Sea ice cover in the Arctic Ocean reached an annual summer low in September. At 1.82 million square miles, it was 579,000 square miles smaller than the 1981-2010 average, according to the National Oceanic and Atmospheric Administration.
The ice peaks every March and its minimum every September.
According to the National Snow and Ice Data Center, the amount of ice that survives the summer melt season has declined 13% per decade from the 1981-2010 average.
The shrinking Arctic sea ice is linked to the phenomenon known as Arctic amplification, which NOAA says is warming more intensely in the Arctic than in the rest of the world.
Arctic amplification applies to the current scientific understanding of the Earth’s climate system and to model projections of global warming caused by greenhouse gas emissions. Multiple factors are contributing to the amplification of the Arctic, and the loss of sea ice is one of them.
The white surface of the pack ice reflects up to 80% of incoming sunlight, deflecting additional energy away from the planet. With less ice present, the dark ocean surface absorbs much more solar energy, resulting in further warming of the sea surface and the overlying atmosphere, which in turn results in melting. increased ice, and the cycle continues.
Scientists are studying the effects of this feedback loop to help them understand and predict how decreasing sea ice and snow cover will affect the global climate system.
The loss of sea ice affects marine mammals such as walruses, polar bears and seals, and disrupts the food supply of Arctic residents.
Satellite measurements, which began in the late 1970s, have reported a decline in sea ice every year.