New technology means lifts can go as high as a kilometre in the sky.

Experts say that will revolutionise the height of current skyscrapers, meaning that tall buildings only dreamed of before become not only reality, but common place. Joel Flynn takes a look.

It rendered stairs obsolete, but now the lift, or elevator, is reaching new heights. Literally.

And it could change city skylines all over the world.

New technology called Ultrarope, invented by Kone Lifts, means elevators can now reach up to a kilometre in the sky.

That's double their previous ceiling, and means new buildings can get taller. Architecture critic Tom Dyckhoff.

SOUNDBITE: Architecture Critic and Broadcaster, Tom Dyckhoff, saying (English):

"I really think this is going to revolutionise how we talk about them and how we talk about tall buildings. They're going to become much more common, at a height we have never experienced before."

Ultrarope is a new material used to support the weight of lifts.

Finnish manufacturer Kone says it can pull lifts up at a rate of four floors per second. And it's not just the maximum height of buildings it could change.

Johannes De Jong from Kone says it could also revolutionise energy costs.

SOUNDBITE: Kone Major Projects Head of Technology, Johannes De Jong, saying (English):

"Moving masses can be reduced by roughly 45 percent if you are looking at a high-rise building of about 400 metres, by 60 percent if you look at high-rise buildings of about 500 metres. That has a tremendous impact on the energy consumption."

Around 20 new buildings over 600 metres high are currently being planned across the world. That's twice the height of the Shard in London - currently Europe's tallest building.

Anthony Wood is from the Council for Tall Buildings and Urban Habitat.

SOUNDBITE: Council for Tall Buildings and Urban Habitat (CTBUH) Architect and Executive Director, Antony Wood, saying (English):

"It's going to enable more efficient, higher buildings in the places that warrant those buildings, but it's going to result in better energy efficiency in all tall buildings around the world."

Not everyone's a fan of high-rise living, but the UN estimates by 2050 seven out of every 10 people will be living in cities compared to around half of people now .

Building upwards is increasingly being seen as the most sustainable urban solution.