This data set consists of two simulations conducted with the Norwegian Earth System Model. These are an extension of the CMIP5 1% CO₂ ramp-up (1pctCO2), simulating a 1% CO₂ ramp-down until preindustrial CO₂ concentrations are reached plus a 60 year extension at constant CO₂ levels. The model version is the same as used for CMIP5 and is documented in Tjiputra et al. 2013. For further information, please contact (jorg DOT schwinger AT uni DOT no) or (jerry DOT tjiputra AT uni DOT no).