This is a great podcast by Dr. Aparna Boles, a pediatrician who is chair of the American Academy of Pediatrics Committee on Environmental Health. She has good advice: “Tell your children the truth, but frame it with hope,” and “We have the ability to act on climate change right now.”
It is 18 minutes long, and well worth listening to.
http://radiomd.com/show/healthy-children/item/41379-how-to-talk-to-your-kids-about-climate-change