Last summer, a photo of fast-melting sea ice on Greenland went viral.
Danish scientists were overwhelmed by the heat this summer and had to make their planned trip on sea ice with a solid layer of water. Melting sea ice is not in itself fearful. The melting season is always from June to August and is an annual phenomenon. In these months the temperatures rise above zero and the ice begins to melt. Not only the ice in the fjords is melting, as in the iconic photo, but also the ice from the glaciers in Greenland. And in the winter the ice grows again.
Below the layer that goes with the seasons is a layer that is called perennial ice. That is the sea ice that stays on for a long time and can have a thickness of up to 10 meters. NASA research now shows that the thickness and size of that permanent sea ice sheet is now much less in 2019 than more than 30 years ago.
The melting of sea ice has no influence on the height of the sea level, since it floats on the water and moves just as much water as it weighs itself. Yet it is important for the climate. Less ice reflects less sunlight, causing it to heat up more. That is one of the reasons why global warming in the Arctic is greater than elsewhere.
In 2007, the IPCC expected that there would be an ice-free North Pole for the first time in the summer around 2100. More recent research indicates that there is a reasonable chance that the North Pole will become ice-free in the summer minimum before the middle of this century. This means that no thick, multi-year ice is left at the North Pole, but that all the ice that is still present remains from the same winter.
In the NASA animation below you can see in a timelapse how the multi-year ice is subject to change.