Figure 2

Comparison of FFGHG CO₂-equivalent emissions from TD and BU on the global scale from 1970 to 2021 for (a) total FFGHGs, (b) SF₆, (c) NF₃, (d) total PFCs, (e) CF₄, (f) C₂F₆, (g) C₃F₈, and (h) c-C₄F₈. Unit: million tons CO₂-equivalent per year (Mt CO₂-eq yr⁻¹).The global TD emissions of individual FFGHG were from Simmonds et al., 2020¹ (SF₆ emissions from 1978 to 2018), Say et al., 2021¹⁹(CF₄/C₂F₆/C₃F₈ emissions from 2005 to 2019), Mühle et al., 2019&2022^23,24(c-C₄F₈ emissions from 1973 to 1989¹⁵ and from 1990 to 2020²⁷), updates of Rigby et al., 2014¹⁶ (NF₃ emissions from 1979 to 2017 and CF₄/C₂F₆/C₃F₈ emissions before 2005), and WMO, 2022¹⁸ (SF₆/NF₃/CF₄/C₂F₆/C₃F₈ emissions in 2020). The annual global TD total FFGHG emissions were the sum of six FFGHG global TD emissions. The purple shading area represents the 16th–84th percentile range from the AGAGE 12-box model. The hollow squares mean that these values were extrapolated from the recent 5 years’ emissions. FFGHG emissions in the United Nations Framework Convention on Climate Change (UNFCCC) are obtained from the following website: https://di.unfccc.int/flex_annex1 and https://di.unfccc.int/flex_non_annex1. FFGHG emissions in the Emissions Database for Global Atmospheric Research (EDGAR) are from EDGAR v4.2³⁷ (1970–1989) and EDGAR v7.0³⁸ (1990–2021). FFGHG CO₂-equivalent emissions in US Environmental Protection Agency (EPA) were from Global Non-CO₂ Greenhouse Gas Emission Projections & Marginal Abatement Cost Analysis: Methodology Documentation³⁹. Note that EPA only provided total PFC emissions instead of individual PFC emissions. All TD and BU data is accessed before 2023-11-10.