The earth is a changing, but it has changed many times before. The thesis that it is man's fault cannot be proved. The colorado river dried up long before fossil fuels
In some places, glaciers appear to be retreating (they vary year to year according to the average snowfall) and in othr places they are growing tremendously. Greenland for example has glaciers that have grown over 200 feet thicker than from 1945, and is overall more snow covered than at the beginning of the last century.