The MCC Carbon Clock shows how much CO2 can be released into the atmosphere to limit global warming to a maximum of 1.5°C and 2°C, respectively. With just one click, you can compare the estimates for both temperature targets and see how much time is left in each scenario.
As to the scientific basis of the carbon clock, we exclusively draw on data from the Intergovernmental Panel on Climate Change (IPCC), which represents the verified state of research. The IPCC last updated its estimate of the remaining carbon budget in summer 2021, with the presentation of the first part of its Sixth Assessment Report.
According to report (see here, table SPM.2), on the 1.5 degree Celsius target, the atmosphere can absorb, calculated from the beginning of 2020, no more than 400 gigatonnes (Gt) of CO2 if we are to stay below the 1.5°C threshold. Annual emissions of CO2 – from burning fossil fuels, industrial processes and land-use change – are estimated to be 42.2 Gt per year, the equivalent of 1,337 tonnes per second. With emissions at a constant level, the budget would be expected to be used up in less than eight years from now. The budget for staying below the 2°C threshold, for its part, of 1,150 Gt, would be exhausted in about 25 years. The budgets are calculated in such a way that it is highly likely that the respective temperature target will be met, that is in two thirds of the climate scenarios examined.