The dizzying pace of human migration to urban environments is expected to sweep up more than 68 percent of the world population by 2050, according to a new report. Prepared by the Population Division of the UN Department of Economic and Social Affairs, the study says 90 percent of the growth will be fueled by increased urbanization in Asia and Africa, with cites in China, Nigeria and India experiencing the greatest booms.

While the massive rise in urbanization underway in developing countries is reminiscent of the first wave that took place in Europe and North American between 1750 and 1950, its pace is unparalleled. About 4.2 billion people currently live in cities around the world, and an additional 2.5 billion are expected to be added over the next 30 years.

As Robert Muggah, research director of the Igarapé Institute in Rio de Janeiro, told Ensia earlier this year, this expected swell of people within such a small time frame paints a worrying picture.

"Many fast-growing cities urbanize before they industrialize," he said. "It took centuries for cities in the Global North to do this. In the south we are seeing a doubling of population in 25 years. Most cities [today] don’t have the infrastructure, employment base or productivity to manage this growth. You see a maze of informal settlements, completely overloaded infrastructure. Cities are generating a challenge on a resource level never seen before. The fastest-growing cities may be hit the hardest."

Here come the megacities

Tokyo, currently the world's largest megacity with more than 37 million inhabitants, is expected to be eclipsed by New Delhi by 2030. Tokyo, currently the world's largest megacity with more than 37 million inhabitants, is expected to be eclipsed by New Delhi by 2030. (Photo: Chris Battaglia/flickr)

According to the U.N., the world will host 43 megacities with populations of more than 10 million inhabitants by 2030. New Delhi is expected to overtake Tokyo as the world's largest city, with a population of 43.3 million by 2035. The rural population meanwhile, which has grown slowly since 1950, is expected to peak in the coming years and then decline to 3.1 billion by 2050.

The U.N. notes that the expected upward trend in urbanization highlights an urgent need for cities to embrace inclusive, sustainable growth strategies that address everything from housing to healthcare to energy and education.

"As the world continues to urbanize, sustainable development depends increasingly on the successful management of urban growth, especially in low-income and lower-middle-income countries where the pace of urbanization is projected to be the fastest," they state.

Opportunity at the expense of happiness?

Recent studies have found an increase in overall life satisfaction the further one moves away from urban environments. Recent studies have found an increase in overall life satisfaction the further you move away from urban environments. (Photo: Ken Douglas/flickr)

While cities are bastions of rich culture, innovation and economic opportunity, humanity's present and future love affair with them may erode our overall well-being.

A recent Canadian study found that people living in rural areas and small towns were significantly happier, with shorter commutes, tighter social circles, and less expensive housing all being major factors. The study backed up a previous American one, which found overall increasing levels of life satisfaction the more people moved from megacities to smaller urban environments and small towns.

The loss of a connection to nature, something all urban environments should aspire to correct, is also considered a defining factor in overall happiness.

"One of the things we’re recognizing is that, like other medicines, nature follows a dose curve," author Florence Williams told NatGeo last year. "A little bit of nature is helpful; a little more nature is even more helpful. If we think about how to access a little bit of nature in our daily lives, that’s a great start: houseplants, going for walks on streets with trees and, as you move further up the pyramid, making an effort maybe once a month to go to a nature preserve or park outside the city."

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

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