What causes an Ice age? And when will the next one be?

The next ice age could begin any day.
Next week, next month, next year, it's not a question of if, only when. One day you'll wake up--or you won't wake up, rather--buried beneath nine stories of snow. It's all part of a dependable, predictable cycle, a natural cycle that returns like clockwork every 11,500 years. It has been 11,500 years since the last one.
Source:CLICK HERE

There is a article in the new Discover Magizine that talks about the glaciers melting at such a rapid rate causing a flow of cold fresh water into the gulf stream. That this might cause a ice age within a dacade.