A new survey is calling us out for what it calls our "dirty data" habits - the storing of millions of unnecessary photos and videos on servers around the world, creating a carbon footprint which researchers say is as big as that of the airline industry.The Institution of Engineering and Technology (IET), which commissioned the research, estimates that the average UK adult takes almost 900 photos a year, with an average of five photos taken for every one posted online. The duplicated and unwanted images left in storage accumulate 10.6kg of CO2 emissions per person annually, based on the energy used and carbon footprint generated by data storage, either personally or on shared servers. What it terms "dirty data" also includes unnecessary data streaming and downloading, and storage of emails and messages. The total CO2 generated in the UK alone from unneeded stored data, according to the report, is the equivalent of 112,500 return flights from London to Australia. Individually, the carbon footprint our unused data generates over a lifetime is equivalent to driving from Land's End to John O'Groats.