The countless outdated e-mails and other files that inhabit your inbox, and the forgotten photos and videos you shared long ago on Facebook, are all readily available just a few clicks away. We never give much thought to their existence, and rarely do we refer back to them because, well, they belong to the past, so they should stay there forever. Yet we don't dare delete them either, just in case.

All that information is stored silently but permanently somewhere on a server, in an air-conditioned warehouse guzzling electricity.

Many people may not realize this, but the physical reality of our digitalized world is not as sleek as the information-technology industry would like us to see. On the contrary, it is huge, ugly, noisy and environmentally hostile.

And our data-driven lifestyles and the insatiable need for faster, more comprehensive and instantaneously delivered information are no longer even Earthbound. For instance, our Global Positioning System (GPS) tracking system, fully functional since 1995, constantly receives signals from satellites that guide each turn we take. To get our exact geographic location in real time, this transmitted data needs a fast calculating and storage facility -- a server.

At the heart of every major IT company are sprawling and monstrous data centers, each with hundreds of thousands of servers, often nestled in farm fields and river valleys. What attracts companies to these locations are not pastoral landscapes, but cheap and plentiful electric power. These data centers feed on enormous amounts of electricity, with each square meter of floor space gulping up as much power as an entire average U.S. household.

It is not just the racks of servers that consume electricity. In fact, servers themselves account for less than a third of the total data-center energy consumption. The cooling systems -- those massive air-conditioning machines that keep hard drives, servers and other network gears from overheating -- are particularly energy-intensive.

The Environmental Protection Agency recently estimated that data centers consume about 2 percent of the total electricity in the United States a year. That's about one gigaton (one billion metric tons) of carbon-dioxide emissions, a significant rise from less than five years ago, when consumption was at 1.5 percent.

What's worse, a McKinsey study finds that the average server use is less than 15 percent of its peak, with about 60 percent of servers sitting idle at any given time -- all while continuing to draw huge amounts of electricity in anticipation of an unexpected surge in use. This mentality of underutilization is the norm in the risk-averse IT industry. In comparison, even cellphones and other portable devices consume less when in standby mode -- less than a tenth of their peak power use. The IT industry could and should do much better than the status quo.

The industry metric for energy-efficiency -- "power usage effectiveness" or PUE -- is the ratio of the total power consumption to the power used by servers only. For example, a PUE close to one means high energy-efficiency because little is wasted on cooling or lost in the electrical distribution system. The larger a PUE, the more energy-inefficient the data center is. Generally, most data centers had a PUE of 2.0 or more, says a 2007 Environmental Protection Agency study. Google asserted that its average PUE was 1.21 in 2009, and Microsoft reported a 1.22 PUE in the same year.

But it is not enough for only a few major players in the industry to achieve high energy efficiency. Everyone should get involved, because our environment is at stake. Sustainability and social responsibility are not just trendy political and marketing talking points; they should translate into more concrete and concerted actions.

The bottom line is that everyone is culpable and everyone owns responsibility for the egregious energy consumption in data centers. So, next time, please think twice before making unnecessary purchases online, uploading photos and "free" big file attachments.

Cutting back on the many unnecessary online activities not only saves time and money, it helps our environment. Making the leap now is more of a change of mind-set and working habits than waiting for the perfect technology to come.

Isn't there a phrase: "Think globally and act locally"? Let's do it!


Ming Xu is a second-year doctoral candidate at the School of Engineering of Brown University. This article was written for the Providence Journal.