Art Wager, Getty Images Tall building projects have expanded over the past several decades to include more disciplines and surrounding infrastructure, a trend experts say must continue in order to meet the growing demands of population growth, climate resilience, and sustainability on cities.
An inaugural vertical urbanism index, compiled by the Council on Tall Buildings and Urban Habitat, looks to foster that expansion by providing city-level data and by inviting more stakeholders to the tall building discussion.
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“I think everybody understands that, decades ago, the success of buildings – not only tall, but mainly tall – was more in innovation and the kind of iconic component in how they raised the profile of cities,” said CTBUH CEO Javier Quintana de Uña. In the past, he added, fewer disciplines were involved in putting up a tall building. “But as cities evolved, the success of architecture in general, but very specifically tall buildings, is the way they connect to infrastructure, the way they carry community, the way they land on street level. … The (CTBUH) is in the quest of kind of opening the skyscraper club to many other people.”
David Farnsworth, the Americas property leader at sustainable development consultancy firm Arup, agrees, saying the ground plane of a tall building has become its most important component. With the need for garage access and multiple lobbies in a limited space, it has also become the most constrained.
“Certain architects have been pushing the way that buildings interact with the public realm in a more mature and thoughtful way,” Farnsworth said. “We’re seeing more and more (that) the most successful buildings also have a significant public-facing component to that ground-floor plane.”
The CTBUH index looked at 40 urban agglomerations across six continents that were selected based on the number of completed, under-construction, or proposed buildings exceeding 100 meters high in the city areas. The availability of city data and geographic diversity also served as selection factors.
Livability and population
While livability increases with population density in cities, it does so only up to a point, according to a report on the index. After density crosses a certain threshold, livability begins to decrease.
To quantify livability, cities were measured along social indicators, such as education, health care, and affordable housing; environmental indicators, such as green space, air quality, and water quality; and economic indicators that analyzed the median resident’s ability to afford basic necessities.
Farnsworth attributes the reversal to the balance between the benefits and drawbacks of living close to other people.
“I think there's a certain level of density that fosters the urban realm,” Farnsworth said. “You get enough density that makes it viable to have walkable neighborhoods, enough population to support good restaurants and bars and other kinds of cultural attractions.” But beyond a certain point, it becomes “a rat race to find a seat on a subway car, or you're paying an exorbitant amount of your income on living expenses.”
Council on Tall Buildings and Urban Habitat
One of the main purposes of the index was to spotlight relationships such as this one, says Quintana de Uña, so that conversations can start around the data. He added that it’s clear that as density grows, infrastructure such as transportation and education often grows with it, lifting the livability of cities.
“However, if you go too much and you cannot provide those other services, that will make something balanced start to fall apart,” Quintana de Uña said. “It's easier to build a taller building or a cluster of taller buildings than bringing the whole infrastructure at the same time.”
With livability in mind, architects and engineers are bringing in occupant experience earlier in the design process for tall buildings.
Farnsworth said that, while the physics governing tall building design hasn’t changed over the years, the capabilities to test, analyze, and demonstrate the performative aspects of a tower, such as its wind, seismic, or acoustic properties, have progressed significantly. The Arup SoundLab and Arup Motion Platform, for example, provide environments that allow clients to hear, feel, and see for themselves things like building sway, noise propagation from outside to inside, and the effects of different floor constructions and finishes.
“We have a much better ability to predict what's going to happen and tools that help our clients experience and understand what those predicted responses will feel like, so that more informed decisions can be made,” Farnsworth said.
Tall building count and population
The number of skyscrapers, too, does not always correlate with population density. For 71% of the cities studied, tall buildings clustered in city areas with relatively lower density, according to the report.
The effect is largely a result of geography but also of culture, says Quintana de Uña. Compared with Europe or Asia, North America boasts an abundance of flat, buildable land. Planners in North America have zoned cities into distinct business and residential districts surrounded by the urban sprawl of satellite towns and suburbs. These cities tend to house people away from the tall buildings.
“(In America), you can keep going and going,” Quintana de Uña said. “It’s no one’s fault. In fact, it has become kind of the American dream: I want my house with a garden.”
In contrast, European and Asian cities have responded to geographical limitations with more mixed-use districts.
This disparity across continents became more pronounced during the COVID-19 pandemic, says Quintana de Uña. Cities on the American West Coast, such as Seattle; Portland, Oregon; and San Francisco, continue to struggle in their recovery from the work-from-home culture that lockdowns introduced.
“I went through COVID in London, where apartments and houses are tiny,” he said. “The people were dying to go back to the office after COVID, whereas here (in the United States), that has not happened. … American people, they have their houses that are big. They've been able to accommodate offices in their houses, so they don't need to go back to the tower.”
American downtowns and tall buildings are shifting toward more mixed uses, with more emphasis on residential purposes, to avoid becoming deserted.
This year and beyond
As of the beginning of the year, 41 countries had at least one completed skyscraper over 200 meters tall, according to CTBUH’s 2025 Trends & Forecasts report. China continues to lead in tall building activity, housing 52% of the world’s over-200-meter buildings, according to the report.
Last year saw the completion of the 394-meter-tall Iconic Tower in Cairo, the tallest completion last year and the first building in Africa to exceed 300 meters high. The 366-meter Ciel Tower in Dubai, United Arab Emirates, and the 352-meter Central Bank of the Republic of Turkey in Istanbul joined as the second and third highest of last year’s 130 completions that exceeded 200 meters.
The forecast also noted that the world’s first 1,000-meter building, the Jeddah Tower in Jeddah, Saudi Arabia, resumed construction late last year.
Based on a record number of stalled projects, the CTBUH expects the worldwide completion rate to continue decreasing this year off the peak seen in 2023, estimating 135 projects over 200 meters tall to complete in 2025, of which up to 20 will exceed 300 meters tall.
