Conductivity, temperature, and depth data collected during the summers of 2003 and 2008 were used to study upper-ocean (top 200 m) heat content in the Canada Basin. The variation of heat content with depth,heat content differences between the summers, principal driving factors, and horizontal spatial scale differences were analyzed. A catastrophic reduction of sea ice cover in the Canada Basin was evident in 2008 by comparison with 2003, suggesting that more solar radiation was absorbed in the upper ocean during the summer of 2008. The sea ice reduction produced more freshwater in the upper ocean. Thus, seawater properties changed. The study shows that the huge reduction of sea ice would result in two changes-widespread warming of the upper ocean,and the depth of Pacific inflow water in the basin increased substantially. Near-surface temperature maximum(NSTM) water was also analyzed as an indicator of Arctic Ocean warming. Conductivity, temperature, and depth data collected during the summers of 2003 and 2008 were used to study upper-ocean (top 200 m) heat content in the Canada Basin. The variation of heat content with depth, heat content differences between the summers, principal Driving factors, and horizontal spatial scale differences were analyzed. A catastrophic reduction of sea ice cover in the Canada Basin was evident in 2008 by comparison with 2003, suggesting that more solar radiation was absorbed in the upper ocean during the summer of 2008. The sea The study shows that the huge reduction of sea ice would result in two changes-widespread warming of the upper ocean, and the depth of Pacific inflow water in the basin increased Near-surface temperature maximum (NSTM) water was also analyzed as an indicator of Arctic Ocean warming.