The remaining 20% can be attributed to long-term ice thinning caused by global warming.About the Arctic:

The Arctic is a polar region located in the far north of the Earth.

The Arctic Ocean and adjacent seas, as well as parts of Alaska (United States), Greenland (Denmark), Canada, Finland, Iceland, Norway, Russia, and Sweden, comprise the Arctic.

Land in the Arctic region experiences seasonal variations in snow and ice cover.

India has been an observer in the Arctic Council since 2013, which is the primary inter-governmental forum for cooperation on Arctic environmental and development issues.