Green communication systems and, in broader terms, green information and communications technologies have the potential to significantly reduce greenhouse gas emissions worldwide. This article provides an overview of two issues related to achieving the full carbon abatement potential of ICT. First, green communications research challenges are discussed, notably as they pertain to networking issues. Various initiatives regarding green ICT testbeds are presented in the same realm in order to validate the “green performance” and functionality of such greener cyber-infrastructure. Second, this article offers a description of ongoing international efforts to standardize methodologies that accurately quantify the carbon abatement potential of ICTs, an essential tool to ensure the economic viability of green ICT in the low carbon economy and carbon credit marketplace of the 21st century.