Is this the only time the planets temperature has been on a rise?

The climate is extremely hard to predict. Fluctuations of atmospheric content and global temperature are always variables that are easily manipulated and never stay the same for a long period of time. So is the only time that we know that the temperature has been on the rise? Of course not, the records we have collected over the years date hundreds of thousands of years into the past and show that the earth has gone through many peaks and troughs.

However, recently we can see the change between to different climate periods. Up until 1940 we could see that the earth was on a steady rise in the temperature department. Looking for answers to what caused this rise in global temperature, scientist settled on the thought of increased solar activity and the decrease in volcanic activity. As of recently, both of these factors have reversed completely. Solar activity has been steady recently, and an increase in volcanic action has been noted.

Source: http://www.skepticalscience.com/global-warming-early-20th-century.htm