The arid expanses of the Sahara desert could be transformed within a decade, according to French architecture company OXO.

 

The Parisian firm has proposed building a futuristic mixed-use tower in the world's biggest desert. The tower's design is based on renewable resources like rainwater collection, solar power and geothermal energy to make it an entire sustainable city in one building.

 

French-Moroccan architect Manal Rachdi is behind the 450 meter tower design, which would have a floor area of 780,000 square meters (approximately 840000 square feet).

 

The design is conceptual and has not yet been commissioned. Rachdi said his motive was to think about new ways of urbanizing 'hostile' environments such as the Sahara.

 

More than 20 percent of the floor space is designed for offices, while a hotel and 600 housing units would be created on another 50 percent of the available floor space. The aim of the tower is to house a whole city, its designer explained.

 

The harsh desert environment is kept at bay in the design, with a central inner tower covered in plants to serve as a vertical garden.

 

OXO's desert tower incorporates shades and natural ventilation to help control the temperature. The geothermal technology proposed sees the rainwater collected being injected underground where heat from the earth would turn it into steam to generate energy.

 

Rachdi said the tower's use of sustainable technologies would make the vertical city very efficient, including using some of the rainwater collected for the irrigation of the vertical garden, despite the parched proposed location.

 

The Sahara desert is expanding southward at a rate of 48 km (30 miles) a year, forcing whole communities to migrate and pushing them on to land occupied by other groups, researchers said in a 2011 study.

 

Summer temperatures in the desert can top 45 degrees Celsius (116 Fahrenheit) and it is currently one of the most sparsely populated regions of the world, with around 4 million people living there, many nomadic.

 

The French architects envisage work starting on the project in 2025, with construction phased over 50 years.