No global warming catastrophe movie is complete without scenes of melting glaciers. And it is true that many (but by no means all) of the world’s large glaciers have retreated over the last century. The implication is that this retreat is due to man.
The reason I titled my climate video "What is Normal?" is because I am facinated with the hubris we have of observing climate for just a few decades, but suddenly declaring we know what is a "normal" or "abnormal" climate. Such may be the case with retreating glaciers.
This is a picture published in Alaska Geographic Magazine, plotting the retreat of the famous glacier at Glacier Bay, Alaska.
As you can see, the vast majority of the retreat occured between 1794 and 1907, before man is generally blamed with substantially affecting the climate with CO2. Yes, we have seen some retreats in the last 50 years, but in this context they look much more like a continuation of a natural trend than any new man-made phenomenon. In fact, to claim that recent retreats are man-made, one would have to argue that the natural forces driving glacier retreats since 1794 would have had to halt around 1950, coincidently exactly when man’s impact began. This kind of coincident occurance isn’t impossible, but certainly fails any Occam’s Razor smell test.