From Henry Kravis to Natalie Portman, vertical farming is suddenly hot

An A-list of Hollywood celebrities and Wall Street investors are scaling up vertical urban farming in a quest for big returns and climate action. In 1999, an environmental and health sciences professor at Columbia University challenged his graduate students to figure out how much food they could produce on rooftop gardens in New York City. The results were disappointing, producing only enough for about 1,000 people out of a population of millions. Undeterred, Professor Dickson Despommier continued to work with students to find better ways to grow crops in New…