Negative values (e.g., in C5, C6) represent 
an increase in emissions. The modelled GHG emissions in 2019 are 55 [53–58] GtCO2-eq, thus within the uncertainty ranges of estimates for 2019 emissions [53-66] GtCO2-eq 
(see 2.1.1). 
4 Emissions milestones are provided for 5-year intervals in order to be consistent with the underlying 5-year time-step data of the modelled pathways. Ranges in square 
brackets underneath refer to the range across the pathways, comprising the lower bound of the 5th percentile 5-year interval and the upper bound of the 95th percentile 
5-year interval. Numbers in round brackets signify the fraction of pathways that reach speciﬁc milestones over the 21st century. Percentiles reported across all pathways in 
that category include those that do not reach net zero before 2100.
5 For cases where models do not report all GHGs, missing GHG species are inﬁlled and aggregated into a Kyoto basket of GHG emissions in CO2-eq deﬁned by the 100-year 
global warming potential. For each pathway, reporting of CO2, CH4, and N2O emissions was the minimum required for the assessment of the climate response and the assignment 
to a climate category. Emissions pathways without climate assessment are not included in the ranges presented here. See WGIII Annex III.II.5. 
6 Cumulative emissions are calculated from the start of 2020 to the time of net zero and 2100, respectively. They are based on harmonised net CO2 emissions, ensuring 
consistency with the WG I assessment of the remaining carbon budget. {WGIII Box 3.4, WGIII SPM Footnote 50}