The project of Impact of 'Blue Arctic' on Climate at Mid-and-High Latitudes (BlueArc) which was joined by Institute of Atmospheric Physics of CAS and supported by Research Council of Norway kicked off in January 2011. The fund for this project is 8 million. The observational data, reanalysis data and satellite data have all revealed that in the past 30-plus years, the Arctic sea ice area has been decreasing, and such decrease tends to intensify, and that it reached the minimum value in September 2012 since satellite observation data were available. By combining the observational data, reanalysis data and numerical model, this project studies the feedback effect of the Arctic sea ice in the climatic change at high latitudes.