Chapter 01 · Climate & transitionClimate & Greenhouse Gas Emissions
Carbon stock
Definition
The quantity of carbon contained in a "pool" or reservoir at a specified time, typically expressed in tonnes of carbon per hectare or total tonnes. For forests, the IPCC framework recognises five pools: above-ground biomass, below-ground biomass, dead wood, litter and soil organic matter. Changes in stocks over time quantify emissions or removals.
References
Supports definition and framing.
Supports definition and framing.
Overview
What it means
Stock is the balance-sheet item; flux is the transaction. Land-based climate accounting (inventories, REDD+, forest carbon credits) fundamentally works by measuring stock change: a forest credit is issued only when the stock demonstrably grows relative to a baseline. Stock measurement combines field plots, remote sensing and models, with soil organic carbon often the largest and hardest pool to measure.
Disturbance — fire, logging, drought — converts stock to emission, which is why permanence and reversal buffers dominate land-credit methodology.
How it is used
National GHG inventories report stock changes in the LULUCF sector; carbon methodologies set measurement protocols per pool; conservation finance values high-stock ecosystems (old-growth forests, peatlands, mangroves) as irrecoverable-carbon priorities.
Why it matters
Carbon stocks are what climate policy on land actually protects; stock-change measurement quality determines whether forest carbon claims are real or estimated away.