This is EXCELLENT & worth reading in its entirety. It explains with the help of illustrations what global warming is, the consequences for our planet & its ecosystems & the potential threat to the human population. Most important, it says how each & everyone of us can help slow it down.
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.
Save the Earth by Patrick Carroll. "Over-consumption, global warming and a lack of sustainability are slowly degrading of the ability of the Earth to support us. This poster has a simple message; the world needs to react before it is too late."