The provided context does not give a strict standalone definition of “carbon budget,” but it places the term within climate-mitigation planning. In this usage, a carbon budget can be understood as the remaining amount of CO₂ emissions that can be released while still keeping warming within a target such as 1.5°C. It is therefore closely tied to the balance between emissions reduction and carbon removal. The passages emphasize that carbon removal is not a substitute for cutting emissions; rather, it is a complementary tool for offsetting residual emissions that are difficult to eliminate, such as those from industry and aviation, and for helping lower temperatures over the long term.
The context also shows why the concept matters. Multiple studies cited there suggest that achieving the 1.5°C goal may require large-scale negative emissions later this century, with annual removal needs on the order of 7–10 Gt of CO₂ by mid-century and even more by 2100 in some scenarios. By contrast, current human carbon removal is only about 2 Gt per year, mostly from forests and soils, while advanced technologies remain at a very early stage. DAC and BECCS are described as potentially scalable and durable, but they face major constraints in cost, energy demand, storage capacity, and social acceptance. In this sense, the carbon budget is not just a numerical limit; it is a planning framework linking emissions, removal, and long-term climate stabilization.