It was on April 17th, 1889 when the first teleseismic record of an earthquake near Japan was recorded at the Geodetic Institute in Potsdam. Since then geodesy continuously contributed to monitor the Earth surface and processes with different techniques, today with applications like GPS or interferometric SAR. The devastating tsunami in 2004 in the Indian Ocean clearly demonstrated the need of a more integrated and near real-time geodetic data processing and analysis. With different techniques like GPS or tide gauge measurement geodesy has demonstrated the ability to significantly contribute to establishing an early warning system infrastructure. In the past three years steps have been taken to develop real-time applications allowing to closely monitoring e.g. volcanoes, earthquake processes and tsunami propagation. In many areas the Earth surface is now monitored with GPS with millimeter accuracy, with GPS seismology, or the ocean surface with a global network of GPS-equipped coastal sea level stations distributing data in near-real time. Moreover, new applications are under development, like GPS-equipped offshore buoys, GPS altimetry or the detection of tsunami signatures in GPS ionospheric measurements, to mention only a few.
However, for all of these techniques a backbone is needed, which will be established through the different components of GGOS. The global GGOS infrastructure with e.g. real-time GPS stations and processing centers will establish a significant contribution by the provision of the stable global reference system, precise orbits and clocks. New ground and space-based applications will be developed bringing geodesy more and more into the focus of early warning systems.