2014 was a groundbreaking year for vertical greenery.
The award-winning One Central Park building in Sydney unveiled its 116-metre vertical garden and expansive green public space, while over in Milan, Italy, architect Stefano Boeri finally realised his Bosco Verticale project, which houses 900 trees and more than 2,000 plants.
Architects and developers continue to inject greenery into high-rise buildings as the concept becomes far more common.
Beyond adding greenery to balconies, roof terraces or on the walls of skyscrapers, however, there is also a trend toward using building surfaces for urban agriculture as rapid urbanisation creates demand for affordable inner-city housing and accessible food.
A 2014 United Nations report foresees an additional 2.5 billion people (66 per cent of the population) moving into urban areas by 2050. With this comes the opportunity to produce food in the heart of these urban areas through vertical farming.
Microbiologist Dickson Despommier Ph.D, who pioneered vertical farming and authored The Vertical Farm: Feeding the World in the 21st Century, believes the only way for urban farming is up with horizontal land becoming more scarce and prone to climate change conditions.
"An estimated 109 hectares of new land (about 20% more land than is represented by the country of Brazil) will be needed to grow enough food to feed (people), if traditional farming practices continue as they are practiced today," Despommier said on his website.
One impressive example of vertical farming is the rice terrace skyscraper, a project that was shortlisted for the World Architecture Festival.
Mexican architecture firm Cachoua Torres Camilletti designed the Arcology Skyscraper, which redefines the world of glass high-rises.
The project features two organically shaped towers designed to sit amongst the already thousands of high rise buildings in Hong Kong. Visually, it is designed to reflect the rice cultivation found in Hong Kong's mountainous regions.
“Rice terraces have an important semiotic and symbolic significance in a culture such as China, and they are in the end brought up by the need to sow seed vertically,” the architects said.
The two structures are made up of real rice terraces, including a green wall. There is a rice paddy on one rooftop and and a helipad on the other.
The structure also features transparent bridges that connect the towers, with the architects suggesting one tower could be used for residential purposes and the other used for farming and working.
The building is also clad in algae, rainwater is collected and dispersed, and solar panels are also present on the outside of the building.
Another food cultivation prototype that has received global attention came from Aprilli Design Studio, which created a building that visually reflects a tree, including root, trunk, branches and leaf structures.
The tree is proposed to sit at for a site located in downtown Seoul, adjacent to the Cheonggyecheon stream in a heavily populated dense urban area within the central business district.
"Through lifting the main food production field high up in the air, the vegetation gains more exposure toward the natural sunlight and fresh air while the ground level becomes more freed up with nicely shaded open spaces which could be enjoyed by the public," the studio firm said.
"The bio mimicry of the tree form gives many structural and environmental advantages to form a light weight efficient space frame which could host diverse farming activities."
Another noteworthy project is OVA's Hive-Inn City Farm. The project is a modular farming structure featuring containers stacked to build a tower. Designed as an ecosystem, each unit has the ability to produce food, harvest energy and recycle waste and water.
Hive-Inn is proposed for downtown Manhattan as a means of bringing food cultivation into urban neighbourhoods.
OVA is currently looking for partners to invest in the project, stating that it is commercially viable with each shipping container available for purchase or rent by organic brands, restaurants and local education facilities.
Despite these innovative ideas, while urban farming continues to rise in low-rise buildings, it has yet to catch on fully in skyscrapers. Soil isn't an issue due to the opportunity for hydroponic growth but energy usage is a concern with plants requiring ample light for photosynthesis.
Despommier believes architects are a little premature with current concepts for skyscraper-based urban agriculture, but remains optimistic the practice will become a reality.
"While that’s the goal, we’re not there yet," he told told Edible Manhattan earlier this year. "Right now the world’s tallest vertical farm, in Chicago, is just three stories high. Skyscrapers are the end-game. But you’d be stupid to try them now — you’d lose your shirt.”