Illustrating the enhanced greenhouse effect

This task is about interpreting a science cartoon about the enhanced greenhouse effect.

Question

greenhouse-effect-cartoon.png
 
These two pictures convey an important idea about the greenhouse effect. 
a)  In this context, "enhanced" means:  

    • to make something better

    •  to increase an effect

    •  to clarify something

    •  to create something new.

Question 2Change answer

b)  What "message" about the greenhouse effect is the artist giving us? 
     Explain this message in a short paragraph.