Science: Researchers Take Inventory of the World’s Information Capacity

A new study reports an inventory of the world’s technological capacity to store, communicate and compute information over the last two decades.

First, a refresher: A bit is the smallest unit of information, and a megabyte equals 8 million bits.

Now, the results: In 2007, humankind was able to store 295 trillion optimally compressed megabytes, to communicate almost 2 quadrillion megabytes, and to carry out 6.4 trillion MIPS (million instructions per second) on general-purpose computers.

To put one of those numbers in perspective, if those 295 exabytes of stored information were saved on CD-ROMs, the stack of CDs would reach from the Earth to beyond the moon, according to the study’s authors, Martin Hilbert of the University of Southern California and the United Nations ECLAC in Santiago, Chile, and Priscila López of the Open University of Catalonia in Santiago.

Though seemingly enormous, this amount is still smaller than the number of bits stored in all the DNA molecules of a single human adult.

The researchers surveyed 60 categories of analog and digital technologies during the period from 1986 to 2007, and the results reflect our near complete transition to the digital age.

“These technologies are very important in our daily life, for economic development and political freedoms,… so it’s simply important to quantify them. Because in a scientific sense, to measure is to know,” Hilbert told Science Podcast host Robert Frederick.

The fastest growing information operation has been computation, Hilbert and López report. The world’s capacity for bidirectional telecommunication (such as Internet and phone networks) grew at 28% per year, while capacity for unidirectional information diffusion through broadcasting channels (such as TV and radio) grew at the much more modest rate of 6% per year.

Humankind’s technological memory has almost completely been digitized in what historically is no more than an instant: While still 75% of our stored information was in analog format (mainly in video cassettes) in 2000, 94% of it was in digital format by 2007.

Hilbert and López estimate that the world’s technological capacity to compute information via application-specific devices (such as electronics’ microcontrollers or graphic processors) has roughly doubled every 14 months over the past two decades, while the capacity of the world’s general-purpose computers (such as PCs and mobile phones) has doubled every 18 months.

The global telecommunication capacity per capita doubled every two years and 10 months, while the world’s storage capacity per capita required roughly three years and four months to increase twofold.

The researchers note that these growth rates are much faster than the single-digit rates of change—for example, GDP, population growth, or educational levels—that social scientists are normally accustomed to.

The paper was published online at the Science Express Web site.


Read the abstract for “The World’s Technological Capacity to Store, Communicate and Compute Information,” by Martin Hilbert et al.

Listen to a Science Podcast interview with Martin Hilbert.