CO2 Emission Calculation Rules Established for Entire Software Lifecycle

NTT Docomo Solutions (Headquarters: Minato-ku, Tokyo; President & CEO: Tetsuya Mikajiri; hereinafter "NTT Docomo Solutions") participated in the Japan Environment Club's Decarbonization Research Group for the Software Sector as part of its efforts toward decarbonizing the software industry, and together with fellow research group members, examined and established CO2 emission calculation rules covering the entire lifecycle of software products.

These calculation rules enable the assessment of CO2 emissions associated with the procurement, development, operation, and disposal of software products based on the Ministry of Economy, Trade and Industry's "Carbon Footprint Guidelines." This will help promote green procurement and enhance corporate value through Scope 3 calculation and reporting.

Going forward, NTT Group will work to adopt and advance these calculation rules, progressing toward CO2 emission reductions across the entire supply chain.

1. Background

As AI development and adoption accelerate, the risk of increased environmental impact from the ICT industry is growing, and the sustainability of AI technologies and data centers built on software is drawing attention. While software itself does not directly consume physical resources, it indirectly increases energy consumption through the use of cloud services, data centers, networks, and user devices, affecting the overall environmental footprint of the ICT sector. Additionally, social demands for corporate Scope 3 emissions disclosure have intensified in recent years, raising the importance of disclosing CO2 emissions attributable to software products as a basis for procurement evaluation and business decisions.

In March 2024, a Cradle-to-Gate calculation rule (v1.0) was formulated under the Ministry of Economy, Trade and Industry's "FY2023 Project Supporting the Development of Product-Specific Carbon Footprint Calculation Rules for GX Promotion," enabling CO2 emission evaluation at the procurement and development stages. However, since software products are typically used for extended periods after development, evaluating CO2 emissions across the full lifecycle—including operation and disposal—remained a challenge.

2. Outcomes

Through the Japan Environment Club's Decarbonization Research Group for the Software Sector, a Cradle-to-Grave calculation rule was established, expanding the scope of the previous rule—which was limited to the procurement and development stages—to cover the entire lifecycle. Based on the Ministry of Economy, Trade and Industry's "Carbon Footprint Guidelines," this rule enables CO2 emission calculation from procurement and development through operation and disposal, serving as a foundation for formulating strategies to reduce software-attributable CO2 emissions and promoting the greening of the entire supply chain.