The context is important with regard to tall buildings. In a place like Hong Kong, which encourages skyscrapers, the government owns the land and can gain high bids from developers by allowing what I call “vertical-density” development. Projects such as International Commerce Centre by Kohn Pedersen Fox [page 142] are part of a centralized urban-planning and development scheme that includes transit hubs, offices, housing, and retail.

In other cities with less sophisticated infrastructure and technology, supertalls are used to create an autonomous urban place with complementary uses for business people—offices, hotel, apartments, and shopping. This is a fully acclimatized environment with reliable electricity and other services—even if the local grid is not reliable. These buildings are advanced machines of efficiency that serve a lot of people in a small space.

Urbanization in China is so explosive that many cities have populations as large or larger than New York City's 8 million. Chinese cities offer a huge, growing demand for new buildings. Yet in the Middle East—for example, Dubai—developers try to create demand by designing tall buildings that will attract affluent buyers and investors in real estate. The idea is that glamorous buildings can create demand.

Is the role of the private developer the same as in the United States?

Governments often play an important role in Asia and the Middle East, either selecting developers or investing and building themselves. For example, with the Shanghai Tower [page 156], Gensler is working with a state-run construction and investment company. I think the tower will make money, but it's hard to compare Shanghai Tower to one developed by a purely private market.

How have American architectural firms gotten into the supertall inner circle of skyscraper designers? Obviously we can claim having been there first with our skyscrapers built in the late 19th century in New York and Chicago. But on our home turf we haven't been doing towers at this scale.

American architects and engineers had an edge when the global embrace of skyscraper design began about 20 years ago. Experience clearly matters in doing a supertall. Designers lead a team, and its members know each other and often work together in problem solving to build a better skyscraper machine. Understanding the challenges of designing a curtain wall, elevators, floor plans, and rentable floor area takes experience.

So how would Gensler get the commission to design the supertall Shanghai Tower since it had never designed anything higher than 54 stories (the L.A. LIVE, 2010)? Gensler might be the second-largest architecture firm in the U.S. in terms of revenue [Record, July 2011, page 24] and it has over 3,000 employees, but, as we know, a small coterie of American architects—along with Foster + Partners and others—gets these jobs. So far Gensler hasn't been part of the cloud club. Also whether the firm likes it or not, Gensler is better known for its commercial interior design work than for tall buildings.

As I understand it, Gensler builds relationships and trust, starting with interior design work for corporate clients, and then it pushes the boundaries from the office to the whole building. It builds trust with clients by coming in at the ground floor, so to speak. Gensler also has hired people and has assembled a team who had worked on supertalls elsewhere, such as SOM. Also it worked with Thornton Tomasetti and Cosentini Associates for the engineering of Shanghai Tower. I heard Arthur Gensler represented the firm for official meetings and ceremonies—which makes a strong impression with the clients.

Does it make sense to keep going higher, as we see with the Kingdom Tower? The architects involved in supertalls talk about sustainability values of such density and agglomerating various forms of transit within the project.

A lot of conditions are cultural. I was just in Frankfurt, a city that likes skyscrapers, but where retrofitting and recladding towers built in the 1960s to 1980s for energy-efficiency is an important trend. In terms of the supertall sustainable skyscraper, the next step is toward net-zero energy—that is, towers producing as much energy as they consume. This idea is already starting to happen with shorter towers.

Isn't there a point when a supertall is just too tall? Even if it is energy-efficient?

A lot of people believe supertalls are irrational acts. I think they are fundamentally rational, but also aspirational. To build a supertall you are taking a risk, more than if you were building a conventional structure, but you are trying to do something that gets extra attention. These bigger-than-life skyscrapers are beautiful. Supertalls are the celebrities of the skyscraper world.