Source: BBC

Sometimes it’s difficult to fathom that the world could actually become even more crowded than it is today – especially when elbowing through a teeming Delhi market, hustling across a frenetic Tokyo street crossing or sharing breathing space with sweaty strangers crammed into a London Tube train. Yet our claustrophobia-inducing numbers are only set to grow.

While it is impossible to precisely predict population levels for the coming decades, researchers are certain of one thing: the world is going to become an increasingly crowded place. New estimates issued by the United Nations in July predict that, by 2030, our current 7.3 billion will have increased to 8.4 billion. That figure will rise to 9.7 billion by 2050, and to a mind-boggling 11.2 billion by 2100.

World population could rise to a mind-boggling 11.2 billion by 2100

Yet even today, it’s difficult enough to get away from one another. Drive a few hours outside of New York City or San Francisco, into the Catskill Mountains or Point Reyes National Seashore, and you’ll find crowds of city-dwellers clogging trails and beaches. Even more remote and supposedly idyllic spaces are feeling the crush, too. Backcountry permits for the Grand Tetons in Wyoming sell out months in advance, while Arches National park in Utah had toshut down for several hours last May due to a traffic gridlock.

Is bustling Tokyo about to get busier? (Credit: Thinkstock)

For those who can afford the luxury of occasionally escaping other members of our own species, doing so often requires getting on a plane and travelling to increasingly far-fetched locales. Yet humanity’s footprint extends even to the most seemingly isolated of places: you’ll find nomadic herders in Mongolia’s Gobi desert, Berbers in the Sahara and camps of scientists in Antarctica.

This begs the question: as the world becomes even more crowded, will it become practically impossible to find a patch of land free from human settlement or presence? Will we eventually overtake all remaining habitable space?

The London Tube carries 1.2 billion passengers per year (Credit: Getty Images)

Virtually all population growth between now and the end of the century will be in cities – Joel Cohen, population expert

Taking a stab at answering these questions requires examining what we know about where people will likely base themselves in the future, and what life will be like then. For starters, experts predict that – reflecting current trends – an increasing number of us will live out our lives in cities. As agriculture becomes more efficient, people abandon jobs in that shrinking and difficult sector and instead take up ones in urban manufacturing or service. This has been going on for some decades. In 1930, just 30% of the world’s population lived in cities, compared to about 55% today. By 2050, however, about two-thirds will be based in urban areas.

“Virtually all population growth between now and the end of the century will be in cities,” says Joel Cohen, head of the Laboratory of Populations at Rockefeller University and Columbia University, and author of a book called How many people can the Earth support? “It boils down to more than one million additional people living in cities every five to six days from now until 2100.”