In recent years the confluence of socio-political trends towards environmental responsibility and the pressing need to reduce run-the-engine (RTE) costs has given birth to a nascent discipline of green information technologies (green IT). There has been some recent literature on green data centres, but one has seen less documentation related to green networks. Networking typically represents 5 per cent of the total power consumption of an enterprise IT operation; however, for service providers such as fixed line network operators, mobile operators and cable TV providers, the power usage is quite substantial. The consumption of energy by enterprises and service providers drives greenhouse gas (GHG) emissions. Collectively the entire IT/networking field is also known as the information and communications technology (ICT) space. As an industry, the ICT sector currently contributes in the range of 2-2.5 per cent of the global GHG emissions but this figure is likely to grow as IT and networking become more widely deployed. Fortunately, IT and networking can enable significant reductions of emissions in other sectors of the economy; by enabling other sectors to improve and automate their operations, the industry could help to reduce global emissions by as much as 15 per cent by 2020. This can be accomplished, for example, with the replacement of goods and services with virtual equivalents, and by the introduction of sensing, telecommand and telecommunications technology, all of which are poised to foster energy efficiency. This paper extends the techniques that have been identified in the recent past for green IT and data centres to the networking environment and looks at opportunities for incorporating green principles in the intranet, extranet and internet; it also covers the service provider and telecommunications carrier space.