Jared Diamond did a very good chapter on the Greenland Colony in his book "Collapse". Were you to read it, and other real histories of the era, you would find that nothing that you have stated is true. At the best of times, that colony was marginal.
And they died out because they refused to recognize that the way they were living was not sustainable. The same lesson that we are currently refusing to learn.
They were living in a marginal area to begin with, where the warming and cooling of temperatures over time made a huge difference, I do agree with that. but, it WAS caused by the natural cycles.
So your point being?
A natural cycle that they did not adjust to doomed them and their children to death.
A manmade climate change that we refuse to recognize or prepare for can do the same for our culture.
Until you can tell me how we have gone from ice age, to global warmimg over, and over, through millions of years. I'm not going to believe that in the last 130 years it has become Man made global warming. Hell, no one can even put a digit on what the correct temperature is suppose to be. So don't try to sell your goods with me.