How High Can We Possibly Build?

How High Can We Possibly Build?

We humans clearly love building tall structures. For thousands of years we’ve been trying to one-up each other with taller and taller monuments, monoliths, towers and skyscrapers.

There are various examples of record-breaking builds in our ancient history. From the Tower of Jericho, built sometime around 8,000 BCE and rising just 28 feet from the ground, to the Great Pyramid of Giza, which was finished in 2,560 BCE and – at a then-massive 481 feet – remained the tallest structure on Earth for nearly 4,000 years.

England’s Lincoln Cathedral held the height record for more than 200 years, when it was constructed in 1311. And it began a Middle Ages trend for churches, abbeys and cathedrals to continually outdo each other until the late-1800s - when various notable structures, including the Washington Monument and the Eiffel Tower, held the crown at one stage. Then it passed onto a series of North American architectural achievements during the 20th century, with the Chrysler Building, the Empire State Building, and the CN Tower all breaking records. But the CN Tower’s thirty-two-year time at the top finally came to an end in 2007 when the Burj Khalifa in Dubai became the tallest freestanding structure in the world at nearly 830 meters, or 2,722 feet.

Even the Burj Khalifa looks set to be beaten though, as construction is currently underway on the Jeddah Tower, an unprecedented structure located in Jeddah, Saudi Arabia. It’s in line to become the world’s first one-kilometre-high structure, soaring into the clouds at a staggering 3,280 feet – more than 500 feet taller than anything else there has ever been.

But is the Jeddah Tower the absolute highest we can build? Incredibly, it’s not even close. Theoretically speaking, we can go much, much higher… But at the cost of land, physical comfort and vast sums of money. It all depends on how far and wide we can keep expanding the area of a given structure’s base.

That said, the higher we do go, the more problems arise. For one thing, physically constructing tall buildings is difficult and specialist work, and materials cost a lot of money. Many investors simply aren’t willing to stump up the exorbitant amount of cash necessary for the construction of a record-breaking tower. By the time it’s complete, the Jeddah Tower will’ve cost an estimated $1.2 billion – and that’s before you’ve even factored in the energy costs to run the place!

Building materials are also incredibly tricky to work with the higher up you go. Hauling concrete 3,000 feet in the air ispretty difficult even for expert engineers, so those in the trade point to carbon fibre as the future of construction, But, this option is (not surprisingly) insanely expensive.

Finally, and an often-forgotten factor, transporting people and things to the top of completed tall structures isn’t easy. Looking up at the awe-inspiring skyscrapers of the future would be cool, but actually going up probably wouldn’t be. In fact, we’d need to create a whole new way of moving from top to bottom. Standard elevators simply won’t work at higher heights, because the cables used become too heavy. Which means we’d either need multiple elevators and purpose built ‘elevator stops’, or an entirely new system altogether. But even then, we’d have to contend with all sorts of fun things that happen to the human body the higher we go – including nausea, dizziness and even altitude sickness. All of which are made worse should a tall building begin to ‘sway’ at the top.

However, ignoring all of these issues, there’s virtually no limit to how high we can feasibly build. Timothy Johnson, of the Council on Tall Buildings and Urban Habitat, reportedly once helped design a building in the Middle East set to be a mile and a half tall – although he did concede that it would require multiple new inventions to succeed. For Johnson, the possibility of the project would only come down to capital – and whether enough of it existed.

Another (and more high-profile) hypothetical building providing some proof for what might be achieved is the X-Seed 4000, designed by Peter Neville. While it’s never been built and likely never will be, it has been thoroughly and completely planned out – to show that it could in fact be created. Designed for a Japanese firm – the Taisei Corporation – the X-Seed 4000 would’ve required around three million tonnes of steel to essentially operate as its own self-sufficient environment, with individual neighbourhoods linked by the building’s own trainline. It would’ve needed a massive six-kilometre-wide base, but it would have reached up to four kilometres in height, or about 13,000 feet - so tall that the engineers would’ve had to devise a system to protect upper-floor occupants against the intense changes in air pressure. And it’s estimated cost? That would be $1.2 trillion.

But even that pales into insignificance alongside what William Baker – a structural engineer who helped design the Burj Khalifa – predicts we could achieve. Speaking to CityLab in 2012, Baker believes we can build as high as a mountain – or even higher – if we fashion a wide enough base. Quite how big that base would need to be is debateable, but around 4,000 square kilometres should do the job – or an area about the size of Cape Verde. That’s a freestanding structure as tall as, or even taller than Mount Everest – if you can believe it.

But Everest is nothing when compared to space! Yes, one day we could create a structure that reaches into space itself. It’s an at-this-point entirely theoretical idea called the space elevator, a proposed future transportation system aiming to shoot objects into orbit without the use of rockets. Feeling like something straight out of science fiction, it would consist of a massive cable bolted to the surface of the Earth and extending up and up and up, until it reaches geostationary orbit at 36,000 kilometres, and centrifugal force enables it to stand under tension. Unfortunately, this incredible construct would require as-of-yet undiscovered building materials… Although the 2014 creation of diamond nanothreads does provide at least one possible option.

So, not even the sky is the limit when it comes to how high we could possibly build. Humanity’s tallest structure rose just 8.5 metres from the ground, about 10,000 years ago. Today, we’re close to one thousand metres. In the future, our freestanding structures could ultimately dwarf the mightiest of mountains, or even extend out into space. The theoretical designs are already in place. Now we just have to wait… And pray that we’ll never need to ‘take the stairs’.