The amount of carbon dioxide that we can still emit while limiting global warming to a given target is called the "remaining carbon budget," and it has become a powerful tool to inform climate policy goals and track progress towards net-zero emissions targets.
This carbon budget is like a fixed financial budget: there is a cap on total allowable expenses over time, and excess spending in the near term requires deceased spending in the future. Similarly, the remaining carbon budget is a fixed total quantity of future emissions that is small enough to limit global temperature increases before they exceed our climate targets.
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