It is now well established that the Earth‘s climate is warming and that the main reason is the accumulation inside the atmosphere of green house gases produced by anthropogenic fossil fuel combustion and change in land use. Global warming has already several visible consequences, in particular increase of the Earth’s mean temperature and of ocean heat content, melting of glaciers, and ice mass loss from the Greenland and Antarctica ice sheets. Ocean warming causes thermal expansion of sea waters, hence sea level rise. Similarly, land ice melt that ultimately reaches the oceans, also causes sea level to rise. In this presentation, we summarize the most up-to-date knowledge about climate change and associated impacts on ocean warming, land ice melt and sea level rise. We highlight the contribution of space observations, in particular from satellite altimetry and space gravimetry, to measure ice sheet mass loss and sea level rise. We also discuss the various causes of sea level rise at global and regional scales and show that in terms of global average, we are now able to close the sea level budget. Finally, we discuss the importance of measuring sea level change at the coast, as well as the many complex processes at work in such regions (due to natural phenomena and anthropogenic forcing) that cause important adverse effects and significant vulnerability to coastal populations.