This article puts present day discussions of climate change in context.  It points out that science has struggled to explain fully why an ice age occurs every 100,000 years. As researchers now demonstrate based on a computer simulation, not only do variations in insolation play a key role, but also the mutual influence of glaciated continents and climate.  The model the researchers created explains why the periodic ice ages begin slowly and end abruptly.

Science Daily, August 7, 2013

Carbon Emissions and Temperature