Less Arctic ice means higher risks, experts warn   The animation shows changing sea ice extent and concentration from 12 March to 24 September 2007. These weekly and bi-weekly Arctic charts are based on the analysis of observations from a diverse number of satellite missions including ESA's Envisat, CSA's RADARSAT-1, NASA's QuikSCAT, DMSP, and NOAA. Satellites for monitoring, modelling     Envisat ASAR mosaic of the Arctic Ocean for early September 2007, clearly showing the most direct route of the Northwest Passage open (orange line) and the Northeast passage only partially blocked (blue line). The dark grey colour represents the ice-free areas, while green represents areas with sea ice.   Operational ice experts from Europe and North America gathered at ESRIN, ESA’s Earth Observation Centre in Frascati, Italy, for a five-day conference to discuss the state of the polar regions. Release date: 8 June 2010