PEBBLE ACADEMY · Methodology
Beyond the Annual Number
Traditional corporate carbon accounting produces one big number a year. It's useful for ESG reports and not much else. It can't tell a product manager whether shipping a new feature was a net positive, or a CFO whether the green data center was actually green at the unit economics level.
Unit-based carbon accounting fixes that by attributing emissions to specific units of value — per inference, per active user, per training run, per delivered package.
Why Engineering Teams Care
When emissions are reported per unit, they enter the same headspace as latency, error rate, and unit cost. Engineers are very good at optimizing what they can see in dashboards. They are not good at optimizing what shows up only in a sustainability report.
The Mechanics
Unit-based accounting requires three pieces in place: an activity-level emissions feed (Scope 2 cloud energy at minimum), a clear definition of "unit" (an inference, a transaction, a job), and a way to map them to each other — usually via tags or labels on the underlying compute.
Once those are in place, the math is straightforward: total emissions for a window, divided by units delivered in that window.
Where It Goes Next
Mature programs start using unit-based metrics inside their pricing models, vendor scorecards, and product roadmaps. "Green per unit" becomes a tracked metric alongside cost per unit — and the two often correlate strongly, which makes the business case obvious.