  Despite the new Corporate Sustainability Reporting Directive from the
European Union, which presses large enterprises to be more transparent about
their GHG emissions, and though large technology- or advisory firms might
peddle otherwise, there are plenty of challenges ahead when it comes to
measuring GHG emissions from IT activities in the first place. This paper
categories those challenges into 4 categories, and explains the current status,
shortcomings and potential future research directions. These categories are:
measuring software energy consumption, server overhead energy consumption,
Energy Mix and emissions from embodied carbon. Next to that, various non-profit
and open-source initiatives are introduced as well as a mathematical framework,
based on CPU consumption, that can act as a rule-of-thumb for quick and
effortless assessments.
