It's a global climate solution — if it can get past conspiracy theories and NIMBYs

PARIS — In the 11th arrondissement, a middle-to-working class neighborhood in the east of Paris, if you walk out your front door, you can arrive at a preschool in one minute. A bookstore in three minutes. A cheese store in four minutes. Baguette for that cheese? Bakery's across the street.

Grocery store and pharmacy, five minutes. Parks, restaurants, metro stops, a hospital: all within a 15-minute walk. I know this because I used to live there, on a tiny cobblestone street with buildings covered in vines.

This is a 15-minute city, says Carlos Moreno, a professor at University of Paris 1 Panthéon-Sorbonne, who met me on the banks of the Seine River. Moreno says that in a 15-minute city, a person can access key things in their life — work, food, schools and recreation — within a short walk, bike, or transit ride of their home.

My former Paris street and much of the neighborhood were built in this dense way more than 150 years ago. But this old idea of areas with many amenities close by has now evolved into an urban planning model gaining popularity with politicians around the world. Moreno says that's because it not only improves quality of life, but 15-minute cities can also reduce cars' planet-warming greenhouse gases. Transportation accounts for about 20% of global energy-related carbon dioxide pollution, with cars making up almost 10%, according to the International Energy Agency.

In recent years, Moreno has been helping mayors put this idea to use, particularly the mayor of Paris, Anne Hidalgo. Paris is converting old military buildings and old parking structures into mixed-use buildings with apartments, retail and office