This is a sample lesson plan that could be adapted for any grade level. Not only does it discuss what deforestation is, but also goes into the causes and consequences of it around the world. It also mentions ways to "lessen the amount of deforestation."
INFOGRAPHIC: What is driving deforestation and what can you do about it?
Beautiful digital art you could display in your classroom to facilitate discussion about global warming. You could present one of images and ask the students what they think it's trying to convey, no text is needed to spark discussion. Great way to get students interested and engaged in the topic.