In late September, the Council on Tall Buildings and Urban Habitat, a non-profit organisation that keeps the world’s largest database on skyscrapers, held its annual conference in Shanghai – two years after its last meeting there. “We’ve never done that before, gone back to the same city,” says Antony Wood, the council’s executive director. “But right now, most of the major advances in the typology, in design or in technical terms, are happening in China.”

As the global population rises and cities become more crowded, the fabric of urban centres is changing. Nowhere is the phenomenon more pronounced than in China, where a state-orchestrated urbanisation drive has prompted a megacity building bonanza characterised by skyscrapers and sprawl. By the end of 2015, one in three of the world’s buildings over 150-metres will be in China. Construction of the world’s second-tallest building, the 632-metre tall Shanghai Tower, is due to be completed next year.

Few people outside China have heard of Suzhou, a city in the eastern province of Jiangsu with a population of 1.3 million (China now has over 140 cities of more than one million people; America has nine). Yet if all goes to plan, Suzhou will soon boast the world’s third-tallest building, the 700m Zhongnan Centre. Other Chinese cities joining the upward rush include Shenzhen, Wuhan, Tianjin and Shenyang. By 2020, China is set to be home to six of the world’s 10 tallest buildings, although none will top the globe’s current highest, the 828m Burj Khalifa in Dubai.

Zoning laws, listed buildings and other well-intentioned hallmarks of democratic society can impede the march of progress; the opposition to London’s Shard would be unimaginable in contemporary China. The dramatic experiments in skyscraper construction and urban planning in the one-party state will, increasingly, hold lessons for cities the world over.

As a response to the dilemma of how to build densely while retaining liveability, the Shanghai Tower may be the closest architects have yet come to creating a “vertical city”. Designed by the American firm Gensler (pdf), the building forms a spiralling trunk that takes the amenities of the horizontal city block – homes, shops, offices, galleries, multiplexes – and stacks them on a vertical plane. Its “sky gardens” – around one-third of the site is green space – will showcase flora from around China, countering the predilection of developers to commercialise every square inch. According to Wood, “The commitment to public space … that’s what elevates the Shanghai Tower to be a potentially fantastic building.”

But this, he adds, is only the start; architects need to be more radical still. “I hear a lot of developers talking about putting so many uses in the building you’ll never have to leave it,” Wood says. “It’s terrible, is it not? Who would ever not want to leave the building?”

Instead, he calls for “sustainable vertical urbanism”, or the linkage of clustered tall buildings with sky bridges and elevated plazas replicating the ground floor in the air. A building should be responsive to topology as in vernacular architecture – Calgary and Khartoum should look different – and be designed in consideration of the buildings around it.

“It’s no accident that every science-fiction film, from Metropolis to Blade Runner through to Star Wars, envisages the dense, multi-level city of the future,” Wood adds. “The reason is because it completely makes sense.”

A proposed development that comes closer than most to this ideal is Cloud Citizen, which co-won a design competition in Shenzhen, a city in southern China. If built, the 1.7 million square-metre complex would be “as much a strategy for how to build future cities capable of giving back more to the environment than they cost, as it is a singular iconographic mega building complex with an identifiable and striking skyline,” say the architects. Sky bridges and plazas connect the towers, the tallest of which is 680m, in a cloud-like mass. Cloud Citizen would have offices, parks, cultural facilities and homes with an ability to harvest rainwater, produce food and create power from the sun, wind and algae – a mini-city within a city.

Super tall towers are as much about prestige as commercial gain. In China they are also symptomatic of a central government policy that has led to the frantic densification of cities. Premier Li Keqiang has called urabanisation a “huge engine” for growth as the government attempts to restructure its economy away from a reliance on exports and investment to one based on domestic spending. While most people in China were farmers 30 years ago, 50% of people lived in cities by 2011 and by 2030 it’s estimated one billion people, or 70% of the population, will be urbanites. Getting cities wrong could create slums, exacerbate climate change and encourage social instability.

The United Nations Population Division projects that by 2050, 66% of the world’s population will be urban, up from 54% today. Once population growth is factored in, this amounts to 2.5 billion more people living in cities. At the CTBUH conference in Shanghai, architects agreed that sprawl is not a sustainable solution to density. But building towers of dizzying height in a never-ending game of architectural one-upmanship is impractical too.

“We have to find the solution of how to move towards more density but to keep the human scale”, says Yosuke Hayano, principal partner of MAD Architects, a Beijing-based practice. “People are very sensitive to space.” MAD designs on a theory they call shan shui (“mountain water”), in reference to the way cities were strategically positioned in ancient China near rivers and mountains. The Zendai Himalayas Centre, a 560,000 sq m development in the eastern city of Nanjing due for completion in 2017, is a ring of undulating hill-shaped “towers” around a cluster of low buildings, with vertical louvres creating the impression of waterfalls. This mimicry of nature, MAD believes, imbues urban environments with humanity.

Ole Scheeren, a German architect based in China and Hong Kong, thinks architects need to “move away from the isolation that is embedded in the typology of the tower”. Scheeren co-designed the CCTV Headquarters in Beijing, which houses the state-run broadcaster and is one of the capital’s icons. It’s a striking cuboid loop of tower of 473,000 sq m. Alarmed at the “accumulation of singularities”, or mono-functional towers accruing in Asian cities, Scheeren’s buildings are prototypes for urban centres that need to be dense yet diverse, porous and livable.

For Interlace, a residential compound of 1,000 apartments in Singapore, Scheeren was tasked with building 12 towers of 24 storeys organised on a grid. “The sense of living in a community is not explored well spatially in a configuration like this,” Scheeren says. He toppled the towers, forming an interconnected mesh of buildings that resemble an orderly stack of Jenga blocks, creating space for parks, public courtyards and a running track.

“Where towers used to be relatively monotonous and simple repetitive structures they’re becoming more integrated and connected and also vertically diverse,” Scheeren says. “In that sense they will, I believe, attain more aspects of the words everybody likes to use: ‘vertical cities’.”