The amount of information being stored on digital devices is growing at a faster rate every year, according to a new study.
The research, by Dr Martin Hilbert from the University of Southern California and Dr Priscila Lopez of the Open University of Catalonia, looked at the various ways humans use technology to store, communicate and compute information.
The study appears in the latest issue of the journal Science.
In 1986, the first year investigated by the researchers, information was overwhelmingly stored in analog format: mostly in video, but also on devices like vinyl LPs, audio cassette tapes, photographs, books and newspapers.
But by 2002 the balance had shifted and there was more space for data on digital memory devices - such as hard drives, DVDs and computer chips - than on the analog devices they measured.
Just five years later, in 2007, the researchers found 94 per cent of the world's information storage capacity was in digital form.
Amazing rate of growth
Hilbert says global storage capacity doubles about every three years and four months, and in 2007 reached 295 exabytes (295,000,000,000,000 megabytes).
"If I would store all this information in CD-ROMs, I could make a pile that goes from here to the Moon and one quarter of the distance beyond," he says.
"A library of a large research university... contains about 40,000 books. If you were to take the entire information that is stored in the world's technological devices and convert it into books, that is equal to around 15 times the books that are in these buildings, per person in the entire world."
He says storage capacity grows about four times faster than the world's economy and that telecommunications capacity is growing at roughly the same speed.
On average, each person in the world communicated the equivalent of six newspapers every day using two-way technologies like telephones, based on the calculations for 2007.
Even more information was sent through broadcast technology - data equivalent to every person in the world reading 174 newspapers every day.
Hilbert says the computational power of technology to process information is growing even faster than its storage or telecommunication capacity.
Natural world a long way ahead
But human technology still pales in comparison to the natural world.
"Computational power grows around nine times faster per year than our economic power," he says.
"These numbers are impressive and mind-boggling, but compared to the information-processing capacity of nature, they are actually very small.
"If all computers in the world run simultaneously, in one second they can make as many instructions as... a human brain can make nerve impulses in one second."
The researchers say the 295 exabytes of global storage capacity equates to less than 1 per cent of the information in all the DNA molecules of a human being.