http://www.bbc.com/news/science-environment-26387276 Thawing the permafrost may release long dormant viruses. They may or may not be human pathogens, but there are also risks from plant and animal pathogens. This really wasn't intended to be a debate, but given global warming is involved, I thought this would be the safest sub-forum just in case. I thought people might be interested. It is after all, a more likely sci-fi scenario than an organism arriving from space. Organisms from space wouldn't have evolved to interact with life on this planet. But thawing a long dormant virus that can adapt to corn or rice or people is a very plausible scenario.