If you thought the world was crowded now, just wait. According to the United Nations latest projections of world population growth, released in June, the planet will add another 2 billion people over the next 30 years. By 2055, the global population will be teetering on the brink of 10 billion. By 2100, well be looking at 10.9 billion humans an increase of more than 3 billion people, roughly 40% growth over present-day levels.

To sustain 3 billion new lives, food and energy production will need to increase dramatically. Demand for freshwater will spike. And the world is already in the middle of a mass biodiversity extinction crisis. Essentially, in the coming years, were going to need to do a lot more with a lot less.

And where will all these people live? Most of them are likely to end up crammed together in increasingly populous cities. (The U.N. predicts the world will have 10 new megacities by 2030 .) And some researchers argue thats exactly where they should be.

People tend to picture cities, particularly in the developing world, as urban wastelands belching out pollution, breeding sickness, promoting endless consumption and driving population increases. But cities also have a huge potential for getting us out of the very mess theyve helped get us into, according to some researchers. Well-designed cities, with dense housing and efficient mass transit can reduce energy use and emissions per person, and the opportunities they provide for women puts the lid on population growth, ultimately reducing the immense strain humans are putting on nature.

Urbanization has been, on the whole, fairly misunderstood, said Joe Walston, senior vice president at the Wildlife Conservation Society.

Walston and his colleagues looked at how urbanization can be a win for the conservation of biodiversity, in a 2018 paper published in BioScience. The world is approaching a tipping point, they argued, writing that the very trends that have resulted in unprecedented destruction of the environment are now creating the necessary conditions for a possible renaissance of nature.