I still think the idea that what we are doing is causing global warming is a bunch of garbage designed to destroy capitalism. The sun causes global warming, period. What were the CO2 emissions coming from that caused the glaciers to recede from Michigan?
Actually, to say that the Sun causes global warming, period, doesn't even characterize the main cause of glacial/interglacial cycles. The main cause of those cycles is Milankovitch forcing, due to variability of the Earth's orbital eccentricity, axial tilt, and axial precesssion. These factors alter the amount of solar insolation the Earth receives (so it's the Earth's fault, not the Sun). Changing solar insolation alters the Earth's radiative balance.
Increasing concentrations of CO2 in the atmosphere in the middle of a stable interglacial period (i.e. now) also alters Earth's radiative balance. The predicted effect of this change is an increase in global temperature.