This article is part of our Design special section about innovative surfaces in architecture, interiors and products.
In the lineup of climate villains, architecture towers above many. The building and construction industries account for some 37 percent of worldwide carbon dioxide emissions, according to the United Nations Environment Program. Three of the most commonly used building materials — concrete, steel and aluminum — generate nearly a quarter of all carbon output.
But there is progress. The use of renewable organic materials like wood, hemp and bamboo is expanding. Carbon-absorbing plants and trees are more widely integrated into architectural design. And even concrete is losing its stigma with the development of low-carbon varieties.
Sustainability-minded architects are adopting these materials in buildings that not only are more environmentally sensitive but also look and feel different from modernism’s concrete and steel boxes.
One of the most potent symbols of the green building revolution — in the public imagination, at least — is the plant-covered high-rise. Building designs draped in vegetation can be found in the portfolios of international architects like Jean Nouvel, Norman Foster, Lina Ghotmeh, Thomas Heatherwick and Kengo Kuma, to name but a few.
No one, however, has done more to promote this type of structure than the Milanese architect Stefano Boeri, who calls his creations Vertical Forests.
The original Vertical Forest — a pair of residential towers with facades incorporating about 800 trees, 5,000 shrubs and 15,000 plants — opened in Milan in 2014. Mr. Boeri has since completed about a dozen more examples, most recently in Huanggang, China, and the Dutch city of Eindhoven.
“What we have done is to use plants, not as ornament,” but as “a kind of biological skin,” Mr. Boeri said. The greenery shades and cools, regulates humidity and absorbs carbon dioxide and pollution. It also serves as a habitat for birds and insects and creates a direct, immediate connection between residents and nature.
The buildings “are always evolving and changing with the seasons,” said Mr. Boeri, who has future projects — some, entire villages — in various stages of development in locations including Cairo, Dubai and the Mexican resort town of Cancún.
Some critics have dismissed the Vertical Forest concept as green washing or eco-bling, arguing that the environmental benefits are negated by the carbon-intensive concrete and steel required to sustain the weight of the trees and plants. Mr. Boeri said studies by the engineering firm Arup found only a 1 percent increase in carbon dioxide emissions related to the construction of the Vertical Forest buildings. He added that his firm now typically used prefabricated concrete panels and that it was looking at building with wood, where appropriate, to reduce the carbon footprint.
Mr. Boeri acknowledges the limited environmental impact of single buildings but emphasized the importance of linking “biodiversity hot spots with a network of other green systems.” He imagines that in the future there could be forest cities “for sure.”
One metropolis taking steps in that direction is Singapore. Policies aimed at bringing nature into Singapore’s urban center have produced a cityscape punctuated by buildings that incorporate extensive greenery, including several by the local firm WOHA.
Among WOHA’s best-known designs are the recently completed Pan Pacific Orchard hotel, with its expansive garden terraces overflowing with plantings, and the Oasia Hotel Downtown, a 30-story tower enveloped by a red-mesh lattice interwoven with nearly two dozen species of creeping vines.
“The permeable living facade is part of the passive strategies we implemented to cool the building, lower energy consumption and create a relaxing biocentric space,” said Wong Mun Summ, a co-founder of WOHA. Studies have shown the exterior to be up to 68 degrees Fahrenheit cooler than nearby glass-walled structures, he said. Scaled up sufficiently, infusions of greenery could help repair the so-called urban heat islands created by expanses of asphalt, concrete, glass and steel.
The heat-island effect is a common problem in Asia’s megacities, where rapid development has obliterated many traces of nature. In Chengdu, China, which is now adding park spaces and encouraging urban greenery, Winy Maas, a founding partner of MVRDV in Rotterdam, is working on a 500-foot-high office tower with terraced gardens that cascade from a forested rooftop all the way to the ground.
“This is one of the first tall towers that has outside, walkable and interconnected space,” he said of the design, which includes a sculptural enclosure of metal mesh around the plantings to soften potentially damaging rains and winds. “At 150 meters high, the wind can dry out or kill them.”
Carlo Ratti, an Italian architect and the director of the Senseable City Lab at Massachusetts Institute of Technology, who has been picked to curate the Venice Architecture Biennale in 2025, is taking the greenery-clad high-rise in another direction. A couple of years ago, he unveiled a proposal for what he described as the world’s first “farmscraper,” in Shenzhen, China.
Dubbed the Jian Mu Tower, the 51-story building will be wrapped in a vertical hydroponic farm. Mr. Ratti has estimated his plan could yield enough produce annually to feed 40,000 people. His studio in Turin is working on prototype modules for the facade.
“At this critical moment, what we architects do matters more than ever,” Mr. Ratti said. “Every kilowatt-hour of solar power, every unit of zero-carbon housing and every calorie of sustainably sourced vegetables will be multiplied across history.”
Another tool for achieving zero-carbon buildings is one of the oldest and most common construction materials: wood. Valued for sequestering carbon dioxide and keeping it out of the atmosphere for decades, if not centuries, wood is now widely engineered into components of so-called mass timber, made with compressed, fire-resistant layers.
Among the timber buildings completed by the New York-based Bjarke Ingels Group, also known as BIG, is a new production facility for the Norwegian furniture company Vestre — “the most environmentally friendly factory in the world,” as Mr. Ingels, who is Danish, described it — in a forest near Magnor, Norway.
The star-shape building is topped with a green roof and solar panels that enhance its energy efficiency. “It’s a pretty striking factory to work in because of the warmth and texture of all the timber,” the architect said. He noted that the locally sourced wood even had an appealing smell.
Jeanne Gang is another architect with an affinity for wood. Her Chicago-based firm, Studio Gang, just completed an academic building and student housing for Kresge College in Santa Cruz, Calif. The gently curling timber-frame residential structures tuck into the densely forested site, their textured wood exteriors echoing the surrounding redwood trees. Ms. Gang described the material choices as “an ecological and poetic response to Kresge’s stunning environment.”
An equally evocative effect, in a very different context, is achieved in the new terminal for Kempegowda International Airport, in Bangalore, India, designed by Skidmore, Owings & Merrill, or SOM, based in Chicago. Conceived as “a model for sustainable development but also as a new experience around connecting to nature,” said the SOM principal Peter Lefkovits, the terminal is notable for its use of engineered bamboo, which clads the columns and is layered in latticed expanses across the ceiling. The design also incorporates hanging plants, lush walls of greenery and water features.
“The idea was to create a building that felt almost like a garden pavilion, with the openness and the qualities of filtered light,” Mr. Lefkovits said. This was the first time his 88-year-old company had used bamboo, a highly sustainable and renewable material because of its fast growth.
Architects are also turning to other natural, carbon-sequestering materials, like hemp, flax and seaweed. Henning Larsen, an international firm based in Copenhagen, recently used reeds to create its first-ever thatched facade, for a new primary school in southern Denmark.
The choice of thatching, which gives the building’s exterior a slightly shaggy, organic texture, was inspired by the local tradition of using wheat as facade cladding, said Jakob Stromann-Andersen, who leads Henning Larsen’s sustainability and innovation team. Everything about the horseshoe-shape building’s design, he added, was intended to “reinforce connections between the classroom and nature,” including a walkable green roof that slopes down and merges with the landscape at either end.
Organic fibers are also being incorporated into composites like hempcrete or mixed into bioresin panels that are durable enough for building facades. These types of materials are seen as essential in the race toward more sustainable buildings, as are recycled-content bricks and low-carbon concrete, both of which are coming into wider use. Researchers are also experimenting with adding carbon-absorbing algae to concrete to achieve mixtures with net-zero or even negative emissions.
“We cannot simply rely on natural materials, because there just isn’t enough timber and bamboo to build the whole stock of buildings we need,” said Yasemin Kologlu, who leads SOM’s Climate Action Group. “We can’t continue to build the way we are, but there’s not one silver bullet. It needs to be a culmination of maybe more than 30 different strategies for us to get there.”
