This is an interesting subject shot through with more BS than a democratic election campaign.
I've got a 7 page series planned for this section. But for the moment, you'll have to be satisfied with this: http://21stcenturysciencetech.com/articles/Ice_Age.html
The very short version is: the "global warming" hysteria is pure, 100%, unadulterated, BS! It's just another way for the "intelligentsia" to get their hands into the pockets working folks, and continue the process of weaning us away from thinking and taking responsibility for ourselves.
The facts: Once every 100,000 years of so, we have notable "global warming" as our climate transitions from 'ice age' to the the inter-glacial period. We are today, depending upon who is counting and from where, about 500 years from the end of the current warm period, or up to about 750 years or more into the start of the next 'ice age'. Global warming nitwits not withstanding...