'Earth: The Biography' shows why volcanoes go boom

'Earth' man: Iain Stewart
EARTH: THE BIOGRAPHY. Sunday at 9 p.m., Nat. Geo.

Volcanoes are loud and hot. Ice is cold. Air is always in motion. Oceans are densely populated.

"Earth: The Biography," a breathy five-hour series that launches Sunday night on National Geographic, is one of those shows that figures we periodically need to be reminded about important stuff we mostly know, but sometimes forget.

It won't remind anyone of a geography class lecture, however, because narrator Iain Stewart speaks as if he is channeling the late Steve Irwin.

His delivery suggests that at least one item in every sentence is utterly amazing, and while there are sentences in which that is true, he doesn't seem to draw distinctions between a mildly interesting factoid and something that shaped life as we know it.

He sometimes seems to be striving for "infotainment," which is a fact of TV life, but doesn't seem essential when you're talking about the basic physical and geological forces of the planet. They're a story that doesn't need a lot of embellishment.

Stewart knows that, of course, and they do form the core of this five-part, three-night production. The material is accurate and informative, with great pictures to lure the casual channel surfer.

Stewart sprinkles the show with small warnings about things human beings are doing to the planet. But against the larger canvas he's painting, they seem curiously minor. No matter how carefully we tend to a piece of land, a volcano can still blast through it and completely rearrange it.

Stewart also emphasizes nature's patience. We get angry about waiting five minutes for a subway train. Nature is willing to spend 450 million years to create a superheated volcanic "plume" that's 100 miles wide, 370 miles deep and only 12 miles under the surface of Iceland.

That's why a country made up mostly of ice has "hot springs" where you can bob around as if it were a bathtub.

Tonight's opening segment focuses on volcanoes, which starting maybe four and a half billion years ago began to shape the Earth as we know it. Today the heat that fuels those volcanoes is trapped under the surface, which is why occasionally we see it burst out through a Mount St. Helens and why eventually somewhere there will be a much bigger blow.

We living creatures have never assembled anything that comes close to the forces of ice or the air, Stewart tacitly reminds us. For starters, we haven't been here long enough, and unless something remarkable happens, we probably won't be.

About the most we can do, Stewart suggests, is figure out how nature works so we can develop a strategy for living with it. We're making a little progress there, sort of. But if the ocean wants to bust a wave or the volcano wants to spit tons of carbon dioxide into the air, there isn't a lot we can do except watch.