It is known that carbon dioxide emissions cause the Earth to warm, but no previous study has focused on examining how long it takes to reach maximum warming following a particular CO 2 emission. Using conjoined results of carbon-cycle and physical-climate model inter-comparison projects (Taylor et al 2012 , Joos et al 2013 ), we find the median time between an emission and maximum warming is 10.1 years, with a 90% probability range of 6.6–30.7 years. Figure 1 shows Temperature increase from an individual emission of carbon dioxide (CO 2 ). Time series of the marginal warming in mK (=milliKelvin = 0.001 K) per GtC (=10 15 g carbon) as projected by 6000 convolution-function simulations for the first 100 years after the emission. Maximum warming occurs a median of 10.1 years after the CO 2 emission event and has a median value of 2.2 mK GtC −1 . The colors represent the relative density of simulations in a given region of the plo...