Advanced Microwave Scanning Radiometer 2 (AMSR2) loaded on Global Change Observation Mission–Water (GCOM-W) satellite, “Shizuku,” revealed that the area of global sea ice reached a "minimum value" on January 14, 2017. This is the lowest amount recorded since satellite observations began in 1978; the previous minimum value was recorded in November 2016. Observations revealed global sea ice covered 16,219,388 km2 on January 25, 2006, but this area had shrunk to 15,716,332 km2 by February 9, 2017, equaling a reduction of approximately 500,000 km2 (an area approximately equivalent to the size of Thailand).

Figure 1. Annual seasonal changes in area of global sea ice for both Arctic and Antarctic. Red circle indicates minimum value. These long-term sea ice data have been recorded since 1978 and were created using AMSR2 and other microwave radiometer data.

 

The area of sea ice in the Arctic Ocean had reportedly been shrinking prior to November 2016, but it then began to slowly increase during the ice formation period. However, it then began to shrink again and reached a minimum in February 2017.

Figure 2. Distribution of sea ice in Arctic Ocean on January 14, 2017. Orange line indicates average sea ice edge distribution during the 2000s.
 

The sea ice area in the Antarctic Ocean had been increasing, but it began to decline sharply in (approximately) October 2016 and reached a minimum value in February 2017. This trend has now continued since 2017, and the current remaining area is very small.

 

Figure 3. Distribution of sea ice in Antarctic Ocean on January 14, 2017. Orange line indicates average sea ice edge distribution during the 2000s.

Areas of global sea ice undergo considerable annual changes; this influences the amount of light available within the water. This subsequently affects plankton growth, the food chain, and ultimately impacts human society. In addition, the feedback from ice albedo affects the amount of water vapor transported, which thus provokes major climate changes. Utilization of areas where ice is decreasing is being proposed, such as development of an Arctic sea route.

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