TV

High-definition was made for such specials as National Geographic Channel's Earth: The Biography, a five-hour, three-night homage to the world that surrounds us. What better way to show off that 50-inch screen than with sweeping vistas of parched deserts, lightning arcing across the sky and steaming volcanoes?

But this sprawling ode to our planet, beginning Sunday and running through Tuesday — Sunday and Monday at 8 p.m., Tuesday at 7 p.m. on the digital cable channel — isn't just about pretty pictures.

It tells the tale of Earth through its natural wonders and how they might be in danger. Sunday's two parts are devoted to volcanoes and ice, Monday's focus on the atmosphere and the oceans, while Tuesday's finale, Rare Planet, pulls together all the strands to show why Earth may be uniquely endowed with complex life despite there being potentially millions of planets in the universe.

Hosted by University of Glasgow earth scientist Iain Stewart and filmed on all seven continents, Earth: The Biography is nothing if not ambitious and it's all in service of a larger point: The Earth, which has gone through at least two cataclysms (including the one that led to the extinction of dinosaurs), is not in stasis.

There are no guarantees that humanity will be around to see how the planet's future plays out. To paraphrase the title of the classic George R. Stewart apocalyptic novel, Earth abides but man might not.

So it's all the more important that we be aware of how the planet works and how our behavior affects that, for good or ill. But even a viewer who doesn't want to consider such implications can still find value in Earth: The Biography, Iain Stewart puts on a very dramatic and impressive show as he takes us through a variety of vistas.