Google has come clean with its environmental impact - stating that it has around the same carbon footprint as the United Nations at 1.5m tonnes of carbon emissions per year.

However, good old Uncle Goog is keen to stress that its output from its data centres is around half of the industry average, and states that Gmail, for example, is 80 per cent more efficient than a desktop based email solution due to its more efficient servers.

Google's data centres use about 1 per of Koomey's worldwide data centre estimate, meaning that it's responsible for about 0.01 per of global electricity use.

"Our commitment to reducing environmental impact extends to our offices worldwide," states the search giant. "Most of our on-campus green initiatives were started by Googlers, and have now grown into company-wide efforts. From the solar panels on our roofs to our bike-to-work program, these initiatives eliminate the equivalent of more than 10,000 metric tons of CO2 per year."

If you're concerned about the impact your own Google based activities are having then consider these scenarios set out by the company:

Using Google products for a month, its servers use less energy per user than leaving a 60W light on for 3 hours.

100 searches is the equivalent of leaving your laptop on for an hour or having a 60W light-bulb on for 28 minutes.

3 days of YouTube uses the same energy as manufacturing, packaging and delivering a DVD.

1 year's worth of Gmail is "less than the energy it takes to drink a bottle of wine, stuff a message in the bottle and toss it in the ocean".

"Specifically, streaming 1 minute of YouTube requires 0.0002 kWh, and generates approximately 0.1 g carbon dioxide," a Google statement read. "Google uses 2.2 kWh per Gmail user every year, and generates 1.2 kg of carbon dioxide."

So next time your checking your mail, or doing an unnecessary search, think. You could be downing a bottle of Pino Grigio and polluting the sea instead.