Despite the good intentions, Earthships in cold climates can't work because they contradict the laws of physics. I'm not the Mike Reynolds who invented the Earthship, I'm the Mike Reynolds who thinks Earthships in Canada and other cold climates are a bad idea.
How To Build A Wood Stove Greenhouse Heater.Rocket stove heater built into cob furniture/seating that keeps warm in the winter. | Cob house, Earthship home, House design.

Building Earthships is a good way to save money building a home and to reuse a lot of material that would otherwise be bound for the dump in most cases.

These fully sustainable, off-the-grid dwellings can maintain a comfortable interior temperature regardless of the heat or cold outside. Photos: Home sweet earthship.

Such details provide a deeper understanding and appreciation for Earthship Building Techniques For Cold Climates.
Products. Tips & Techniques.Via the Permaculture Research Institute of Australia, I've just come across this great slideshow showing a step-by-step progression through the building of an earthship in Normandy, France.
Climate makes no difference for an Earthship they can be constructed almost anywhere. The firm has plans to build homes in regions from tropical to deep-winter.
The Earthship building design is a trademark of architect Mike Reynolds. These homes can be built from all kinds of scrap materials.They have also been built in hot climates, cold ones, wet, dry, and just about every other place you can imagine.