Already committed future warming & climate change The radiative heat forcing of today's atmospheric GHGs (above) commits the world to a global warming of 1.5C by 2030-2040 (IPCC AR5 WG1 Figure 11.6) and full equilibrium warming of 2.0C. 'The current RF(radiative forcing) from GHGs maintained indefinitely (i.e., the commitment from constant greenhouse gas concentrations) would correspond to approximately 2°C warming.' (IPCC AR5 WG1 220.127.116.11)
Since 2000 atmospheric concentrations of all three main GHGs are accelerating - confirmed by BAMS July 2915 (see recent series page). Radiative heat forcing is also accelerating.