If you’re like most people, you live in a city. More than half the world’s  population now lives in cities, and that figure will go to about two-thirds  of humanity by the year 2050. Cities are getting bigger.

Rapid urbanization is resulting in a growing number of slum dwellers, inadequate and overburdened infrastructure and services (such as waste collection and water and sanitation systems, roads and transport), worsening air pollution and unplanned urban sprawl. 

In 1990 there  were ten “mega-cities” with 10 million inhabitants or more. The world is becoming increasingly urbanized. Since 2007, more than half the world’s population has been living in cities, and that share is projected to rise to 60 per cent by 2030. In 2014, there  were 28 mega-cities, home to 453 million people. Incredible, huh? A lot  of people love cities; they’re centers of culture and business and life.

Cities and metropolitan areas are powerhouses of economic growth—contributing about 60 per cent of global GDP. However, they also account for about 70 per cent of global carbon emissions and over 60 per cent of resource use. 

The  thing is, they’re also often centers of extreme poverty. To make cities  sustainable for all, we can create good, affordable public housing. We  can upgrade slum settlements. We can invest in public transport, create  green spaces, and get a broader range of people involved in urban  planning decisions. That way, we can keep the things we love about  cities, and change the things we don’t.