Reddit reviews Children Of The Earth...Remember

I don't know if you're familiar with the Magic School Bus books (and TV show), but they do a fantastic job of introducing science topics to kids, and climate change is no exception. Definitely check out Magic School Bus and the Climate Challenge. There's a good list of other books with environmental and conservation themes here. A few of my favorites are Earth Dance and The Great Kapok Tree; Children of the Earth, Remember is a bit more intense, written as a letter from Mother Earth; The Earth Book and What Does it Mean to be Green? have concrete ideas for what young kids can do; and in a few years you might consider the chapter book Hoot as a read-aloud (great empowering message about kids saving an endangered species of owls). Also the book Ordinary Mary's Extraordinary Deed isn't about environmental issues per se, but is great for showing the impact a single person can have on the world.

I think it's fine to talk about things like this in an age-appropriate way, with a hopeful, positive, "this is what you can do to help" spin. I wouldn't show her a documentary aimed at adults. You wouldn't show a 5-year-old a documentary that graphically depicted poverty or violence, you would talk to them about how some people are less fortunate and that's why we donate cans to the food bank, or that's why it's important to be kind to each other instead of hitting - things that are actionable for a 5yo. Similarly I think it's important to start the conversation about environmental issues early, but it needs to be done in a way that's encouraging and educational rather than discouraging and hopeless. More than "hardened, determined warriors" I think we need informed, concerned citizens - people who understand the science and are committed to making things better. I don't think it's too early to start instilling those values, and empowering her to be an agent of positive change in the world.