The problem is that he's really not saying anything of substance. He makes an appeal to rationality and then proceeds on a disorganized discussion that doesn't

The problem is that he's really not saying anything of substance. He makes an appeal to rationality and then proceeds on a disorganized discussion that doesn't come to any useful conclusion. Botkin says "We are told that the melting of the arctic ice will be a disaster." Then he seems to be trying to refute this passage by saying that a warmer climate worked out great for the vikings. He doesn't attempt any sort of analysis of what the real-world effects of change in sea-level would be. Botkin may have something worth saying, but he needs an editor to help him focus in on clearly stating and backing up the points that he wants to make. All I can get from this is that he wants people to stop the panic because, hey, there might be some benefits from a warmer climate.