Is Anthropogenic Global Warming Accelerating?

Abstract Estimates of the anthropogenic effective radiative forcing (ERF) trend have increased by 50% since 2000 (from +0.4 W m ?2 decade ?1 in 2000–09 to +0.6 2010–19), majority which is driven changes aerosol ERF trend, as a result emissions reductions. Here we study extent observations climate system agree with these assumptions. We use large ensemble from IPCC’s Sixth Assessment Report (AR6) attribute contributions global mean surface temperature (GMST), top-of-atmosphere flux, and optical depth observations. The GMST has +0.18°C +0.35°C 2010–19, coinciding warming rising +0.19°C +0.24°C 2010–19. This, well observed trends fluxes depths, supports claim an aerosol-induced temporary acceleration rate warming. However, all three observation datasets additionally suggest that smaller are compatible 2000, flux significantly influenced internal variability over this period. A zero-trend-change scenario results much but poorly represented AR6’s ensemble. Short-term difficult verify using observations, so caution required predictions or policy judgments depend on them, such estimates current time remaining to, outstanding carbon budget consistent with, 1.5°C Further systematic research focused quantifying early identification deceleration required.