re: #2, see the huge instability of the permafrost in areas that are currently warming. It's not a good place to settle humans. http://www.news.com.au/technolo

re: #2, see the huge instability of the permafrost in areas that are currently warming. It's not a good place to settle humans. http://www.news.com.au/technology/environment/siberia-crater-gateway-to-the-underworld-melting-permafrost-a-huge-problem-for-the-planet/news-story/4ea355a6cafc70f433b4a4e526c91b0c http://www.news.com.au/technology/environment/siberia-crater...