“Changes in the ice are part of a larger “cascade effect,” as Webster describes it, in which delayed winter ice growth leads to thinner ice, which melts more easily in the summer months compared to older, thicker sea ice. This creates more open ocean.
This transformation contributes to both regional and global warming. Where a white sea ice surface would have reflected sunlight, the dark water absorbs heat, which further reduces ice growth. This change in albedo (or reflectivity) on sea and land in the Arctic is one of the main reasons the region is heating at twice the global average rate, according to the National Oceanic and Atmospheric Administration’s 2019 Arctic Report Card. According to the recent Nature Communications study, it will also be a significant contributor to global warming.
Near Greenland — which holds a massive ice sheet — the warming loop set off by sea ice loss has a minor effect on its warming, but not a substantial effect on the ice sheet itself, researchers found in a 2019 study in Geophysical Research Letters.
The sea ice shift could also impact seasonal weather, potentially intensifying extreme weather. However, Labe says the issue requires further research. “Scientists are actively studying the connections between Arctic sea ice loss and wintertime weather patterns in North America, Europe, and Asia,” he said. “However, these relationships remain highly uncertain in the scientific literature and for seasonal weather forecasts.”
For now, the plummeting sea ice volumes are a startling reminder of just how rapidly the planet is changing, and how dire the consequences of delaying radical cuts in greenhouse gas emissions will be.”
https://www.vox.com/21536859/arctic-sea-ice-2020-climate-change-alaska-polar-bears-charts