weather

• they use triple - glazed windows in the extreme cold
• heat from houses created an 'urban heat island effect' and made the melting of the active layer worse, particularly below houses. as the ice melted, the houses subsided
• in the 1880s, millions of kilometres of permafrost were damaged from heat from houses
• today, buildings are building on stilts or raised piles to prevent melting, they go deep into the ground, below the active layer of melting and are several metres above the surface
• roads are now built on gravel pads 1-2 metres deep to prevent artificial melting of the active layer
• airport runways are also painted white to reflect the sun and prevent them from warming too much on the rare sunny days