The digital transformation has direct and indirect effects on greenhouse gas (GHG) emissions. Direct effects are caused by the production, use and disposal of information and communication technology (ICT) hardware. Indirect effects include the changes to patterns of production and consumption in other domains. Studies quantifying both effects often conclude that net effects (indirect minus direct effects) can lead to a significant GHG emission reduction. We revisited a study by Accenture on ICT’s GHG abatement potential in Switzerland by reassessing the main assumptions. Our results confirm that ICT has the potential to reduce GHG emissions in Switzerland, especially in the building, transport and energy domains. However, our results also suggest that the potential is smaller than anticipated and that exploiting this potential requires targeted action. Reasons for differences among these results (and the results of similar other studies) are: degrees of freedom in the assessment methodology, selection of ICT use cases, allocation of impacts to ICT, definition of the baseline, estimation of the environmental impact, prediction of the future adoption of use cases, estimation of rebound effects, interaction among use cases, and extrapolation from use case to societywide impacts. We suggest addressing these methodological challenges to improve comparability of results.