GLOBAL CHALLENGES

300 Exabytes: An Inventory of the World's Information

Rebecca Kutzer-Rice | Date: 02-15-11 | Comments

In the first examination of its kind, a new study calculated the total amount of information stored and communicated by the entire human race. Beware: These are some pretty big numbers.

If you're like most people living in this digital age, a hefty quantity of information passes through your hands each day. You probably sort through a few dozen e-mails, type out a text or two, watch television, even browse your Twitter feed. But how much information does the entire human race deal with? According to researchers, a lot more than you might expect.

A new study from a team at the University of California and published in Science magazine examines the total technological capacity of the world�how much information people have the ability to store and communicate. That amount? At least 295 exabytes. That is, nearly 300 billion gigabytes, or the equivalent of 1.2 billion average-sized hard drives.

Dr. Martin Hilbert and his team calculated the total amount of information that is stored, communicated and computed by humankind. (Source: USC Annenberg School for Communication & Journalism)

"Put another way," explains a statement from the researchers, "if a single star is a bit of information, that's a galaxy of information for every person in the world. That's 315 times the number of grains of sand in the world. But it's still less than one percent of the information that is stored in all the DNA molecules of a human being."

"If we were to take all that information and store it in books, we could cover the entire area of the U.S. or China in three layers of books," Dr. Martin Hilbert told the BBC's Science in Action. Hilbert is a doctoral student at the USC Annenberg School for Communication & Journalism and was the lead author of the study.

The impressive calculation includes information from 60 different types of media�from books and newspapers to CDs and USB drives.

"We live in a world where economies, political freedom and cultural growth increasingly depend on our technological capabilities," said Hilbert in a statement. "This is the first time-series study to quantify humankind's ability to handle information."

The research also examined the history of information growth. It defines 2002 as the beginning of the digital age, since this was the year when digital storage capacity overtook analog storage capacity. By 2007, the researchers say, almost 94 percent of the world's information was in digital form.

In 2007, humankind sent over 1.9 zettabytes of information through broadcast technologies�such as television and radio�alone. According to the study, that's the information equivalent of every person reading 174 newspapers per day.

The study examined the 20-year period between 1987 and 2007. During this time, worldwide computing capacity grew by 58 percent each year�10 times faster than the growth rate of the U.S. gross domestic product (GDP).

"These numbers are impressive, but still miniscule compared to the order of magnitude at which nature handles information," Hilbert commented. "Compared to nature, we are but humble apprentices. However, while the natural world is mind-boggling in its size, it remains fairly constant. In contrast, the world's technological information processing capacities are growing at exponential rates."

The research was published online by Science magazine in February. A short video featuring Hilbert discussing his findings can be found here.