Changes in Local Sea Level (LSL) are likely to be one of the major climate change impacts, requiring mitigation strategies with severe societal and economic consequences or expensive coastal protection measures. In many countries including the U.S., decision makers are facing decisions of whether to burden national economies with costs for coastal protection, or to risk major disasters. The challenging decision to rebuild coastal infrastructure devastated by storm surges or to abandon cities (for example, New Orleans) or island nations (for example, the Maldives) under increasing risks from storm surges and rising LSL needs to be informed by an understanding of the uncertainties. Today's planning decisions will have long term implications for mitigating the potential of a slowly developing disaster caused by LSL rise.