Google has hit back at a report that claimed two searches on its site create the same amount of carbon dioxide as boiling a kettle.

The report, printed in The Sunday Times, suggested that one Google search generates 7g of carbon dioxide from its data centres.

But Google says the research, from physicist Alex Wissner-Gross of Harvard University, puts the CO2 figure "many times too high".

"In terms of greenhouse gases, one Google search is equivalent to about 0.2 grams of CO2", stated Google in a blog post.

Google said: "We have designed and built the most energy efficient data centers in the world, which means the energy used per Google search is minimal. In fact, in the time it takes to do a Google search, your own personal computer will use more energy than Google uses to answer your query".