Sourced from the World Economic Forum
High above the streets of New York, more than 36 tonnes of organic vegetables are grown every year. And the farms that produce them aren’t just feeding residents – they’re helping to stop sewage polluting the city’s rivers too.
Covering a total of 2.3 hectares (5.6 acres), the farms sit on top of three historic industrial buildings. Their soil is just 25 cm (10 inches) deep, but it absorbs millions of litres of rainfall each year – water that would otherwise flush straight into the city’s drains.
New York has long had a problem with what is known as Combined Sewer Overflow, where rainwater inundates water treatment plants causing the sewers to overflow directly into the Hudson and East River.
The city has made progress in recent decades, spending $45 billion since the 1980s on wastewater treatment to reduce discharges into waterways. But with more than 70% of its area paved and upwards of 8 million residents, the problem still occurs when it rains heavily.
Brooklyn Grange, which operates the three rooftop sites, built its first farm in 2010. It broke even in its first year, moved into profit two years later and now employs 20 full-time and 60 seasonal staff.
Its founders believe commercial urban agriculture can help cities become cleaner and greener. And they measure their success against a “triple bottom line” – profit, the environment and impact on people.