Believe it or not, when you upload a video to YouTube you may be doing more harm to the Earth's climate than when you fly in an airplane.

Every minute, 400 hours of video are uploaded to YouTube. This, like everything else on the internet, requires big servers to process the data. These data centers are located around the world, sometimes in small rooms and sometimes in huge "data farms" the size of 15 football fields. Together they use up around 420 terawatt hours of electricity a year, about 3 percent of the world's electricity supply.

These data centers gobble up more electricity in a year than all of the UK, and now account for about two percent of global greenhouse gas emissions - putting it on par with aviation. And while aviation emissions are expected to increase by 50 percent by 2050, data center emissions could increase by as much as 300 percent by 2026, according to researchers from the University of Leeds in England.

Why does this server activity use so much energy?

A Google data center in Pryor, Oklahoma

"They run 24/7," Pierre Delforge, director for the high-tech sector at the Natural Resources Defense Council in the United States, told DW. "For every unit of energy spent to power a server, nearly another unit is spent on the building infrastructure that houses them, mostly to keep them from overheating."

And it's not just the processing; data storage also uses a large amount of energy.

Google's gambit

The good news is that there are ways to combat this rise. This week, tech giant Google announced that it will power 100 percent of its global data centers with renewable energy starting next year. This will be an increase from currently 44 percent.

"Our engineers have spent years perfecting our data centers, making them 50 percent more energy efficient than the industry average," said Urs Hölzle, Google's senior vice president for technical infrastructure. "But we still need a lot of energy to power the products and services that our users depend on. We began purchasing renewable energy to reduce our carbon footprint and address climate change - but it also makes sense business-wise."

Buying the electricity for the centers, and providing the cooling and exhaust systems to stop them from overheating, is enormously expensive. But renewables costs are going down, with solar costs decreasing by 80 percent over the past six years. This power can often be bought using long-term contracts that set a fixed price for 10 or 20 years.

"Electricity costs are one of the largest components of the operating expenses at our data centers, and having a long-term stable cost of renewable power provides protection against price swings in energy," said Hölzle.

Google has promised to source all its data center electricity from renewable sources

According to data from Bloomberg New Energy Finance, Google purchases by far the most renewable energy of any of the tech giants, with commitments reaching 2.6 gigawatts of wind and solar energy.

Greenpeace's annual "click clean" report, which ranks tech companies on their environmental performance, ranks Google in top place. Amazon and Facebook follow in the middle range. Oracle is one of the worst-ranked tech companies in the report.

More efficient data

But of course, Google's renewable energy would otherwise be used for a different electricity need. Google's initiative doesn't address the root of the problem: the massive increase in internet activity. There are only two ways to solve this problem: force people to cut down on internet use, or change the way data is processed.

Delforge says there are ways to save energy so that internet usage doesn't necessarily have to be cut back in order to stop data center emissions from growing.

A report released in June by the US Department of Energy's Lawrence Berkeley National Laboratory found that currently available best practices, combined with a shift from local data centers to more efficient cloud computing centers, could cut data center energy usage by 45 percent by 2020 in the United States. This would save 50 million metric tonnes of carbon annually.

The report also found that as much as 30 percent of a typical small-office-based organization's electricity bill may be due to powering and cooling servers running around the clock, even when they are not doing any work. Energy efficiency practices could cut this usage and save companies up to $3 billion annually.

"While the large computing operations like those run by Google and Facebook have drawn the most attention, they still make up a relatively small fraction of data center energy use," says Delforge. "The vast majority is still consumed in small, medium, and large corporate data centers as well as in the multi-tenant data centers."

In fact, smaller server rooms and closets are responsible for nearly half of US server electricity consumption.

Facebook has opened this data center in Lulea, Sweden, close to the Arctic Circle

Another solution to reduce energy use is to move the servers to colder climates, where less effort is needed to cool down the servers. Facebook has recently opened a 84-acre data center in the north of Sweden, 70 miles from the Arctic Circle. But even in this environment, 500 large fans will be required to cool the machines.

Last year Apple committed to invest 1.7 billion euros to build new cloud-based data centers in Denmark and Ireland. These new centers, processing data from iPhones and measuring 160,000 square meters each, will be powered exclusively from renewable energy.

Meanwhile, carbon reductions can also be found by using the heat generated by the servers for district heating. Last month in November, energy company Fortum and Ericsson signed a collaboration agreement on utilizing the waste heat of Ericsson's data center, located in the town of Kirkkonummi in Southern Finland, for district heating.

Ericsson's data center currently generates 10,000 to 15,000 megawatt-hours of waste heat annually. Using that would mean the town's heat will not have to be generated elsewhere, saving carbon emissions.

"It might not be the first thing that comes to mind when we think about data centers - but keeping them cool actually means producing huge amounts of excess heat," says Paul Voss, managing director at district heating association Euroheat & Power.

"The choice between throwing that heat away into the atmosphere, or delivering it to nearby homes through district heating networks is an easy one."

Analysts say that there are many ways to alleviate the growing emissions of data centers. But companies and governments need to act fast, because the exploding growth of the internet is likely to result in an explosion of emissions as well - unless solutions are found.