If server farm temperatures were raised by just 5 degrees C, globally, 1.7 million metric tons of CO2 emissions could be avoided at present levels of usage (as well as enough energy saved to power Taiwan for a month). That is about the amount of CO2 sequestered by 43 million trees growing for a decade—or roughly a new Nordic forest covering Scandinavia, according to Intel.
Another step is to change the layout of the microprocessors—each one heating up as it computes—inside a server. They can be arranged so that they are not lined up, which results in each preheating the other, but rather are spaced to allow for cooling airflow.
The architecture of the server buildings themselves can help, too. Facebook's new server farm in Prineville, for example, cools itself completely with the surrounding air, which has itself been cooled through evaporation rather than an air-conditioning chiller employing ozone-destroying and greenhouse-exacerbating chlorofluorocarbons or a cooling tower. And data centers are also learning how to shrink and grow on demand—meaning more or less computers are on at any given time. "Most servers in the U.S. or the world are very underutilized," notes senior engineer Pierre Delforge of the Natural Resources Defense Council, who has been helping to reduce this large source of electricity consumption. Many servers are run at as little as 5 percent of capacity, or 15 to 20 percent at best, while running inefficient software code that, in some cases, was programmed 50 years ago.
It is not just power and money at stake. Data centers employ some 80 billion gallons of water for cooling annually, according to Intel. If the chipmaker can figure out how to operate at temperatures above 40 degrees C, "it gets rid of water," Rego says.
In the end, though, simply building such server farms in places that are naturally cool and renewably powered—think Facebook opening such a warehouse in Luleå, Sweden, with its chilly air and abundant hydropower in 2014—may prove a like-able move. "When you can use cold air or, even better, cold water, you don't have to make cold air or cold water through chillers and therefore save a significant amount of energy," Delforge explains. "Data centers generate a lot of heat." But with energy efficiency and proper siting, maybe all the hot air expressed on Web sites like Facebook can avoid exacerbating global warming.