Developed by the Boston Consulting Group (BCG) on behalf of the Global e-Sustainability Initiative (GeSI), an international partnership of ICT companies, the tool is designed to help promote smart motors, logistics, buildings and grids as routes to decarbonisation.

It takes a life-cycle assessment approach and considers both the ICT sector's own emissions and emissions it indirectly saves or causes. Examples of the former are ICT products and services reducing energy, travel or material use. An example of the latter is increased energy use at home as a result of telecommuting.

The methodology only assesses the factors affecting emissions that have the greatest impact on a business-as-usual scenario. In the telecommuting example, higher energy use at home and reduced use of cars and office buildings are taken into account. In a large-scale project, reduced use of transport infrastructure and office buildings would also be considered.

In one of six case studies launched with the new tool, the small-scale telecommuting calculation delivers a net CO2 saving of 14.3 kilotonnes CO2 equivalent per year. That number may not be 100% accurate, the authors say, but shows whether the overall effect is positive or negative and gives a decent scale of magnitude.

GeSI's new tool is intended to help make a climate case for ICT products and services. It also allows policymakers to justify incentives for their deployment. It follows on from GeSI's "Smart 2020" report in 2008, which laid out the potential for ICT technologies to reduce carbon emissions.