 2050, falling to zero or below by 2100”.
Almost half of the cities are already starting to measure themselves up against the effects of climate change and soon, practically all of them will have to do so, mainly because over 90% of the urban areas rises along coastlines and in a few years they will be forced to deal with the rise in sea level and the intensification of extreme atmospheric events. The Asian tsunami of 2004 and hurricanes Katrina in 2005 and Sandy in 2012 rendered climate change along coastal cities dramatically visible.
Cities in advanced nations will have to adopt new technologies to mitigate the effects of warehouse gases, and invest in the reorganization of transportation systems and initiatives directed at a sustainable system of life.
For cities in developing areas, a determining factor will be to adopt planning choices aligned with technologies that tend to reduce the energy consumption of buildings and means of transportation, making infrastructures more sustainable.


WATER AND RENEWABLE RESOURCES. Ninety-seven percent of all water on our planet is salt water. Just one percent is part of the renewable fraction thanks to the hydrogeological cycle. The remainder is trapped inside icebergs, at the Poles on in groundwater. And we know that the distribution of the precious liquid on our planet is not homogeneous: some countries have an abundance of water while in others is it lacking. The megacities already present or taking shape in Asia, Latin America and Africa will have to face a great challenge. In most developing countries, urban growth is inextricably linked to the expansion of slums and poverty; in 2000, almost one-third of the inhabitants of suburban areas lived in shantytowns.
Since the city’s infrastructures cannot keep pace with the massive urban growth, many people are left with no possibility of access to drinkable water and to sanitation.


- In Mexico City, excessive exploitation of groundwater has contributed to continuous subsidence (5-40 cm per year), increasing the probability of flooding. Dependence on high altitude reserves for water supply has led to social and environmental conflicts with the communities of the donor basins as well as to high energy costs to transport water from altitudes above 1000 meters and for a distance of 150 kilometers.
- The pollution levels of the rivers in Buenos Aires are so high that they can be considered “open sewers”. The Riachuelo, one of the most polluted rivers in the world, flows through the Argentinian capital in an area inhabited prevalently by a low-income population, where cases of intestinal infections - often fatal - are registered with a higher-than-average frequency.
- Sixty percent of the inhabitants of Nairobi, Kenya, live in shantytowns with insufficient access to drinkable water: they are forced to buy it from private distributors at high prices. The lack of sanitation and waste treatment is the cause of severe problems for the health of the local population, but also of the pollution of rivers.
- Over 50% of the population of Karachi, Pakistan, lives in slums and most of them experience great shortage of water as well as the lack of a suitable sewerage system. Eighty percent of untreated wastewater is discharged into the Arabian Sea and about 3,000 people, mainly children, die each year in the city because they consume contaminated water.
- Kolkata, India, has problems of fecal contamination of municipality waters and of arsenic pollution of groundwater. The water authority has great difficulties in maintaining the efficiency of the water distribution system because - since it is free of charge - management problems exist.
- The abundant presence of water is not sufficient to meet the growing demands of the 23 million inhabitants of Shanghai. Polluted rivers and the saline intrusion of the Yangtze, with further worsening brought by climate change, are the main threats to the safety of the water.
These situations are illustrative of problems existing in many parts of the world and underscore, to different degrees, how water management is a foundational issue for the civilized development of cities. Their sustainability goes well beyond the engineering aspect of water flow management and requires the integration of different aspects such as awareness for reducing consumption, proper maintenance of the networks, reusing rainwater and wastewater, integrated management of river basins, payment for environmental services and adaptation to climate changes.


FOOD. According to the FAO, each year 1.3 billion tons of food are wasted, between fruit, vegetables and other products of the earth that end up in trash bins often before they even arrive into people’s homes or are thrown away by the latter because they have reached their expiry date.
Just like drinkable water, food, too, is present in non-homogeneous fashion throughout our planet: indeed, for the 900 million people suffering from starvation, there are 1.4 billion people who have overweight problems (UN, September 2014). And 80% of the people who do not have enough food live in the country and work to produce food for the inhabitants of those cities that are becoming increasingly large. This is a strong spur for moving to the city.


THE “PARADOXICAL MECHANISM” could lie in the fact that there are about a dozen major companies (with hundreds of brands) controlling 70% of the planet’s food industry, and in order to obtain high-performing balance sheets, they must fully exploit both the land and those who work to produce the raw materials.
Also as far as food is concerned, industrialization leads to a simplification in the types of foods, hence to a loss of variety and often the final product must accept the presence of ingredients that are not always qualified, in obedience to laws of strict market economy. Gratification for the consumer is entrusted to the image on the package and to a persuasive advert campaign. Artfully induced desires for food, little attention to food habits lead many citizens to those overweight situations that are often connected to illnesses, even fatal ones.


RECENT RESEARCH BY THE ROCKEFELLER FOUNDATION, “TRANSFORMING CITIES, VISIONS OF A BETTER FUTURE”, conducted with the collaboration of mayors, architects, bankers, slum activists and entrepreneurs, examined the critical points that the great transformation of the cities could entail.
- The first problem concerns the ability to plan those changes that in a situation of widespread economic difficulties experienced by most urban administrations and of political instability typical of many governments, will allow making only short-term decisions and provisions, leaving long-term problems unattended to. In a scenario of rapid urbanization, these difficulties will per force result in a low quality of services and a strongly compromised livability of the cities.
- Climate changes - after the examples of the terrible experiences of the Asian tsunami, the increasingly violent hurricanes, flooding, droughts and heat waves
- will put a heavy strain on coastal cities in particular.
The effects will have an impact on infrastructures, will cause damages due to the interruption of regular activities and augment the exclusion of the poorer citizens living in increasingly vulnerable areas.
- In fast-growing metropolises where integration times are short, the division between wealthy and poor districts will be marked by a different quality of the services provided. The situation will fuel protests, disorders and social friction. This vicious cycle will diminish the quality of public services such as transportation, water and energy supply, and waste collection. Some examples of these mechanisms have been witnessed in different forms in India, in Brazil and in the suburbs of Paris.
- Good planning is certainly important for an eventual improvement in services, and many are the expectations coming from the consistent increment in data collection, whose processing may allow refining the results. The major and easiest interactivity could favor a more direct communication, broader and in real time, it could supply indications to the governing bodies, enhance entrepreneurial opportunities and make social protests more participatory. By contrast, negative effects will stem from an undesired use of the data.
- An increase in social protests can be envisioned, and these can originate from dissatisfaction and frustration, low quality of the infrastructures, insecurity and instability, local movements. Spread through social media, they could benefit from reactions useful in giving rise to new forms of governance.



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