Permafrost is the layer of permanently frozen earth – over a 1,000 metres thick in some places – that lies just beneath the land surface in Arctic regions. It formed over the past few million years when ice ages predominated.
Permafrost is the layer of permanently frozen earth – over a 1,000 metres thick in some places – that lies just beneath the land surface in Arctic regions. It formed over the past few million years when ice ages predominated.