Is worldwide sea level rise occurring?

There are two sources of evidence which independently concur that sea-level has been rising at about 3.4 mm per year over the past few decades. First, tide gauges across the world give us a picture of how sea-level is changing in relation to the elevation of land masses. In tectonically stable coastlines (like Australia), tide gauges show a consistent increase in sea-level when analysed over inter-decadal time-scales. The second line of evidence is satellite altimeters, which continuously assess the distrance between the ocean surface and the satellite using active sensors. These provide a global picture of sea-level rise consistent with (a) the tide gauge records, corrected for land subsidence and (b) the projections of models relating sea-level to changes in ocean temperature and volume.