Green IT & Sustainability Language Exercises

Carbon-aware computing means scheduling or shifting workloads to times and locations where the electricity grid has a higher share of renewable energy, thereby reducing the carbon emissions associated with running software. In practice you would say "we shift our batch processing jobs to run overnight when the grid carbon intensity is lower" or "our CI/CD pipeline is carbon-aware — it defers non-urgent builds to regions with cleaner energy mixes."

Carbon intensity refers to the amount of CO2 emitted per unit of electricity consumed (gCO2/kWh) and varies by grid, region, and time of day. Carbon footprint is the total volume of greenhouse gas emissions attributable to a specific activity, product, or organisation. In context: "our cloud region has a low carbon intensity because it draws heavily on hydropower" versus "we are working to reduce the overall carbon footprint of our data centre operations by 40% by 2030."

Key metrics and phrases include Power Usage Effectiveness (PUE) for data centres ("our PUE is 1.2, meaning 20% of energy goes to cooling and overhead"), energy per request or per transaction, and hardware utilisation rates ("right-sizing instances improves utilisation and reduces idle energy waste"). The Green Software Foundation defines "software carbon intensity" (SCI) as a methodology to measure emissions per unit of work, often expressed as gCO2e per API call or user session.

Sustainability reports use Scope 1 (direct emissions from owned sources), Scope 2 (indirect emissions from purchased electricity), and Scope 3 (value chain emissions, including cloud provider emissions) classifications from the GHG Protocol. Other standard terms: "net zero," "carbon neutral," "science-based targets (SBTs)," "renewable energy certificates (RECs)," "power purchase agreements (PPAs)," and "verified carbon offsets." Avoid conflating "carbon neutral" (offsetting residual emissions) with "net zero" (eliminating emissions at source).

GreenOps extends FinOps (cloud financial operations) to include environmental impact alongside cost optimisation. The goal is to reduce the carbon footprint and energy consumption of cloud workloads through practices such as workload scheduling, rightsizing, auto-scaling, and choosing lower-carbon regions. In conversation: "our GreenOps practice gives engineers visibility into the carbon cost of each deployment, not just the monetary cost."

Embodied carbon (also called "embedded carbon") refers to the greenhouse gas emissions generated during the manufacture, transport, and disposal of hardware — as distinct from operational emissions during use. Key phrases: "the embodied carbon of a new server is significant — extending hardware lifetime by two years can be more impactful than switching to a greener cloud region," and "we factor embodied carbon into our procurement scorecard alongside price and performance."

Demand shaping means designing software to do less work when the carbon intensity of the grid is high — for example, degrading non-essential features during peak carbon hours. Time-shifting means deferring flexible workloads (batch jobs, model training, backups) to periods of lower carbon intensity. Typical phrasing: "we time-shift our weekly data warehouse rebuild to run on Sunday mornings when wind generation is at its highest" or "the app uses a demand-shaping strategy that lowers image resolution during high-carbon periods."

The Software Carbon Intensity (SCI) score measures the carbon emissions per unit of functional work, expressed as gCO2e/[functional unit]. Unlike an absolute carbon total, SCI is a rate, making it useful for comparing software efficiency across versions or architectures. You would say "our SCI improved from 120 to 85 gCO2e per 1,000 API calls after we optimised the query layer" or "we use SCI as our primary green engineering KPI because it rewards efficiency improvements independent of growth in traffic."

Commonly referenced standards include ISO 14001 (environmental management systems), the GHG Protocol Corporate Standard, the Science Based Targets initiative (SBTi) for corporate emissions reduction commitments, and the EU Code of Conduct for Data Centres. Cloud providers publish their own sustainability reports and offer "carbon footprint tools." The term "RE100" refers to the commitment to source 100% of electricity from renewables. Engineers also reference ENERGY STAR ratings for hardware.

A circular economy approach to IT hardware emphasises refurbishment, reuse, and recycling over disposal. In conversation: "we have a device-as-a-service agreement that returns equipment for refurbishment at end of life," "we prioritise certified refurbished servers for non-critical workloads to reduce embodied carbon," and "our e-waste policy ensures decommissioned hardware is recycled through certified processors rather than going to landfill." The term "asset lifecycle extension" is used when discussing strategies to maximise the useful life of existing equipment.