Carbon budget
Carbon budget is a cumulative amount of carbon dioxide emissions consistent with limiting warming to a specified level and likelihood. Applying Carbon budget requires a stated emissions scope, inventory boundary, baseline, energy system, and assessment horizon. Those choices determine how Carbon budget can be compared or acted upon.
In simple terms
In practical use, Carbon budget is a cumulative amount of carbon dioxide emissions consistent with limiting warming to a specified level and likelihood. For Carbon budget, the label organizes a condition or relationship but does not by itself demonstrate performance or compliance within a declared emissions scope, inventory boundary, baseline, energy system, and assessment horizon. Its size depends on the temperature limit, probability, starting date, treatment of non-carbon-dioxide forcing, and Earth-system response. Carbon budget connects with Global warming potential and Climate change; each can affect its application without sharing its definition. The candidate link between Carbon budget and Energy performance contract remains a separate expansion question supported here by Intergovernmental Panel on Climate Change.
Why it matters
Carbon budget matters because decisions about it determine which emissions enter an inventory, which transition option appears credible, and how progress is compared over time. A defensible use of Carbon budget therefore exposes its boundary, method, evidence, responsible actor, and uncertainty before a conclusion is accepted. That discipline keeps Global warming potential and Climate change from being treated as proof of Carbon budget when their criteria, scope, or results differ.
Example
An emissions and energy team evaluates Carbon budget for a defined decision and records the relevant emissions scope, inventory boundary, baseline, energy system, and assessment horizon. For Carbon budget, the team uses cited material from Intergovernmental Panel on Climate Change to frame the decision and distinguish the idea from adjacent concepts, documenting the period, data, assumptions, and comparison with Global warming potential. It treats Climate change and Energy performance contract as separate questions rather than proxies for Carbon budget.
How it differs
Global warming potential
Carbon budget is a concept; Global warming potential has a different function. Evidence for Global warming potential does not establish Carbon budget unless both sets of applicable criteria are met.