"A city is more than a place in space. It is a drama in time." So wrote the urban planner Patrick Geddes at the start of the 20th century. Today, that drama has taken on new urgency and complexity. The world's cities have become the global stage for some of humanity's greatest challenges, calling on our collective ingenuity, investment, and commitment to solve.
The number of people living in the world's cities has more than quintupled since 1950. Already, there are more than 3.5 billion city dwellers worldwide, and that number is expected to surpass 6 billion by 2050.
Urbanization on such a large scale, however, is more than just a trend. It is a fundamental transformation in how people live and societies are structured. And while the rapid pace of urban migration reflects the incredible opportunities that modern cities make possible, it also adds to the urgency of two interrelated challenges: social isolation and environmental sustainability.
First, we know that people in cities often struggle with feelings of isolation and a lack of belonging.
Big crowds and busy streets do not always help to create a sense of connectedness; for many city residents, they actively contribute to feelings of alienation. Rapid urbanization is exacerbating this challenge as walkable spaces shrink, parking lots replace playgrounds, and high-rises eclipse neighborhoods--all of which make it increasingly difficult to maintain a healthy sense of community and belonging. New arrivals, especially immigrant populations who may not speak the language, can struggle to establish a sense of belonging amidst the crowd.
Second, as urban areas and populations continue to grow, I believe that cities may become the next environmental frontier.
From Burkina Faso to Bangladesh, we have already witnessed the effects of global climate change pushing rural residents to migrate to urban areas. Yet, climate change can have severe consequences for cities too, in the form of extreme weather events, rising sea-levels, and heat waves.
Meanwhile, as cities expand, the infrastructure needed to sustain new populations often cannot keep pace with demand. For that reason, unchecked urban growth can negatively impact human health and safety, gravely lowering the quality of life for city residents.
The impact of these dual challenges is becoming evident in cities around the world. In China, for example, residents of Shenzhen worried that rampant construction growth was creating a dangerous accumulation of debris. Their concerns were largely ignored until December 2015, when a massive landslide of dirt and waste destroyed more than 30 buildings, claiming dozens of lives. Also in December, the capital city of Beijing, which is being developed into a supercity larger than the country of Senegal, issued two unprecedented "red alerts" as a result of hazardous smog in the air.
Notably, the burdens of both social isolation and environmental degradation can weigh heavily on the most vulnerable members of urban populations. During his September 2015 visit to New York City, Pope Francis called attention to the "forces that push us into isolation," cautioning that "big cities also conceal the faces of all those people who don't appear to belong." It is these "second-class citizens"--including the poor, the elderly, and children--who are disproportionately at risk of diseases caused by air pollution and other environmental hazards.
The good news is that many of the solutions to these challenges are mutually reinforcing. Open spaces and public transportation, for example, promote social connectedness and are good for the environment too. By the same token, a sense of shared purpose and responsibility among city residents and officials is essential to support good environmental policies--which, in turn, can reduce the isolation of marginalized groups and individuals.
To provide healthy social and physical living environments, cities and stakeholders at every level need the tools to effectively measure their problems and progress. That is why the 2016 Environmental Performance Index is such an important resource. Launched in January at the World Economic Forum in Davos, Switzerland, the EPI measures the environmental performance of 180 countries across nine key areas, including air and water quality, wastewater treatment, and energy consumption. And as the EPI shows, many of these issues affect urban populations most acutely.
Looking ahead, understanding the specific impacts within specific cities and regions will be critical to cultivating increased awareness and action. In Chicago, for example, one recent study found a link between local air pollution and criminal activity. Could such a link exacerbate social isolation, if people are afraid to leave their homes? The 2016 EPI reveals that more than 3.5 billion people live in places with unsafe air quality. At stake may not just be human health, but the health of society itself.
Measuring and understanding these challenges at the urban scale is our best hope for success in improving the quality of people's lives in the places that most people live. The time is now to work together to find innovative solutions for combating isolation and promoting environmental sustainability in tandem.
And we must work together, for collective progress depends on collective action--summed up, as sustainable development champion Cherie Nursalim has described, in the Indonesian belief of Pancasila, or uniting in diversity. Only by joining as one human family can we make our cities places where every family can thrive. In the end, the urban condition is the human condition and we need to find ways to lift both.