Sea level rise is an important aspect of future climate change because, without upgraded coastal defences, it is likely to lead to significant impacts. Here we report on several aspects of sea level rise that have implications for the avoidance of dangerous climate change and stabilisation of climate. If the Greenland ice sheet were to melt it would raise global sea levels by around 7m. We discuss the likelihood of such an event occurring in the coming centuries and the possibility that it might be irreversible. We also discuss the time scales controlling sea level rise and estimate how long after atmospheric greenhouse gas concentrations or global temperature have been stabilised that coastal impacts will stop increasing.