The greenhouse gas concentration that is consistent with the 2 degree objective is between 430 and 480 part per million of CO2 equivalent. The global carbon budget will only be calculated for CO2; we make assumptions regarding the contributions of other greenhouse gases, other climate changing factors like aerosols and albedo, the timing of CO2 emissions reductions, and the sensitivity of the climate to CO2 emissions and climate forcing. Given all of this, the carbon budget by the end of the century is within the range of 630 to 1180 billion tons of CO2. Countries’ emissions reduction objectives are to the best to the year 2050, and we need to be able to assess them. Many emissions scenarios are based on the idea of negative emissions during the second half of the century, which means using technology like bio-energy combined with carbon capture and sequestration (CCS). The feasibility and advisability of this is still very much under debate. Each step of CCS is a known and feasible technology, but it is unclear if it is safe and sustainable. We can define global carbon budget for just one sector, for example the fossil fuel industry, by making assumptions about other sectors. This video is part of the module The 2-Degree Carbon Budget.
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