The complacency with which Man inhabits continent-ocean margins or plate boundaries is based on the assumption that sea level rise and periodic seismicity are acceptable risks. The forecast of future sea level or future seismicity is essential for informed assessment of these risks. The historical data from which forecasts may be derived are in each case of limited antiquity and uneven spatial distribution. Developments in space geodesy and crustal deformation metrology in the past two decades offer the means to acquire a homogeneous global data set for monitoring relative vertical and horizontal motions of the Earth's surface to within several millimeters. These new tools are reviewed in terms of their application to forecasting trends in sea level rise and forecasting damaging earthquakes.