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 two 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. We also examine the time scales associated with sea-level rise and demonstrate that long after atmospheric greenhouse gas concentrations or global temperature have been stabilised coastal impacts may still be increasing.