Nine of the world's tallest 20 buildings being built are in China and, while these are symbolic of China's success, ways to make these structures more sustainable are also being considered, writes CLIFFORD COONAN

WHEN IT COMES to skyscrapers, the sky, it seems, is no longer the limit. Asia is currently swept with a fever for “megatall” buildings, constructions more than 600m high and powerful symbols of national pride and prosperity, and an ability to innovate.

Developing countries love them, far outstripping growth in the US and Europe, with a wave of “megatall” building construction fuelled by faster economic growth and a wish to show off their wealth.

The world’s second-tallest skyscraper today is the 508m Taipei 101 in Taiwan. Chicago’s 442m Willis Tower, the eighth tallest, is the only building outside of Asia or the Middle East in the top 10.

The world’s first kilometre-high building, the Kingdom Tower in Jeddah, is due to be completed in 2018, overtaking the 818m Burj Khalifa in Dubai. And we can expect the world’s first mile-high (1.6km) building within the next decade or so.

Timothy Johnson, chairman of the Chicago-based Council on Tall Buildings and Urban Habitat (CTBUH) group, said Chinese tall buildings were a mixture of functionality and real estate costs, like anywhere else.

“But also the image. It’s all about telling the story of the accomplishments of China,” said Johnson, who is a design partner at the firm NBBJ. He was speaking at the CTBUH’s first congress in China, where nine of the world’s tallest 20 buildings under construction are going up.

“If you look back at the Sears Tower or the Hancock Centre in Chicago, they are about image. I don’t think tall buildings are going to slow down. The economy has been going up and down in the world forever. Human accomplishment and urbanisation will continue to drive this for the future,” said Johnson, who designed the Sail at Marina Bay in Singapore, the world’s 10th tallest residential building. He believes the first mile-high building will be here by 2025.

China’s stats on tall buildings can give you vertigo. There are 239 buildings taller than 200m in advanced stages of development in China, far more than in any other country. At the end of last year, there were only 61 buildings taller than 300m in the world, but in five years China alone will have more than 60.

In 1970, 92 of the world’s 100 tallest buildings were located in north America. By the end of 2012 only 29 of the top 100 will be in north America.

Fittingly, the CTBUH congress took place in the Jin Mao Tower, an 88-storey skyscraper in the Pudong district of Shanghai. Until 2007 it was the tallest building in China, the fifth tallest in the world by roof height and the seventh tallest by pinnacle height.

Next door is the Shanghai Tower, currently under construction which, when completed in two years’ time, will stand 632m high with 121 storeys.

It’s a breathtaking achievement, although it looks like another Chinese skyscraper, the Wuhan Greenland Financial Centre, will outstrip even this height by four metres.

The 660m Ping An Finance Centre, a 115-storey high skyscraper being built in Shenzhen, will be the second-tallest building in the world when it is completed in three years.

“We are advancing. When tall buildings were first designed, it was about making them stand up. Now it’s about making them sustainable,” said Johnson.

“The next generation will be buildings that produce their own energy, so they are not a draw on the grid, they actually add to the grid. And maybe the next step is buildings that you can grow things on,” said Johnson.

The idea of the skyscraper as a reflection of a country’s ability to innovate is particularly strong in China, which completed 23 buildings over 200m last year, more than any other country.

Five of those were in Shanghai, and the city’s vice-mayor, Shen Jun, believes tall buildings are an inevitable part of the urban make-up of Shanghai, China’s most populous city.

“Land resources are not renewable,” he said. “We have no choice but to build high-rises to save land.”

Antony Wood, executive director of the CTBUH and an associate professor at the Illinois Institute of Technology, believes there is a long way to go to make tall buildings truly successful.

“Speaking as a professor of architecture, I think tall buildings are predominantly disappointing. Tall buildings are part of the answer to the cities of the future, but they are only several baby steps along the path to sustainability,” he said.

“The focus is on supertall, but there are only 67 supertall buildings in existence. Yes, tall buildings are getting taller and there are more of them. We have got to bring the horizontal into the vertical city. There are 20 or 30 examples of buildings that create the urban habitat in the sky. That’s where it needs to go,” he said.

Adrian Smith is the Chicago-based designer of the world’s current tallest building, the Burj Khalifa, and he is working on the building that will assume that mantle when completed, the Kingdom Tower.

“In the near future, it depends how the economy goes in China but from an urbanistic point of view, there are 179,000 people moving into urban areas every week. Do they go into a horizontal or a vertical city? It’s a question of economics,” said Smith.

There are multiple reasons to build tall. The Kingdom Tower will be about 50 floors higher than Burj Khalifa, although Saudi billionaire Prince Alwaleed bin Talal’s investment company, which is building the tower, is seeking a loan to help pay for its construction.

Smith’s company is doing a lot of research into density.

“Density is still very important in creating an urban environment that people want to live and work in,” said Smith. “That density in China is happening because the cities have the work. In the country they find agriculture and that’s it.

“If we want to continue making supertall buildings and we want them to be sustainable, they will need to be able to produce power. You can design them to reduce energy usage, but that’s not enough. You have to put power-generating technology into these towers to drive down the carbon emission,” said Smith.

The only thing stopping buildings going higher is money, said Richard Tomasetti, founder of structural engineering firm Thornton Tomasetti.

“There is no problem going to a mile high. Structural engineers are off the hook – we’re not limiting anything,” he said.

Li Guoqiang, professor of structural engineering at Tongji University, saw the start of the boom in Shenzhen, the financial centre just across the border from Hong Kong, during the 1980s.

“I participated in the first tall building over 100m in Shenzhen. At that time China had no experience in the design and construction of tall buildings. We imported the steel from Japan and the fabrication was done in Japan. The workers were trained in Japan at that time. Right now, China has much improved. Next, China needs to develop techniques, such as techniques in structural terms to deal with earthquakes, which is very important in China,” said Li.

“Now we have to use less money to produce the building, less energy and fewer materials. On energy, we can look at solar or wind energy. There is a huge vibration in a building, so possibly in the future we can use this vibration to make energy.

“When I first moved to Shanghai the 1980s, there were 10 million people here. Now there are 20 million people. There are more and more people from the countryside moving to Shanghai. We need tall buildings for these people. The land in Shanghai is limited,” he said.

Ole Scheeren, who quit Rem Koolhaas’s OMA to form his own office two years ago, believes the attacks on the World Trade Centre in New York in 2001 changed the view of the tall building.

“9/11 was a crisis of the skyscraper as an icon of power. It made us rethink as architects what we do. Critics decided architecture had to change and declared the death of the icon,” said Scheeren.

“If we think about today, we are at the point where possibilities explode or implode. Sustainability is not just about ecology, it’s also about our social ability to live together. That remains one of the greatest challenges.”