Vertical farming’s success depends on the cheapest lightbulb

Vertical farming’s success depends on the cheapest lightbulb

Abu Dhabi's giant Yas Mall isn't the most obvious location for embracing nature. The sprawling complex, which houses a 20-screen cinema, leads to a Ferrari-themed amusement park.

At its heart is the Carrefour hypermarket. There's no natural light or soil, yet floor-to-ceiling shelves offer shoppers herbs and microgreens grown right in the store. The fresh produce is a rare sight in the United Arab Emirates, which is almost all desert and imports 80 per cent of its food. It's marketed as a healthy way for customers to reduce the carbon emissions that would be generated transporting their groceries.

More than a decade ago, microbiologist Dickson Despommier floated the idea that nations with little arable land like the UAE could become self-reliant by growing food in skyscrapers with perfectly optimised artificial light and heat. He called it vertical farming and argued that it could reduce world hunger and restore forests depleted by commercialised agriculture. It would also eliminate planet-warming emissions caused by plowing fields, weeding and harvesting, as well as transportation.

In the years since, millions of dollars have poured into companies trying to make Despommier's idea a reality. Agriculture and forestry account for about a quarter of the world's greenhouse gases, while