JOAN CARTAN-HANSEN, HOST: Glaciers cover only about 10 percent of the Earth's surface and yet play a major role in the health of our planet.

Find out more about glaciers.

(SCIENCE TREK MUSIC) KID ONE: What are we doing here?

KID TWO: Looking for glaciers.

KID ONE: What's a glacier?

CARTAN-HANSEN: What's a glacier?

Glaciers are really, really, large masses of snow the packs down on itself over really long periods of time.

Eventually all that snow gets so tightly packed down that it turns into ice.

KID ONE: what?

CARTAN-HANSEN: Okay, let's have a glacier scientist explain it.

ELLEN ENDERLIN, ASST.

PROG.

OF GEOSCIENCE, BOISE STATE: So, you can think of this if you live in a place that's snowy, where if you make a really, really, hard snowball, It almost feels like ice if you get hit with one of those, or if you hit someone else, or if you're in a place where people tend to not shovel their sidewalks in the winter, that snow builds up over time and then people step on it.

That's pressing it down eventually.

It feels a lot like ice.

It gets really, really, slippery.

It's that same process going on for glaciers.

It's that snow building up over time, but it's just the weight of the snow is pressing it down and it causes it to turn to ice.

And then eventually it gets so big that gravity acts on it and it causes it to flow downhill.

And then that's when you have a glacier.

CARTAN-HANSEN: Glaciers are found near the north and south poles and in mountain ranges.

There're two basic types of glaciers.

Continental glaciers or ice sheets are wide, thick sheets of ice covering most of Antarctica and Greenland.

These ice sheets can more than two miles or three kilometers thick.

They build up in the center and slope downwards toward the edge and cover the land completely.

Alpine glaciers are formed high in the mountainsides and slowly move downward.

They come in different shapes.

Valley glaciers are long and narrow.

And piedmont glaciers are formed at the base of a mountain.

They spread out onto flat land and make a round, lump shape.

Glaciers of all kinds share three characteristics: They form on land.

They are made of ice, And they move.

KID TWO: They move?

KID ONE: That's right.

KID TWO: How do they move.

KID ONE: Gravity.

KID TWO: Gravity?

CARTAN-HANSEN: Gravity.

The same force that pulls a skateboarder down a slope, is what makes glaciers move.

In fact, glaciers are the largest moving objects on earth.

Think of them as rivers of ice.

Heat from the Earth's surface and friction cause the bottom of a glacier to slightly melt, and gravity pulls them downward.

And moving glaciers scrape away the landscape, leaving behind mountains and valleys.

KID TWO: Mountains and valleys?

How fast do glaciers move?

CARTAN-HANSEN: Glaciers move at different speeds.

Most move at less than an inch each day.

Others go through fast moving periods called surges.

These can move hundreds of feet a day.

KID TWO: If they move so slowly, how did glaciers create mountains and valleys?

KID ONE: Because they did it over vast periods of time.

The glaciers we have today are leftovers from the Ice Age.

KID TWO: Oh, okay.

But why are we still looking for them today?

KID ONE: Because they are disappearing.

KID TWO: Disappearing?

Why?

CARTAN-HANSEN: Because of climate change.

As the earth's average temperature rises, glaciers melt faster.

ENDERLIN: Glaciers are not doing well worldwide.

we see that all around the globe, glaciers are getting smaller.

CARTAN-HANSEN: And this isn't a problem just at the north and south pole.

Glacier store about 69 percent of the world's fresh water.

About two billion people across the world depend upon mountain glaciers and snowpack for their drinking water and more.

ENDERLIN: In the Andes, they really rely on them for hydroelectric power, for irrigation, for all sorts of things for drinking water, they're seeing a decrease in their water.

And other places where you know more on that, wow, we're getting an increase in water.

And then you have these hazards associated with flooding.

associated with flooding.

associated with flooding.

CARTAN-HANSEN: And there's an even bigger reason to be concerned about glacier melt.

ENDERLIN: They're also really important for, um, controlling things like our world's climate, which often you don't really think about the fact that our climate is also sensitive to what is going on the earth's surface.

As they get smaller, they reflect less energy from the sun.

You know, snow is really bright white.

You go outside on a sunny day after it snowed.

And if the cover your eyes, they are reflecting the sun's energy as they get smaller.

We expose more land and water to the sun's ray and that's a darker surface that absorbs more of the sun's energy.

So in fact, when we lose our glaciers, we absorb more of the sun's energy and then that causes the atmosphere to warm even more.

And also as we pump out more water into the oceans, that can influence our ocean circulation as well, which also controls climate.

KID TWO: So what can we do?

KID ONE: Yah, what can we do?

ENDERLIN: we can reduce our carbon footprint, meaning how much fossil fuels basically we, we burn, how much plastic we use that's also made from oil.

So, we can reduce what we're using, how we're making use of the earth three sources.

And that will actually help us with glaciers.

There'll still be a time that will get smaller, but it doesn't mean that we have to have all of the glaciers go away.

CARTAN-HANSEN: You can also learn more about glaciers and how they impact our world.

KID TWO: Good idea.

Let's start climbing KID ONE: Umm, I think we can study glaciers from here.

KID TWO: Better idea.

Hand over those binoculars.

I want to see.

CARTAN-HANSEN: If you want to learn more about glaciers, check out the Science Trek website.

You'll find it at ScienceTrek.org.

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