Quantifying non-CO2 contributions to remaining carbon budgets

Abstract The IPCC Special Report on 1.5 °C concluded that anthropogenic global warming is determined by cumulative CO 2 emissions and the non-CO radiative forcing level in decades prior to peak warming. We quantify this using -forcing-equivalent (CO -fe) emissions. produce an observationally constrained estimate of Transient Climate Response carbon Emissions (TCRE), giving a 90% confidence interval 0.26–0.78 °C/TtCO , implying remaining total -fe budget from 2020 350–1040 GtCO -fe, where changes take up 50 300 -fe. Using central estimate, budgets are 640, 545, 455 for 33, or 66% chance limiting °C. discuss impact GMST revisions contribution mitigation budgets, determining reporting alternative definitions GMST, displaying contributions two-dimensional presentation, offers most transparent approach.