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.
[plantabillion.org. April 24, 2015 is Arbor Day. Plant a tree and/or join the Arbor Day Foundation. For a membership fee of $10, they will plant ten trees in an endangered forest in your honor.] * * AWESOME.
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."