What Is the ICT Carbon Footprint?

The ICT carbon footprint is the total quantity of greenhouse gas emissions, expressed in carbon dioxide equivalent (CO2e), attributable to the production, operation, and end-of-life disposal of information and communications technology hardware, software, and services. It encompasses direct energy consumption during use (operational emissions), the energy and materials embedded in manufacturing and logistics (embodied emissions), and the emissions associated with waste processing. Quantifying the ICT carbon footprint has become a central concern for climate policy and corporate sustainability planning, given the sector's significant and growing share of global electricity demand.

Peer-reviewed estimates place ICT's share of global greenhouse gas emissions at approximately 1.8 to 2.8 percent of the total, with some lifecycle-expanded estimates reaching as high as 3.9 percent. Research published in peer-reviewed journals, including work tracked through arxiv.org on ICT sector greenhouse gas emissions, highlights that the sector consumed roughly 1,000 TWh of electricity globally in 2023. Connected devices such as smartphones account for the largest share of emissions, followed by data transmission networks and data centers.

Emission Sources and Lifecycle Scope

ICT emissions arise across three lifecycle stages. Manufacturing emissions, also called embodied carbon, include the extraction of raw materials (rare earth elements, silicon, copper), semiconductor fabrication, assembly, and global shipping. For mobile devices, embodied carbon can represent 50 percent or more of the device's total lifetime emissions, because manufacturing a new smartphone is energy-intensive relative to the energy consumed during its operational years. Operational emissions arise from the electricity consumed by data centers, network infrastructure, and end-user devices during normal use. For data centers, embodied carbon is roughly 25 percent of total lifetime emissions, while operational energy dominates. End-of-life emissions arise from improper disposal: unregulated e-waste processing, including open burning of cables to recover copper, releases toxic compounds and contributes greenhouse gases.

Measurement and Reporting Challenges

A consistent challenge in quantifying the ICT carbon footprint is the absence of agreed-upon measurement boundaries and reporting standards. Companies often disclose power usage effectiveness (PUE) for data centers without reporting the actual electricity consumed or the carbon intensity of the grid supplying that electricity. Geographic variation in grid carbon intensity is large: values range from approximately 29 gCO2e per kilowatt-hour in hydropower-heavy grids to over 700 gCO2e per kilowatt-hour in coal-heavy grids. Supply chain emissions are difficult to apportion because devices cross many national boundaries during manufacturing. The IEEE Sustainable ICT initiative has developed standards for ICT environmental impact assessment that address energy efficiency, greenhouse gas accounting, and e-waste, providing frameworks for more consistent reporting across the industry.

Mitigation Strategies

Reducing the ICT carbon footprint requires action across the full lifecycle. On the operational side, shifting data center and network infrastructure to renewable energy sources has driven measurable gains: while ICT electricity consumption has grown by two to three percent annually since 2020, the expanded share of renewable energy has kept total GHG emissions roughly stable or declining in some estimates. Extending device lifetimes reduces the frequency of manufacturing cycles and the associated embodied emissions; analysis consistently shows that prolonging a device's useful life is one of the most effective per-device interventions. Software efficiency improvements, such as reducing the compute required per inference in machine learning applications, can reduce operational demand. The ITU-T Focus Group on Environmental Efficiency coordinates international work on methodology and standards for ICT energy and emissions measurement.

Applications

ICT carbon footprint analysis has applications in a range of fields, including:

• Corporate sustainability reporting and science-based targets
• Green procurement policies for government and enterprise ICT
• Data center site selection based on grid carbon intensity
• Product environmental declarations and eco-labeling schemes
• Climate policy modeling of the digital economy's emissions trajectory