I'll have to check it out later
but it reminds me of back in the 1970's, when Jimmy Carter whined about the energy crisis, and there was a flourish of earth protected underground homes: The locals in South Dakota just laughed and said: Well that's how our ancestors lived, so what's the big deal. Like Iceland, there were few decent trees on the South Dakota praries....
Wikipedia on sod houses has lots of links
|wikipedia commons: Sod house on American prarie|
Which makes me wonder: Where did their ancestors learn to use the thick turf to make a house?
Many early viking houses were partly underground too. Was this because of the lack of wood in Iceland, or was this used in Norway? In Kristin Lavransdattir, the houses are all made of wood. But what about the poor? Would sod be warmer?
Icelandic turf home article.
In Iceland, the cows were often kept in the house, which not only kept them safe but their body heat helped keep the house warm. I read somewhere that due to lack of exercize they had to carry them out in the spring, but don't quote me here.
as for Hobbit Holes: Note that they would be in hills, making them warm and less damp then these houses.
Something to look up later when I am bored