Climate change is a defining issue of our time, a challenge that already affects and will increasingly impact all nations, including some whose very survival is at risk. The complexity of the problem is intrinsically linked with overarching societal issues, such as poverty reduction, economic development and population growth.

After a decade of work on integrating Earth- and satellite-based observing networks, thereby establishing new observation methods that have made a tremendous impact on the way climate change and physical oceanic variability is measured, scientists are once again exploring uncharted waters and looking to set a new course for the future at the OceanObs'09 Conference in Venice, Italy on September 21-25. Ten years ago — at the first conference for a comprehensive ocean observing system — scientists envisioned measuring satellite altimetry of sea-surface height with tide gauges and buoy measurements in order to forecast ocean currents. They brainstormed methods for monitoring changes in temperature and salinity in the Southern Ocean and the South Atlantic which had never been systematically monitored. They also drew up a plan for implementing a global array of temperature and salinity floats that would profile the water column down to a depth of 2,000 meters in real time. The initiatives launched at that conference a decade ago have since provided data that fed the International Panel on Climate Change (IPCC) assessments of human influence on climate change, improved seasonal forecasts crucial for agriculture, hydropower, and storm prediction and provided information invaluable to the lives and safety of mariners.

Internet: <www.unesco.org> (adapted).