The digital photos, shared videos, tweets and Facebook chatter that make up our online lives may appear to have no physical form, but they contribute to some very real environmental damage, the campaign group Greenpeace warns.
The vast amount of digital data that we upload and access via social networks and on websites such as YouTube is stored in what the internet industry calls the "cloud", by which it means a vast numbers of computers owned by the likes of Google, Yahoo and Apple.
These computers are housed in "data warehouses" across the world, and a Greenpeace report yesterday said that many of these power-guzzling sites had been built in parts of the US where electricity is generated mainly at coal-fired power stations. Coal, the most widely used source of energy in the US, is also the dirtiest, in terms of greenhouse gas emissions, the group says.
"The last thing we need is for more cloud infrastructure to be built in places where it increases demand for dirty coal-fired power," the report says. Greenpeace is putting pressure on internet firms to be more careful about where they build and says they should lobby more in Washington for clean energy.
A Facebook facility being built in Oregon will rely on a utility whose main fuel is coal, while Apple is building a data warehouse in a North Carolina region that relies mostly on coal, according to the report, Make IT Green. The companies criticised by Greenpeace say that they always take the environment into account, and Facebook said that it chose Oregon so that it could use natural means to cool its servers, instead of having to power air-conditioning.
"As the cloud grows, the IT industry's appetite for energy will only increase, so the industry must become strong advocates for renewable energy solutions and strong laws that cut global warming pollution," said Casey Harrell, a Greenpeace campaigner.
The organisation says that, at current rates of growth, data centres and telecoms infrastructure will consume about 1,963 billion kilowatts hours of electricity in 2020, more than triple their current consumption and more than France, Germany, Canada and Brazil combined.