Sea level rise from melting glaciers and ice sheets caused by climate warming above pre-industrial levels

The ice sheets in Greenland and Antarctica, combined with glaciers and ice caps around the world, are contributing faster and sooner than expected to global sea level rise. Half a century of observations, physical models, and paleoclimate records suggest that sea level rise will exceed 1 meter this century, but more extreme rates of sea level rise can not be ruled out. I review the current state of knowledge on ice sheet and glacier mass balance, its driving physical mechanisms, their impacts on future sea level rise, and whether the most vulnerable sectors of Antarctica and Greenland have passed, or will soon pass, a point of no return. In several sectors of Greenland and Antarctica, I conclude that multi-meter sea level rise is inevitable, but the rate of sea level rise will depend on how urgently we keep climate warming under control and subsequently bring the climate system back toward pre-industrial levels. To reduce the uncertainties of projecting rapid rates of sea level rise in the coming century, significant research investments will be required, orders of magnitude lower than the cost of adapting to sea level rise, to obtain critical observations and develop more reliable atmosphere-ocean-ice coupled models.