Ever since hurricane Katrina, it has been an open secret: the old, the poor and immigrants suffer most when natural disasters hit the US.

When the first comprehensive report in years to examine energy use by computer servers was published in February 2007, it was greeted with surprise by industry insiders. Jonathan Koomey, a staff scientist at Lawrence Berkeley National Laboratory in California, found that worldwide power consumption by servers had doubled between 2000 and 2005. "Everyone thought CO2 emissions were a problem for transportation and big energy," says Bill St Arnaud of Canarie, Canada's internet development organisation in Ottawa, Ontario.