Did you know that

to global warming just by surfing the Internet? Some experts estimate that a single query in a search engine may use

a small light bulb does in five minutes. Others disagree, and counter that driving a car for just one kilometer

as 1,000 searches on the web, and that eating a hamburger is equivalent to

. And, of course, some Internet activity clearly saves energy. For example, if you buy all your food online, you don't have to

any more.

Surfing the web may use only a tiny amount of energy compared to other activities, but when all the Internet activity in the world is taken into account, it soon adds up. Some environmentalist estimate that

up to 10 percent of the world's total energy consumption, although as computers get faster, that total may well decrease. In the USA people spend an average of around

, with teenage girls the highest users. But that still seems little compared to the 127 hours that the average American spends

every month. So is the net green? Not very, but it's a lot greener than other common activities, and it should get greener as technology improves.