Parents need to know that this nature/science show's repeated images of dangerous events and the narration's relentless doom and gloom could be upsetting to young kids and tweens. It's true that many of the issues the series covers do have deadly potential, but the show's emphasis on that perspective is disproportionate.
Positive messages:While the show features lots of scientists talking intelligently about each episode's topic, the narration tends to focus on the dangerous and deadly in a very exploitative way (for example, calling volcanoes "mass murderers").
Violence:While there's plenty of devastation to be seen -- villages ravaged by volcano erruptions, etc. -- there are almost no bodies. That said, the narration is relentless, repeating over and over how many people have been killed by the featured events/disasters, etc.