Carbon budget

A carbon budget refers to the finite quantity of carbon dioxide (CO2) that can be emitted before reaching a limit on the increase in average temperature (e.g., 1.5 degrees Celsius or well below 2 degrees Celsius). A carbon budget can be global, in which case it would provide the finite quantity of carbon dioxide that can be emitted globally before reaching a limit on temperature increases. A carbon budget can also be national, in which case it would provide the finite quantity of carbon dioxide that can be emitted nationally before reaching the limit on the state’s permitted CO2 emissions. Generally, national carbon budgets are derived by reference to a global carbon budget – meaning that a national carbon budget refers to a particular state’s portion of a global carbon budget, based on its population size, historical emissions, and/or some other metric.