From the Empire State to the 1km-tall Jeddah Tower, our roundup of skyscrapers in numbers examines the race to be crowned world’s tallest building

In a world of ever-reducing space, a skyscraper is an efficient way to create homes and offices without too large a footprint. It is interesting, then, that so many skyscrapers are full of hot air. In the race for the biggest buildings, architects have fallen back on antennae and pointed spires – with the result that skyscrapers are not so much efficient uses of space, but overblown vanity projects.

Take the world’s tallest building, the Burj Khalifa in Dubai. It’s impressive at 828 metres tall, but nearly a third of that (29%) is unoccupiable, according to the Council on Tall Buildings and Urban Habitat. The Burj al Arab, also in Dubai, is much worse in this respect, with 39% of the entire building unusable. In fact, Dubai has five towers listed as the tallest buildings in “vanity height” – unusable height for the sake of it. Across these five, some 31% of total space is completely wasted.

So should they really be considered the tallest buildings anymore? The Burj Khalifa’s true height is only 584 metres, making it much closer to the height of the Makkah Royal Clock Tower in Saudi Arabia, which has a true height of 559 metres. The Empire State Building in New York, on the other hand, is still a remarkably impressive achievement next to these: although it only stands at 381 metres tall, it loses just 1% of its stature to unoccupiable space. The Shard in London is 20% unoccupiable.

The fight to have the tallest building was relatively tame until the last 20 years. Built in 1931, the Empire State Building spent over four decades as the tallest building in the world. In 1973, the title went to the World Trade Center Towers in New York, and then quickly to the Willis Tower in Chicago in 1974.

Change since has been rapid. Since the early 2000s, Asian countries – China in particular – have acquired the capacity, resources and vision to create competitively tall skyscrapers. The construction of the 452m-tall Petronas Towers in Kuala Lumpur in 1998 gave the crown to the Malaysian capital – until Taiwan eclipsed it in 2004 with Taipei 101. Meanwhile, the Gulf states entered the race with buildings such as the Burj Khalifa and the Makkah Royal Clock Tower, which looms over the largest mosque in the world.

Now, of the top 20 tallest buildings, four are in the Middle East, four in the US (including the new One World Trade Center), and the remaining 12 spread across Asia, including the twisting Shanghai Tower.

What next for skyscrapers? By 2020 there will be more than 16,000 of them globally, with many more on the way. In London alone, there are 377 ongoing skyscraper projects, with 76 currently under construction; No 1 Undershaft at 290 metres will almost rival the Shard. New York, which still has more skyscrapers than any other city (1,302!), has 329 ongoing projects. Toronto, which already has 480, is planning 281 more.

Interestingly, Hong Kong seems to have run out of enthusiasm – or space: it has just 50 more skyscrapers in the works to join the 806 it already hosts.

As for where the crown goes next, however, there is not that much competition. In China, the proposed H7 Shenzhen Tower will reach 739 metres, while the Signature Tower Jakarta is expected to hit 638 metres. Both come close to the Burj Khalifa, but not close enough.

In Dubai itself, plans are afoot to create what developers believe will be the tallest twinned skyscrapers in the world, as part of the Dubai Creek Harbour development. Another project, Santiago Calatrava’s Dubai Creek Tower, is under construction and aims to be “a notch taller” than the Burj.

By far the biggest and most ambitious skyscraper proposal, however, comes from Saudi Arabia: the Jeddah Tower. When completed in 2020, it will stretch a full 1km high.

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