s154.
The internet’s reliance on a relatively small number of hubs—and the implications of this for its ability to cope with breakdown—was pointed out in 2002, as reported, for instance, in Bobbie Johnson, “Web Providers Must Limit Internet’s Carbon Footprint, Say Experts”, The Guardian, 3 May 2009. It is discussed in more detail in Barabási (2002), chapter 11. For additional references on this fast-moving subject, look for “critical infrastructure”, such as Ted G. Lewis (2006), Critical Infrastructure Protection in Homeland Security: Defending a Networked Nation, Wiley-Blackwell; and the series Critical Infrastructure Protection, US Congressional Sales Office. The source for computers accounting for 2 percent of carbon emissions is Phil McKenna, “Can We Stop the Internet Destroying our Planet?”, New Scientist, 2637, 3 January 2008 (citing a report from UK charity Global Action Plan). For the energy consumption and carbon emissions of the internet, see, e.g., Professor Jaafar Elmirghani’s ongoing projects and research at Leeds University, or Duncan Clark and Mike Berners-Lee, “What’s the carbon footprint of . . . the internet”, The Guardian, 12 August 2010.