Both the melting of ice and the thermal expansion of warmer seawater contribute to sea level rise. The ice sheets of Greenland and Antarctica are contributing to rising sea levels faster than was anticipated ten years ago. Since satellite measurements began the yearly average rise has been 3.4 millimetres per year. During the 2000 years before the industrial era, the sea level rose an average of 0.2 millimetres per year, a tiny fraction of what we now see is happening.
The change around the globe is not necessarily the same at regional and local levels. Water mass, vertical land movements and dynamic effects resulting from oceanic circulation, wind pressure patterns and ocean water density all cause regional variations. Projected scenarios of sea level rise have uncertainties. What is clear is that higher temperatures will cause ocean water to expand and ice caps will continue to melt.
Warmer seas also have an impact on precipitation worldwide. During the last 100 years the precipitation on earth has increased about 20 percent. The occurrence of extreme weather events has risen dramatically during the last 60 years. The change in weather patterns is linked to higher water and air temperatures forming more vapour and clouds. The consequences look similar on all continents, heavier rains, storms and extremes like cyclones and hurricanes. Rising sea surface temperatures has been identified as the leading cause. More extreme weather events and precipitation changes will most likely have a bigger impact on human society and ecosystems than actual changes in temperature. But the continued rise in temperature will have huge consequences for the world's coastal and low lying areas