Earth is a big change of pace from the comedies and action movies I usually see. It's a documentary staring the natural beauties of our planet. It does feature amazing landscapes from around the world and is a joy to just watch. But, it does come with very good narration. The "American" version I saw is with James Earl Jones and is well done. The English one is with Patrick Stewart. I wonder if both will be available on the DVD.
Besides the plants, trees, water, ice and snow, there are lots of animals too. We follow the migration of a few families in particular, as well as many other random ones. Nature is a hard world to live in and we do get a sense of this, although it never gets bloody. Scenes of predators catching their prey usually cuts before it gets too graphic. There were lots of kids in the theatre and I don't think any of them were traumatized... I didn't notice any parent having to take their kid's out of the room, at the very least.
There is a message in the movie, regarding global warming, but it's rather subtle. It doesn't try to explain why it's happening or what should be done about it. They just state the fact that it's a big problem for bears and other animals that the ice at the poles is thinning, there is less of it surface-wise and it's happening for longer period of times.
The planet is changing, but life goes on. I went to see this movie for it's beautiful looks and I did get that. And seeing it on a big screen does amplify this, so I suggest you go see it in this format as well.