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CNN Live Event/Special

Encore Presentation - Planet In Peril Part II

Aired December 25, 2007 - 21:00   ET

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

(BEGIN VIDEOTAPE)
ANDERSON COOPER, HOST (voice-over): For every action, there is an equal and opposite reaction. It's one of the fundamental laws of physics, of nature. Nothing occurs in a vacuum in the natural world. There are ripple effects and that is putting our planet in peril.

This journey around the globe is an investigation into the reasons our planet is changing. It's about the front lines, the places where threats aren't just forecasts of the future, but are happening now.

Where forests are lost.

UNIDENTIFIED MALE: We're destroying nature's natural regulators.

COOPER: Where islands are discovered.

UNIDENTIFIED MALE: This island exists because of global warming.

COOPER: Where water is poisoned.

DR. SANJAY GUPTA, CNN CORRESPONDENT: A lot of people live around here and are dependent on this water.

COOPER: Where endangered animals are bought and sold and killed.

UNIDENTIFIED MALE: There's a lot of animals right here that range the gamut of critical status.

COOPER: Where people are dying.

GUPTA: We're hearing people are getting cancer from drinking water.

COOPER: This is a planet under assault. This is a planet in peril.

(on camera): Tonight, we begin a place that's warming faster than just about any other place on Earth -- Greenland's ice sheet. Right now in Greenland, it is eight degrees warmer than it was just about 10 years ago. Eight degrees. Scientists say that is happening because of what we're putting into the air -- tons and tons of carbon dioxide.

(voice-over): The vast ice sheet of Greenland -- 1,500 miles long and more than a mile deep, the world's largest island. Eighty percent of it covered by ice. It's springtime here, though nothing is green. This time of year the sun never sets -- just dips down to rest on the horizon. We're almost at the top of the world. But to really see what's happening here, you need to get on the ground. The ice is melting fast and this island is warming.

JEFF CORWIN, "ANIMAL PLANET": It's like nothing my eyes have ever experienced.

COOPER (on camera): It's all so surreal, I mean, as you look out at the horizon.

(voice-over): Biologist Jeff Corwin and I have come here to learn why and see what impact Greenland's melting ice sheets could have on all of us in the decades ahead.

DR. KONRAD STEFFEN, UNIVERSITY OF COLORADO: We have never seen a temperature rise in Greenland that drastic over a short period. It's only about eight years.

COOPER (on camera): So how far have we come?

STEFFEN: We actually drove 11 miles.

COOPER (voice-over): Dr. Konrad Steffen of the University of Colorado has spent 17 seasons here, 300 miles north of the Arctic Circle.

(on camera): What are these rotating things?

STEFFEN: We have several sensors at different levels. These small planes, they measure the wind velocity.

COOPER (voice-over): He records the changing ice sheet through a network of monitoring and GPS stations. He's taking us to see and actually climb into a part of the landscape that's giving scientists important clues about why the ice is melting so fast.

The Earth's climate has changed much during the planet's history. There have been ice ages and long periods of warmer temperatures. But scientists say our burning of fossil fuels like coal and oil has caused a greater concentration of heat trapping greenhouse gases in our atmosphere. This buildup of gases prevents heat from escaping to space, acting like the panels of a greenhouse -- warming the entire planet. Arctic temperatures are rising faster than anywhere else on Earth.

Why?

As the atmosphere warms, the ice here melts and breaks apart, exposing water. That water absorbs the sun's heat and causes more ice to melt. Scientists call it a positive feedback loop, and it's causing Greenland's ice to disappear. Last year, satellite data collected by NASA scientists revealed Greenland is losing 100 billion tons of ice each year. Ice does accumulate in the interior, but more ice is breaking off and melting at the edges.

It's that imbalance which concerns scientists the most. If the entire ice sheet dissolved, sea levels would rise by 23 feet -- spurning a global catastrophe that would flood coastal cities and displace tens of millions of people. Scientists don't think the entire ice sheet can melt any time soon, but every inch of sea level rise counts. Millions live near coastlines less than three feet above sea level.

(on camera): You've been coming here since 1990?

STEFFEN: Well, we actually started in 1990. We came here not with the idea to monitor the abrupt change we currently observe. The first two or three years were actually colder than normal. But then '94, '95, it started to warm steadily. And since then, we actually have a temperature increase during the winter months of about four-and-a-half degrees Centigrade, which is a very large increase.

COOPER: Four-and-a-half degrees, that's enormous.

STEFFEN: That's one of the largest temperature increases we have on Earth.

COOPER (voice-over): Four-and-a-half degrees Celsius is eight degrees Fahrenheit. And here on the ice sheet, you can see the impact that temperature increase is having. It's creating rivers of melt water that carve deep holes in the ice called a moulins (ph).

(on camera): So this is a moola (ph)?

STEFFEN: Yes, this is a moulin. You can see the water channel coming over it now. Well, let's explore it further.

COOPER (voice-over): As more ice melts, more moulins appear. We gear up to rappel ourselves down inside. Hurling yourself backwards over a 1,500 foot cliff does take some practice.

CORWIN: It's easy. Just let yourself slide down, Anderson.

COOPER (on camera): Lean back.

CORWIN: Lean back and steer. And remember, if you want to brake, pull the rope up toward you.

COOPER: Climb back.

What the (EXPLETIVE DELETED).

CORWIN: You've got to lean back. Step up. Step up. Step up. Excellent. Yes!

COOPER: I've (INAUDIBLE).

CORWIN: So now you feed the rope and it will just slide down like this.

COOPER: That was far more unpleasant than it needed to be.

So right now, obviously, there's snow here, but this could go much deeper.

STEFFEN: Yes. Usually these channels are up to 20, 30, 40 feet deep.

COOPER: So in the summer months ahead, as the temperature increases, water will actually start flowing through here?

STEFFEN: Oh, yes. Definitely. The water is so fast and has energy that actually carves into the ice before it drops into the moulin.

COOPER (voice-over): Last year, Konnie and his team actually lowered a camera inside a moulin, capturing the first video from deep inside this icy tunnel.

(on camera): And what is the big picture?

What's the significance of a moulin?

STEFFEN: It actually is a conduit through the ice -- the ice sheet. And the water can reach the bottom of the ice. So once this moulin fills with water -- and water is heavier than ice -- it's possible that to lift up the ice. And then it's a (INAUDIBLE) beneath the ice. And that's what we see the ice moves faster.

CORWIN: So, basically, it's providing this layer of viscosity to the ice to slide on.

COOPER: So, because of the research you've been doing here, what is it that alarms you in terms of climate change?

STEFFEN: First of all, it got much warmer than we expected. So the melt season got much larger. If you look at the latest reports put together by all scientists that discuss the climate change, they estimate the sea level rise by 2100 to be about 50 centimeters -- one a-and-a-half foot. If you take that number -- this is only based on melt. It's not based on the fast flow that generates additional icebergs. By 2100, we will be more likely one meter -- three feet -- instead of one-and-a-half feet.

COOPER: If the sea levels, by the models that we have now, are going to rise three feet in the next hundred years, can that be reversed still?

Can that be lessened?

STEFFEN: Even if you reduce CO2 output at the current level and leave it level, the climate will continue to warm. So even by stopping the increase of CO2 today, we will have a warming. We will have a sea level increase.

COOPER: Climate change isn't just having an impact here in the interior of Greenland. You also see dramatic changes in the overall geography of the island, particularly on the coastal areas. We're going to travel to the east coast of Greenland, where a new island emerged because of the retreat of ice.

UNIDENTIFIED MALE: That's it, right there.

(END VIDEOTAPE)

(COMMERCIAL BREAK)

COOPER: I'm Anderson Cooper, Rancho Bernardo, California.

"Planet In Peril" continues in a moment.

Here's the latest on tonight's breaking news -- the wildfires. They are still burning and still dangerous, but they are moving more slowly. The dry Santa Ana winds have let up.

In all, there are 15 active fires tonight. Some evacuees here are getting their first look at the damage. They have a tentative price tag. It is staggering -- at least $1 billion in San Diego County alone. Northeast of here, in the mountains around Lake Arrowhead, thick smoke forcing a three hour stop for water aerial drops. They have resumed now. About 500 homes in that area have burned.

Authorities say the Santiago Fire near Los Angeles had three points of origin. Arson investigators are on the case and we expect a $50,000 award for information to be announced soon.

President Bush today declared a major disaster area here in California. He's going to visit the state tomorrow.

I'm Anderson Cooper.

"Planet In Peril" continues after this break.

Another update in 15 minutes.

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

COOPER (voice-over): From Greenland's interior ice sheet, we travel to its east coast with Dennis Schmidt.

(on camera): Do you expect to find other islands that were previously thought to be connected to the inland?

DENNIS SCHMIDT: Yes. There will be others. In fact, we know where they are. We're looking for...

COOPER (voice-over): Schmidt is a modern-day explorer. San Francisco is his home base, but Greenland is more like home.

SCHMIDT: This is a peninsula -- it's an isthmus connected to the mainland because of an ice shell.

COOPER: He's been coming here for more than 40 years. His explorations have led to discovery.

UNIDENTIFIED MALE: Yes, OK. We're flying right over it now. We're just on top of it.

COOPER: I joined him to see his latest -- one of the starkest examples of climate change. It's not easy to land on a glacier, especially one jutting out from a steep mountain. Our pilots make several passes scouting for a safe place. The co-pilot jumps out to test the snow pack. Finally, we put down. We are the first people to ever visit here.

SCHMIDT: No one has ever been here before. We're the first people ever to walk here.

COOPER (on camera): No one has ever been here?

Really?

SCHMIDT: No, we're the first to ever walk here.

COOPER (voice-over): We're here to see something extraordinary -- Greenland's retreating ice has revealed a new island.

(on camera): In 2005, you came here. You were on a ship...

SCHMIDT: Yes.

COOPER: When did you realize, wait a minute, this is an island, this is not part of the mainland?

SCHMIDT: Yes. I sailed into the peninsula. As we sailed into the base of it and we kept finding open water, I became disoriented. That was the beginning of the movement discovery, where I realized something was wrong. Either I was in a different place or the place where I was had completely changed. And I pointed to the area of open water at the edge of the face of the glacier and I said that's the world's newest island.

COOPER (voice-over): The world's newest island, discovered because of the world's warming temperature.

(on camera): So is this island an example of global warming?

SCHMIDT: This island exists because of global warming. This is a peninsula that became an island because the ice fields that connected it to the mainland of Greenland melted and structurally destabilized and broke away. So without the climate change, this would still be a peninsula.

COOPER: You have to be very careful when you're walking on a sheet of ice or a glacier in Greenland because there can be hidden crevices that open up. You could fall right through, and that will be the end of you. The thickness of the ice in Greenland has been changing over the last few decades. It's of great concern to scientists who are studying it. They found that in some spots, ice thickness has diminished by as much as 40 percent in the last 40 years.

SCHMIDT: That's what you want to look at now. We want to study this.

COOPER (voice-over): When you discover an island here, pending approval, you get to name it. Dennis chose the name Warming Island.

(on camera): That's a glacier over there and these two glaciers used to be connected by an ice shell?

SCHMIDT: They were continuous, yes.

COOPER (voice-over): Even the map of Greenland is changing. After two days exploring with Dennis Schmidt, we head back to the interior and Dr. Konrad Steffen.

STEFFEN: Hey.

Hi, Anderson.

COOPER (on camera): Does it surprise you that new islands are cropping up in Greenland?

STEFFEN: No, I would not be surprised because we know the ice is retreating.

COOPER (voice-over): Dr. Steffen and his team live in a research station called Swiss Camp. They spend one month every year here, living under extremely difficult circumstances. You have to see it to believe it.

(on camera): So this is where you sleep?

STEFFEN: First, we slept in the station at the beginning.

COOPER: Right.

STEFFEN: But during the cold years, we had some water that froze in the middle tent, which was our sleep tent, which was not very comfortable. So we decided we would go out and put our tents outside.

COOPER (voice-over): In case you're wondering, there is a bathroom. Out here it's an igloo. They call it the shigloo. The cold hasn't snapped their sense of humor.

(on camera): What are these three -- these are tents?

STEFFEN: Yes. This is actually Swiss Camp. This is our office where we have the electronics and computers. We also have a refrigerator. We actually stand in our refrigerator.

COOPER: Oh, nice.

This is your refrigerator?

STEFFEN: Yes.

COOPER: Really?

STEFFEN: But it's filled with fish and some steaks.

COOPER: That sounds good.

So we go down a ladder here?

STEFFEN: Yes.

COOPER: All right.

STEFFEN: Be careful. It is rather steep.

STEFFEN: Hi, Terrie.

UNIDENTIFIED MALE: How are you doing, Konnie?

STEFFEN: Good.

Do you have some coffee?

UNIDENTIFIED MALE: No. It's not ready.

COOPER (voice-over): The makeshift kitchen where the dinner table doubles as a work space. Primitive, but they figured out how to keep the bread maker working.

STEFFEN: We have fresh bread every day. Watch your head here. Then we can go over to the work tent. This is our work center, as we call it, the computing room.

COOPER (voice-over): In this small, cold space, Dr. Steffen and other scientists analyze the data they gather on the ice sheet. A stark finding that for Dr. Steffen raises a very basic question.

STEFFEN: The question is, how can we actually change it for the future?

We should not just think for ourselves. We should think for the next two, three generations.

COOPER (on camera): As Dr. Steffen pointed out, climate change is something that's going to be affecting future generations. But it's also something that's having a major impact on people and animals right now.

Jeff Corwin's gone to track North America's largest carnivore, the polar bear -- to find out what some scientists believe the polar bear's very existence is under threat.

CORWIN (voice-over): Searching for polar bears in Northeastern Alaska isn't like looking for a needle in a haystack, it's like looking for a haystack-colored needle in a haystack.

(on camera) We have incredible terrain of ice that seems to almost go on forever. Somewhere on this ice, on this white-reflected snow and ice, is a white creature that we need to catch up with. (voice-over) Steve Amstrup, a wildlife biologist with the U.S. Geological Survey, has been doing this for 26 years, trying to learn all he can about what polar bears can tell us about global warming.

STEVE AMSTRUP, U.S. GEOLOGICAL SURVEY: There's a nice lead here that we might be able to pick up footprints on.

CORWIN: His eyes are keenly trained to find what seems impossible.

AMSTRUP: OK, you see tracks going across that hill (INAUDIBLE)?

CORWIN (on camera): Oh, my goodness, look at that.

UNIDENTIFIED MALE: Yes.

UNIDENTIFIED MALE: Yes, really.

UNIDENTIFIED MALE: There's one big set of tracks and two smaller sets.

UNIDENTIFIED MALE: We've got a family group.

UNIDENTIFIED MALE: Yes.

CORWIN (voice-over) However, finding the tracks is only the beginning.

AMSTRUP: Boy, they did a 180-degree turn here.

UNIDENTIFIED MALE: She's now at 12 o'clock, doc, right off the nose.

CORWIN: Our helicopter hugs the ground as we trace the footprints through the snowy expanse over the rubbled ice, until finally we spot them.

UNIDENTIFIED MALE: Hey, I see the tracks are going along there. That's a long...

UNIDENTIFIED MALE: And there's a bear right there.

UNIDENTIFIED MALE: Oh, look at that!

UNIDENTIFIED MALE: This is what it's all about right here. We have this sow and she's got some cubs alongside. And now we're going to move in. And you're about to see something absolutely incredible.

UNIDENTIFIED MALE: Boy. Good deal. Yes, straight across. OK. It looks good. We're right on them.

UNIDENTIFIED MALE: We're right on them.

CORWIN (voice-over): Amstrup loads the tranquilizer dart into the gun as we circle low over the mother bear to make sure we don't scare her away from her cubs. Then we lift up and she takes off, racing across the ice. Our helicopter lowers down within feet of her. And Amstrup, hanging from the side of his window, aims and takes his shot.

(END VIDEOTAPE)

(COMMERCIAL BREAK)

COOPER: "Planet In Peril" continues in a moment.

I'm Anderson Cooper in Rancho Bernardo, California.

Here's the latest on tonight's breaking news -- the wildfires.

The Associated Press reports California has maxed out its firefighting resources and is asking the federal government for help. The A.P. says FEMA -- the Federal Emergency Management Agency -- will send 950 firefighters from the U.S. Forest Service into California over the next few days.

There are at least 15 active fires tonight. A little bit ago in San Diego County, about 200 more people were ordered out of their homes. Statewide, nearly one million people have had to flee.

San Diego County came within minutes of suffering a massive power outage this afternoon. Crews managed to clean ash and fire retardant off a line strung across 70 towers and restore power just before the only other major power link to San Diego went offline.

CNN's Ted Rowlands is north of here in the San Bernardino Mountains, near Lake Arrowhead.

What's the situation there -- Ted?

TED ROWLANDS, CNN CORRESPONDENT: Well, Anderson, the battle continues here tonight. They are flying helicopter and planes tonight into the night, trying to get a handle on this fire. We're in the wake of the fire and you can see the devastate it's left behind. Five hundred homes lost here in Lake Arrowhead. Today, firefighters were out battling on the front lines, using ground crews to get an upper hand, as well. Still, 12,000 people evacuated, waiting to find out the fate of their homes, hoping for the best. But many of them will come back, unfortunately, to this -- Anderson.

COOPER: Ted, we'll check in with you at the 11:00 East Coast time, with an hour long look at what has been happening here.

I'm Anderson Cooper.

"Planet In Peril" continues after this break.

Another update in 15 minutes.

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

CORWIN (voice-over): We are on the heels of a mother polar bear and her two cubs. U.S. Geological Survey scientist Steve Amstrup loads his tranquilizer gun. Our helicopter lowers just over the running sow. Amstrup aims and then fires the dart.

UNIDENTIFIED MALE: Did you get it?

AMSTRUP: The top of the shoulder. The top of the shoulder. OK, now let's get the bears back together.

UNIDENTIFIED MALE: So here's the plan. Steve got (INAUDIBLE) shot, he landed that anesthetic dart right in the shoulder about a minute ago. We need to give us some time to drop (INAUDIBLE) rather quickly. Of course, we don't want mom and the cubs to separate. So once (INAUDIBLE) we'll get down and we'll actually physically capture these cubs, anesthetize them and gather data.

CORWIN: That data is part of Amstrup's annual field study. He's exploring how a warming planet is impacting the polar bear. And what he's discovered is startling. Armed with a pistol just in case, Amstrup and I move in to secure the cubs.

UNIDENTIFIED MALE: Put the noose there. I will grab it. OK.

CORWIN: With the bears safely sedated, Amstrup gets to work.

UNIDENTIFIED MALE: The female cub. Polar bears are probably the most important symbol of the Arctic from the standpoint of a measure of the health of the Arctic ecosystem because they are entirely dependent on the surface of the sea ice on catching all of their food and the food that they eat, the seals and other marine mammals, are entirely dependent on the ecosystem below them.

CORWIN: So as the apex or top predator in the ecosystem, polar bears sort of integrate. Everything that's going on in the ecosystem underneath them, 56 even.

Amstrup has been studying the polar bear for the past three decades.

UNIDENTIFIED MALE: 370.

CORWIN: His data indicates an animal that's changing along with the habitat around it.

UNIDENTIFIED MALE: We are starting to see some changes that may result in future concerns for this population. We have seen declines in the survival of cubs and we have seen adult males and cubs a little bit smaller in recent years than they used to be. And those are things that would be consistent with the population that might be under nutritional stress.

CORWIN: Under nutritional stress because it's simply getting harder for bears to eat. It's an impressive opening in the ice here. This is a lead. And of course as you can see, of course, we are not alone.

A polar bear's primary source of prey are seals. They have the most success hunting seals in a 20 to 50-mile gap of water between coastland and ice. The water is more shallow there and the seals are more plentiful. The problem is, though, just like in Greenland, that ice is melting.

UNIDENTIFIED MALE: When the ice melts in the summer, it used to be that it only withdrew from the Alaska coast a little ways. Maybe 10, 15 miles, sometimes a little farther than that. In recent years, we had a gap of sometimes as much as 200 miles north of the Alaska coast.

CORWIN: As a result, biologists are now witnessing some very strange bear behavior. Some of these animals are actually drowning, trying to swim these new open waters. Now, remember, these are marine mammals, so they are not supposed to drown. There are even cases of polar bears cannibalizing each other when the food runs short.

UNIDENTIFIED MALE: Ultimately, they are all dependent on the sea ice. And if the sea ice continues to decline as it has, it's going to affect polar bears.

CORWIN: The sea ice is melting, melting faster than anyone expected. University of Colorado researchers say that in 2007, the Arctic Ocean lost one million square miles of sea ice. That's roughly six times the size of the state of California.

It is a record rate of decline. Sea ice loss has now surpassed predictions for the year 2050. If the melt continues, Amstrup now thinks two-third of the world's polar bears will be gone in 50 years. It's those types of numbers that have led to an unprecedented move. The Bush administration is proposing adding the polar bear to the endangered species list.

It's a global population of polar bears is somewhere between 20, 25,000 animals, why are we today trying to enlist them as an endangered species?

UNIDENTIFIED MALE: The purpose of the proposal that the Fish and Wildlife Service has is not to lift bears because of their present status, because of their present population, but because of their anticipated future status if the sea ice continues to change the way climate models project that it is likely to change.

CORWIN: It would be the first time an animal has been protected because of global warming. It might be the only way to save an animal that, along with its habitat, could simply disappear.

To know that this charismatic, incredible life form could very well become extinct because its habitat is warming up and the ice it needs to survive is disappearing is really most profound. The thing is, we've also learned that climate change is impacting total environments as well as the ice on top of Greenland is very quickly melting way. But above and beyond that, beyond the environment, beyond the impact on wildlife, human beings can be negatively impacted from climate change.

To truly understand that, we are now going to travel with Dr. Sanjay Gupta, as he experiences how climate change is impacting people today in the South Pacific. DR. SANJAY GUPTA, CNN CHIEF MEDICAL CORRESPONDENT: We have been trying to get here for a few days now. It actually took five flights leaving from southern China. They say that the water is going to cover this entire island within a few years. What's going to happen to you?

(COMMERCIAL BREAK)

GUPTA: Flying over the Solomon Sea in the South Pacific, the ocean and the sky melt together in a blue/green haze. We are 60 miles from any land, only open waters in every direction.

On the horizon, a small cluster of islands rise up from the sea, a long coral reef wrapping around them. These are the Carteret Islands of Papa New Guinea, one of the most populated places on earth.

We have been trying to get here for a few days now. It actually took five flights leaving from southern China in a helicopter ride, which you just saw.

We have come here to meet the people of Carteret. The reason that we're here is because we hear that this island is sinking. And it's unclear exactly why. Some people say it's climate change. Some people say it's damage to the coral. Some say it's just sinking naturally because it was built on a volcano.

Over the next few days, we're going to figure out why and report that back to you.

The five islands that make up the Carterets are just five feet above sea level at their highest point. The shoreline is steadily receding. Trees that once stood on the beach are now submerged.

If the islands were uninhabited, it would simply be another mystery in the natural world. Instead, tragically, 2,000 people live here, and they are literally being washed away.

This was their garden. The rising seas have washed it out. It's now a mosquito-infested swamp. The swarms have brought with them malaria. It's now the number one killer here. Do you feel like the people here have been forgotten?

UNIDENTIFIED FEMALE: They have been, definitely.

GUPTA: Rose has lived on the island with her family for 12 years. She says life here used to be good. Now unable to grow their own food, they are dependent on supplies from the government of Papa New Guinea that come twice a year by vote from another island 60 miles away, just twice a year.

UNIDENTIFIED FEMALE: The supply that we have from the government, which is how many bails of rice, it's already finished. And we are living on coconuts. Plus if we have fish from the sea, then we have fish. If we don't, we can live one day without food or two days without food.

GUPTA: That sounds pretty scary. It sounds like people are going to go very hungry, if not starve.

UNIDENTIFIED FEMALE: Yeah, I think so.

GUPTA: It looks like this upsets you?

UNIDENTIFIED FEMALE: It does, it does. It is even very hard.

GUPTA: The people of the Carterets call themselves some of the world's first climb change refugees. What's happening here is a sobering glimpse into what scientist says the future will look like even if modest sea level rise predictions prove true.

Tens of millions of people will have to be relocated. That's exactly what's happening to the people of the Carterets. They are moving to yet another island.

But many don't want to go, and it's easy to see why. This island is a dangerous place. It suffered through a ten-year bloody civil war during the 1990s. Schools were closed for a decade. Thousands were killed. Crime and unemployment are high. The unrest and scars, still visible today.

So for now, the people of the Carterets left to wait and fight against the rising tides. But is climate change really responsible for what's washing away their world?

Like the earth's climate, the world's oceans have also warmed one degree Fahrenheit. When water heats up, it expands and rises. Scientists call it thermal expansion. Global sea levels rose about 1.8 millimeters a year in the 20th century. But since 1993, an even higher sea level trend of 3.1 millimeters a year has been recorded.

While difficult to measure exactly how much, scientists believe part of the rise is due to melting glaciers and ice sheets, like the ones we saw in Greenland. That melt is picking up steam, raising concerns for even more sea level rise, putting the Carteret Islands and others like it in further jeopardy.

You can see some of the trees here. I mean these actual trees, look what happened. Did the water just knock them down?

UNIDENTIFIED MALE: The water just knocked them down. And maybe in two, three years, this whole area will be just completely washed out.

GUPTA: I met with one of the island's chiefs, Bernard Tunim (ph). He was born here, as were his parents and grandparents. He worries that he may no be able to stay much longer. Why is it happening?

UNIDENTIFIED MALE: Now because of the understanding of global warming, we believe what is melting in the Arctic or the place where there's ice. And when that melts, the water is affecting us because the level of the sea is rising all of the time.

GUPTA: But it might not be that simple. What we saw from above the islands was a coral reef that appeared bleached and dying. Reefs serve as natural barriers to heavy storm surges that can swamp low- lying lands. So is it rising seas or the loss of coral that's causing the Carterets to sink? When we come back, our investigation continues beneath the surface.

(COMMERCIAL BREAK)

COOPER: I'm Anderson Cooper in Rancho Bernardo, California. PLANET IN PERIL continues in a moment.

Here's the latest on the California wildfires. President Bush is going to visit the region tomorrow. Today, he officially declared southern California a major disaster area. In San Diego County alone, the damage already tops an estimated $1 billion. The biggest fire, the witch fire, has already destroyed more than 905 homes and other buildings. Thousands of evacuees have gathered in San Diego's Qualcomm football stadium. Amazingly, there's no shortage of food or diapers or even toilet paper. That is good planning on the part of local officials. That doesn't mean these people can relax, however.

(BEGIN VIDEO CLIP)

LETICIA DECKERT, EVACUEE: It's stressful, very stressful. We're going to go home now. We're told that the fire area is under control. But it's just nerve wracking.

(END VIDEO CLIP)

COOPER: They don't know what's happening to their homes, miles away in the line of fire. Another update about the fire in 15 minutes. I'm Anderson Cooper. PLANET IN PERIL continues after this break.

(COMMERCIAL BREAK)

GUPTA: We're flying back to the Carteret Islands in the South Pacific to try and solve the mystery, why the islands here are disappearing. Is it rising sea levels or something else entirely?

After two days here, there was only one place left to explore, underwater. Chief Bernard (ph) takes us out by boat to the coral reef. He tells us we're the first journalists to dive the reef. With dive gear, we head down 60 feet.

What we see is startling, a gray landscape with little marine life. Healthy coral reefs act as protective barriers to islands, helping slow destructive storm surges while providing food and shelter for marine life. This reef is dying, which means less protection from storms and fewer fish to eat.

So from the air, we can look down at the coral, it certainly looked like a lot of it was dead. We actually just dove down. And when we got down there, we saw evidence of what seemed to be bleaching. We actually saw entire sheets of coral that seemed to be completely dead and washed out. Now, there was some evidence of live coral, but it was interesting that some of that appeared to be dying in the process as well.

Coral bleaching, scientists say, is a result of global warming, and it's happening in oceans around the world. Increased temperature and light cause the coral to expel the algae cells that live in their tissues. When the algae leaves, coral takes on the bleach coloring. Many coral reefs often die after bleaching.

And that, it seems, is what's happening to the Carterets. Global warming might be causing a slight rise in sea levels, but its largest effect here is damage to the coral reefs that protects these islands.

Combined that with the fact that Carterets sit on top an ancient volcano, that over time collapses inward and they could be sinking naturally as well. But none of those reasons mean very much to Rose. Her home is disappearing. Her future is at best uncertain.

I can see the water from here, Rose, and they say that the water is actually going to cover this entire island within a few years. What's going to happen to you?

UNIDENTIFIED FEMALE: I will have to stay.

GUPTA: But it's sinking.

UNIDENTIFIED FEMALE: No, it is definitely sinking but the life here is too valuable to leave.

GUPTA: We're going to take you next from a place that suffers not from too much water, but from not enough, Lake Chad. It used to be one of the largest lakes in the world, but it's disappearing.

It was once the sixth largest lake in the world, covering more than 10,000 square miles. But over the past 40 years, Lake Chad in central Africa has shrunk by 90 percent. Where there was water, now only sand.

UNIDENTIFIED MALE: Here we are suffering. We are suffering from the climate change. It's obvious here. We are fighting for survival.

GUPTA: We're here because we are told this is one of the most concrete examples of climate change anywhere in the world. People are dependent on their water and they are not getting enough. Less water also means fewer and smaller fish and as a result, the people are getting smaller as well.

But the water crisis may be more than just climate change. We wondered, did something happen to the once-mighty river that feeds Lake Chad? We decided to go there and try to get some answers along the way. Lake Chad borders four different countries - Chad, Cameroon, Nigeria, and Niger.

UNIDENTIFIED MALE: Up to this wall --

GUPTA: Our guide is Anadatiega (ph). He's a native of Niger. He has seen the dramatic changes firsthand.

UNIDENTIFIED MALE: The struggle today is how to get food. People do not have enough food. Even if they had enough food in terms of quantity, the quality is decreasing. And the diet of people is becoming less balanced.

GUPTA: As the wetlands manager, he spent the last four years working with the Lake Chad basing commission, a group that's trying to save the lake.

There are roughly 37 million people who rely on Lake Chad. And they are quickly depleting what water is left. Much of it is siphoned off to irrigate crops.

The lake has dried up before. Natural changes in the earth's orbit and the tilt of the sun 10,000 years ago caused the climate to shift, bringing out a long drought.

But that's not what is happening today. The consensus among scientists is something is different. From the air, it's clear the lake is dropping. And this is what it looks like here on the ground. Sand all around me. Look at this dry, cracked, parched earth.

The water here used to be at least six feet high and now all around me, there's nothing. I'm standing in Nigeria, what used to be the middle of Lake Chad. Believe it or not, this is the rainy season.

And that, scientists say, is a direct result of climate change. As the earth gets warmer, moisture in the atmosphere that used to fall as rain, instead evaporates. Water held in the soil and in lakes is also disappearing.

It's clear the weather patterns here have changed. The summer rains no longer able to replenish the lake so many people have come to depend upon. Climate change is making a bad situation worse.

Ironically, Africa is the lowest carbon emitter in the world. Yet due to its dry climate, scientists say it's the most vulnerable to the effects of climate change. Combine that with the fact that Africa's population is growing faster than anywhere else in the world. The pressure on dwindling resources becomes clear.

We press on. And after two long days of driving in the sand, we are closing in on the source of Lake Chad and hopefully to the answer as to why exactly it's disappearing. It's 114 degrees in the desert, and things take a turn for the worse. When we come back -- trying to break free from Africa's sinking sand.

We are stranded. We are stranded as it turns out right now.

(COMMERCIAL BREAK)

COOPER: I'm Anderson Cooper in Rancho Bernardo, California.

PLANET IN PERIL continues in a moment.

I want to update you, though, on tonight's breaking news.

Fifteen separate wildfires are now burning in California. Crews have largely contained many of the fires north of San Diego. And all five fires in Los Angeles County are about 50 percent contained or more.

Some of the nearly one million evacuees are getting a look at what's left of their homes this evening. San Diego County came within moments of suffering a massive power blackout this afternoon, crews managing to clean ash and fire retardant off of lines strung across 70 towers and restore power just before the only other major power link to San Diego went offline -- a close call. Power company officials are pleading for conservation.

(BEGIN VIDEO CLIP)

MICHAEL R. NIGGLI, CHIEF OPERATING OFFICER, SAN DIEGO GAS AND ELECTRIC: There are a lot of people returning to their homes right now. And that is a wonderful, wonderful story. But that also means that the power demand on the grid will go up. Again, please conserve.

(END VIDEO CLIP)

COOPER: Electricity is just one of the wild cards here tonight. The weather is another.

Meteorologist Chad Myers has the latest forecast -- Chad.

CHAD MYERS, CNN METEOROLOGIST: Anderson, the smoke still billowing from all of these fires.

The latest satellite picture showing still blowing offshore, although lightly now. The winds are way down, down to only six, seven, five miles per hour, even down near by San Diego one-mile-per- hour now.

So, what does that really spell for the forecast? That means the smoke is going to get thicker and not going to get blown way. The forecast for tonight, no real gusts over about 20 miles per hour.

And, tomorrow, the winds lay down completely. And, by Friday, the winds actually blow back onshore, which means all of that smoke that's out there in the ocean will be pushed back into L.A., back into San Diego, and all the way through east and into the valleys, back through Twentynine Palms, maybe through Yuma.

Phoenix, you may be smelling smoke by Friday afternoon. And that's the smoke from L.A. that went out to the ocean and then was brought back in with the east winds turning to west winds. Those west winds, Anderson, could fan the flames a little bit for the end of the week, but, so far, about 15 to 20 miles per hour -- Anderson.

COOPER: Good news that, Chad. Thanks.

I'm Anderson Cooper.

We're going to have another update on the fires in 15 minutes.

PLANET IN PERIL continues after this short break.

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

COOPER (voice-over): Greenland's ice sheet, 40 percent of it gone in the past 40 years. Alaska's sea ice, melting and possibly threatening the future of the polar bear. The people of the Carteret Islands literally being washed away. But is it a crisis or hype? What are we doing to our natural world?

(on camera): It's so disturbing to see this.

JEFF CORWIN, HOST, "THE JEFF CORWIN EXPERIENCE": It is absolute, utter devastation.

COOPER (voice-over): What are we doing to ourselves?

DR. SANJAY GUPTA, CNN SENIOR MEDICAL CORRESPONDENT (voice-over): It's 114 degrees, and we're stuck in Central Africa. We're trying to get to the source of Lake Chad to investigate why it's disappearing. So far, getting there is proving anything but easy.

There are no winches out here to free our trucks, just the bodies of our entire crew. We finally break free, as we close in on the Chari River, Lake Chad's source. We stop at a fishing village called Duram Baga (ph) in Nigeria. It used to sit on the banks of Lake Chad. Over the past 30 years, the water has steadily receded.

(on camera): We're in a fishing community here. What is the impact on the people that live here?

UNIDENTIFIED MALE: You know, the impact is really obvious. And here, as you can see, we don't have healthy fish. This species of fish can grow up to 60 kilograms, and, today, you see, they just a few grams.

GUPTA: So, this used to be up to 60 kilograms?

UNIDENTIFIED MALE: Yes.

GUPTA: And it's just a few grams now?

UNIDENTIFIED MALE: Yes, yes. This means there is no healthy wetlands, so no healthy fish, so no healthy people. No food for people.

GUPTA: So, are they getting sick or...

UNIDENTIFIED MALE: Yes, they are getting sick just because of food shortage.

GUPTA (voice-over): Some of the children here are clearly malnourished. And the poor diet makes all of them vulnerable to disease.

We continue our journey, a bumpy ride for another few hours. Finally, we arrive at the Chari River.

(on camera): Here's one of the best examples of what's happening to the water here. You're looking at the River Chari here. This is one of the largest rivers that actually supplies water to Lake Chad.

And that is Lake Chad. This used to be a mega-lake, one of the biggest lakes in the world. So, really, that's all that is remaining of it now. And, right here, between that land over there and this land over here, this is the river mouth. That's all -- the water that supplies the lake is all coming through here. There's not very much left anymore. And that's what's happening to the lake. All this land is appearing and the water is disappearing.

(voice-over): Even the Chari River, the source for this once great lake, is evaporating.

As Lake Chad disappears, many have nowhere else to go. The Lake Chad Basin Commission has a plan to divert water from the Congo River, but it remains controversial and unfunded. There are no easy solutions.

Heading back towards shore from Lake Chad, our journey here is coming to a close. What we found is that Lake Chad's disappearance isn't just climate change or simply overuse, but, instead a combination of both, with tens of millions of people competing for a resource that is literally evaporating.

What is left is a daily struggle. But, somehow, Anata (ph) holds out hope.

(on camera): But you still are optimistic, despite everything that we talked about this today, that water is going to cover all this once again?

UNIDENTIFIED MALE: Yes, it will. And, as we heard from the fisherman himself, he said, water will come. So, everybody here keep hope.

GUPTA: From what we have seen in Greenland, Alaska and Africa, the Earth's climate is clearly changing. It's not a theory. It's a fact. But what's causing those changes? The majority of the scientific community says it's mankind. But there are powerful voices who say otherwise.

SEN. JAMES INHOFE (R), OKLAHOMA: And, with all the hysteria, all the fear, all the phony science, could it be that manmade global warming is the greatest hoax ever perpetrated on the American people? I believe it is.

COOPER (voice-over): If you thought the debate over what's causing the Earth to warm was settled, think again.

INHOFE: I don't want to be rude, but, from now on, I'm going to ask...

COOPER: James Inhofe, Republican senator from Oklahoma, is the loudest voice with probably the biggest platform who questions whether man is responsible for climate change. His position has led to some intense political theater.

AL GORE, FORMER VICE PRESIDENT OF THE UNITED STATES: If I could complete my answer.

INHOFE: Well, if you do, then my time has expired. Are you aware of that?

GORE: Well, I can't help that, because you went on for a long time. But I would like to...

(CROSSTALK)

INHOFE: No, I have 15 minutes.

(CROSSTALK)

INHOFE: You, sir, had 30 minutes. I have 15. You have got to let me...

COOPER: This year, 2,000 scientists on the U.N.-sponsored Intergovernmental Panel on Climate Change concluded, with 90 percent certainty, that man is responsible for global warming.

They were awarded a Nobel Prize for their work. But Inhofe questions the motives of those who say man is responsible for global warming.

INHOFE: This whole idea of global warming is something that has been brought up by certain groups who have a lot to benefit from it, and has nothing to do with real science.

COOPER: Nothing to do with science and everything to do with money. Support human-caused climate change, Inhofe's thinking goes, and you get more funding.

But Inhofe's critics question his funding. The second biggest contributors to Inhofe's Senate office are energy and natural resource companies.

We wanted to talk to Senator Inhofe about those contributions and his position on climate change. But, after agreeing to an interview with us, he canceled.

But the debate is not just political. Some scientists question the data and the models that predict climate change.

Pat Michaels is one of them. He agreed to sit down with us.

(on camera): Do you think climate change is a hoax?

(END VIDEOTAPE) (COMMERCIAL BREAK)

COOPER: I'm Anderson Cooper, Rancho Bernardo, California.

PLANET IN PERIL is going to continue in a moment, but, first, the latest on the wildfires.

Firefighters are getting a grip on the wildfires around Los Angeles. But those here in San Diego County are still raging out of control, threatening more than 8,000 homes right now. So far, flames have burned almost 700 square miles. The death toll remains only one.

Authorities credit massive evacuations with savings lives. A huge fire years ago killed 22, when not as many people were ordered to evacuate.

Police used a reverse 911 calling system to order hundreds of thousands to leave their homes. But those in Qualcomm Stadium are still worrying about those homes.

(BEGIN VIDEO CLIP)

TRUDY MCCUNE, EVACUEE: I feel kind of bad because I'm hoping that I don't lose my home, but then I feel bad because I know a lot of people that have lost their homes.

(END VIDEO CLIP)

COOPER: And that is the latest here in Southern California -- another update in about 15 minutes.

I'm Anderson Cooper.

PLANET IN PERIL continues after the break.

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

COOPER (voice-over): The Earth is warming. The ice sheets are melting. Lakes are evaporating. The question is, why? Are human beings responsible? And, even if we are, is it a crisis or just hype?

Pat Michaels was Virginia's state climatologist for more than a decade and a professor at the University of Virginia. He's also a so- called climate change skeptic.

(on camera): Do you think climate change is a hoax?

PAT MICHAELS, PROFESSOR, UNIVERSITY OF VIRGINIA: Oh, heck no. Human beings are changing the climate. I think the warming that we are seeing is at -- definitely at the low end of the projection range.

COOPER (voice-over): A projection range based on computer models. That, he and other skeptics like him say, is a fundamental problem. MICHAELS: The problem is, we have these things called computer models. And that's all we have for the future. And when we look at these computer models, one of the things we see is that they tend to predict more warming than is occurring.

COOPER: That's true. Some estimates do have the Earth warming more than it currently is. And it's an illustration on the difficulty of deciphering the debate. Both sides accuse each other of cherry- picking data. Models, you see, also underestimated our changing climate.

Remember the sea ice you just saw in Alaska? Computer models had one million square miles of it melting by the year 2050. It reached that level this year.

Even so, not to fear, says Michaels. Animals like the polar bear and humans will simply adapt.

(on camera): The scientists who are warning of huge changes within our lifetime, are those just scare tactics?

MICHAELS: I think a lot of people have not looked at the adaptational responses that human beings have. Look on the United States, probably the most violent weather on Earth of any large civilized nature -- the number of tornadoes...

COOPER: Right.

MICHAELS: ... stunning. And big cities are in the way of these tornadoes. Death rates from tornadoes are going down, down, down, and down. Why? Adaptation.

COOPER (voice-over): Adaptations, he says, like stronger buildings, better warning systems.

While a scientific consensus says man is responsible for global warming, Michaels, like Senator Inhofe, says money is the prime motivator.

MICHAELS: You write a proposal and you tie it to climate change, you got a good chance.

JAMES HANSEN, DIRECTOR, NASA GODDARD INSTITUTE FOR SPACE STUDIES: You know, nothing could be further from the truth. And, in fact, I'm a good example of that, because when I first spoke out about this in 1981, I ended up losing my funding.

COOPER: Dr. James Hansen does not believe scientists are simply chasing funding.

Hansen, with NASA's Goddard Institute for Space Studies, was one of the first scientists to bring global warming into the public's consciousness in the 1980s.

HANSEN: We conclude that there is evidence that the greenhouse effect increases the likelihood of heat wave drought situations. COOPER: Hansen was nearly alone back then. But, today, he's brought the vast majority of the scientific community to his side. We are changing our climate, he says, and are risking a different planet. He rejects nearly all of the skeptics' points, from moderate estimates...

HANSEN: We're talking about several meters of sea level rise if West Antarctica begins to go unstable.

COOPER: ... to computer modeling.

HANSEN: That's another big misconception. The computer models are helpful, but they are not the primary source of information. It's the Earth's history that tells us, with the most accuracy and the most reliability, what the climate sensitivity is.

We have measurements of the atmospheric composition, very precise, from the bubbles of air trapped in the ice sheets as a function of time over the last 700,000 years.

COOPER: Climate science is clearly complicated and often controversial. Both sides of the debate know that.

For Jim Hansen, that makes the situation all the more pressing.

HANSEN: The nature of science is, you say, on the one hand, this and, on the other hand, that. And, even as the story becomes quite clear, we may not be making clear that we are really talking about a different planet. So, I think we are running out of time. We have really got to get started in the next few years, so that we are really on a different path.

COOPER (on camera): A different path, because we are destroying much of what remains of the natural world. And these are vast resources we are losing. They feed us, provide us medicine, and control our climate.

Jeff and I are now heading to Brazil's Amazon to see firsthand the battle for the world's greatest rain forest.

(voice-over): You're looking at one of the largest emitters of greenhouse gases in the world, the Amazon rain forest. How is that possible? How is it that a forest covering nine countries, home to 200 indigenous tribes...

CORWIN: This is one of my most favorite creatures right here.

COOPER: ... holding one-quarter of the world's species, can be a major contributor to climate change? Because it is, quite simply, under assault.

The carbon naturally stored in trees is released when they're cut down. And they're being cut down at a breathtaking rate. These are the men bent on stopping that. They're agents with IBAMA, the Brazilian government's environmental protection agency. This mission in a remote corner of Brazil has been in the works for over a year. The agents are heavily armed, but heavily outnumbered. Their job is daunting, something you can only appreciate from the air.

CORWIN: Just in the Amazon basin alone, it's 2.7-million square miles of habitat, and roughly 70 percent of that is right here in this extraordinary country, in the country of Brazil.

COOPER (on camera): Two-point-seven-million square miles, that's a little bit smaller than the continental United States.

CORWIN: Exactly.

COOPER: Huge.

(voice-over): But all of that is in jeopardy.

(on camera): It's so disturbing to see this.

CORWIN: It's just absolute, utter devastation and destruction.

COOPER (voice-over): Twenty percent of the jungle has been lost in the past 40 years.

(on camera): It seems, though, the problem is, once you get out to these remote areas, you can do just about anything. There are very few people watching over you.

CORWIN: These regions, when you're away from any bit of infrastructure, can be pretty lawless. And, basically, anything goes.

COOPER (voice-over): Anything goes. And the IBAMA agents know that.

It doesn't take long for them to pick up one of the illegal roads made by poachers. There's no telling what's around each corner. In the distance, the agents spot something suspicious. The truck slows, and guns are drawn.

(on camera): They have just found a truck with some people. Let's check it out.

UNIDENTIFIED MALE: (SPEAKING FOREIGN LANGUAGE)

(DOGS BARKING)

(END VIDEOTAPE)

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

COOPER (voice-over): In a wooden shack in a remote corner of the Amazon forest, armed men pore over maps and make last-minute plans. They are all here, more than 200 of them, to try to put a stop to the animal poachers and loggers who are tearing this forest apart. It's an effort led by IBAMA, Brazil's environmental protection agency.

(on camera): These officers from the federal police are teaming up with IBAMA agents, and they are about to go out on patrol. For IBAMA, secrecy is key. If word leaks out in this area that IBAMA is here, that they are going to be on patrol and launching a series of raids, then the illegal loggers will simply disappear into the -- the rain forest.

(voice-over): Official says more than 1,000 people have died in the past 20 years in battles over the Amazon's resources.

Agents get word over the radio there might be an encampment of illegal loggers nearby. So, they quickly pile into their trucks. Finding the roads made by the loggers is easy. What's not so easy is traveling them during the rainy season.

(on camera): These roads, as bumpy and -- and terrible as they are, what's even worse about them is that the roads are the conduit for the habitat loss.

CORWIN: Absolutely. This is basically the pathway for which the timber comes out.

COOPER: Illegally logged, for the most part?

CORWIN: Not all of it illegally logged, but a significant amount. Some statistics say that perhaps as much as 80 percent, to as little as 60 percent, is logged illegally.

COOPER (voice-over): And that adds up. In 2006, 5,500 square miles of Amazon forest was cut down, roughly the size of the state of Connecticut.

And that was a 25 percent decrease from the year before.

(on camera): It is politically correct to say you care about the rain forest, but why should someone actually care? I mean, if you're in New York or Iowa, what impact does the rain forest really have on your life?

CORWIN: Simply put, the survival of our species of human beings is directly dependent upon the survival of rain forest habitat. For example, 20 percent of the world's water is locked up in rain forest habitat, specifically the Amazon Basin.

COOPER (voice-over): Despite its value, the destruction of this habitat continues.

Brazil is the number one soy producer in the world. And it takes land to grow soy, land without trees. It's also the world's top beat exporter. Those two industries continue to expand, and they need land to do it.

But not all of the trees are cut down for big profits. Some are harvested by small farmers eking out a meager living.

(on camera): Wherever you go in Brazil, in the Amazon, you will find that, fire. This is a small fire set by a man who is cutting down a couple of acres of land. This is classic slash and burn.

(voice-over): Cutting down and burning trees not only clears the land; it releases nutrients into the soil, making the ground more fertile. It's an easy, but destructive way small-time farmers do business here.

Like so many areas we have seen around the world, poverty plays a big role in habitat destruction.

(on camera): This is really the front line of deforestation. Even though this land hasn't been cleared, it's going to be affected, and the animals living on it are going to be affected by the fact that there are people living just a few feet away.

CORWIN: Very much so. At first glance, it looks like a relatively healthy forest. But just listen. What do you hear?

COOPER: Not much.

CORWIN: Not much. No birds, no buzzing insects.

COOPER (voice-over): The World Conservation Union says the Amazon is home to nearly 1,000 threatened species of plants and animals. Ibama doesn't have nearly enough personnel to protect them all.

Back on the muddy and rutted roads with Ibama, agents continue to comb the forest for anything that looks out of place. They may have just found it.

(on camera) Every day Ibama agents go out on patrol and stop anyone they come across and question them about what they're doing in this biological preserve. They have just found a truck with some people. Let's check it out.

(voice-over) Their truck is broken down, and they say they need help. When agents find a hunting rifle, this man says they're only there to hunt one small animal. But his story doesn't add up. A quick search turns up a small arsenal.

(on camera) The guy has, like, what: one, two, three, four, five rifles.

CORWIN: He's got five rifles. He's got three machetes. He's even got a slingshot.

COOPER (voice-over): And a pack of hunting dogs.

CORWIN: These guys have all the classic tools of the trade when it comes to poaching wildlife.

COOPER: The men take us to their camp site, where they've already clear-cut the forest. The cooler is stocked with deer meat poached from the rain forest.

CORWIN: These gentlemen have been very, very busy.

COOPER (on camera): They said they were just out looking for small animals just to eat. Clearly, it's a larger operation than that.

CORWIN: Clearly, their motivation was a bit more insidious. These men are hunting not just for themselves. They're probably selling the meat, as well.

COOPER (voice-over): The men are arrested and charged with possessing arms and hunting in the preserve, charges that could get them ten years in jail.

(on camera) For Ibama, these arrests are a sign of help: one small victory in the ongoing battle to save the forest. These four men have been taken into custody. That means they won't be out hunting today, killing untold numbers of wild animals.

Ibama has been fighting this fight for several years now, but it wasn't until 2005 when a 73-year-old American nun changed the way Brazil protects its forests.

(voice-over) In the small town of Anapu, deep in the Amazon state of Para, Sister Dorothy Stang is everywhere. Sister Dorothy came to Anapu from her native Ohio in 1983. She said she was drawn to the Amazon to work with the poor.

SISTER DOROTHY STANG, NUN/CONSERVATIONIST: The only thing they know is survival farming. That's slash and burn.

COOPER: She started a sustainable development program, teaching locals how to live off the forest and at the same time preserve it. Her mantra: the death of the forest is the end of our lives.

STANG: Bring back new life to a land that was lost. It is possible. We can renew the forest.

UNIDENTIFIED MALE: Let's do it.

UNIDENTIFIED FEMALE: She may have looked like a little old lady to people from outside. But who lived with her, she wasn't a little old lady. She was a powerhouse of decision. And when she decided, she decided. And she would, you know, work to make it happen, her way.

COOPER: But her friend and colleague, Jane Dwire (ph), says those tactics earned Sister Dorothy some powerful and dangerous enemies.

Big ranching and logging companies were often in her sights. If they encroached on a peasant's land, Stang would report them to the government. As Sister Dorothy became more visible and successful, she started getting death threats. She refused, however, to be intimidated. (on camera) On February 12, 2005, Sister Dorothy Stang was walking down a path in the Amazon jungle. Suddenly, she was confronted by two men. Words were exchanged, and one of the men took out a gun.

Sister Stang didn't try to run away. Instead, she opened the Bible she was carry in her hand and read a passage from the gospel of Matthew: "Blessed are they who hunger and thirst for justice, for they will be satisfied." As she closed the Bible and turned to go, the gunmen opened fire.

(END VIDEOTAPE)

(COMMERCIAL BREAK)

COOPER: Here in Rancho Bernardo, California. PLANET IN PERIL will continue in a moment. First an update on the California fires.

They've destroyed nearly 1,600 homes and nearly a half million acres across seven counties here in Southern California. Fifteen fires are burning tonight. Arson investigators say one of them, the Santiago fire near Los Angeles, had three points of origin.

A $70,000 reward has been announced for information leading to the arrest of whoever may have set that blaze.

San Diego Mayor Jerry Sanders says the vast majority of the city is now open for people to return to their homes. There's at least a billion dollars in damage here in San Diego County alone.

I'm Anderson Cooper. At the top of the hour, we'll have a special edition of 360. PLANET IN PERIL continues right after this break.

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

STANG: (UNINTELLIGIBLE)

COOPER (voice-over): Early February 2005, Sister Dorothy Stang, an American nun from Ohio, leaves a meeting of peasant farmers, whose land she's helping to protect, and walks into the jungle towards her home. She never makes it there.

Two men meet her on a muddy path. Words are exchanged. The men draw weapons, but instead of running, Sister Dorothy opens the Bible she's carrying and reads them a passage. When she turns to go, they shoot her at point-blank range, leaving her in the mud to die.

Just days later, these two men confess to the murder. Police take them back to the scene, and they re-enact the brutal crime. They tell police they were paid $25,000 by ranchers, who wanted Sister Dorothy out of their way so they could continue illegally logging the rain forest. Four of the five men involved have been convicted in her murder, but the rancher who's believed to be the mastermind behind the plot remains free on bail.

But killing Sister Dorothy did not have the result some ranchers may have hoped for.

UNIDENTIFIED FEMALE: They thought that killing her would end it. Well, on the contrary. It did exactly the opposite. And the people are stronger than ever, and we do not intend to leave here.

COOPER: The Brazilian government responded by setting aside more than 30,000 square miles for protection. Sister Dorothy's death became a symbol, not only for the rain forest, but also for the protection of the people who call it home.

There are some 100,000 indigenous people living in Brazil's Amazon rain forest. We've arranged to visit one small tribe, the Kraho Indians in the Tacantin state of Brazil.

We're told by the chief it's the first time a helicopter has ever landed in the village.

(on camera) These are Kraho. They're an indigenous people here in the Amazon rain forest. There are about 200 or so who live in this village. It's a protected reserve who just arrived here to find out how they're struggling to protect their habitat.

In Kraho, they always celebrate the arrival of visitors with a ceremony. They're saying that very few people come to this village, very few outsiders. So to welcome us, they want to baptize us. That's the term they're using. They want to go in and give us local names, names in their language, and also give us tribal markings.

(voice-over) They name Jeff Running Deer.

CORWIN: Thank you. I'm honored by that. Thank you.

COOPER: And me, I'm Regal Bird.

(on camera) Thank you very much. I'm very honored. Thank you.

(voice-over) After the festivities, we join the tribe for a meeting, where they share grim news of what's happening to their home. A tribal elder tells us they fight hard to protect their land and keep their traditions alive. He says they're angry and scared by what's happening.

There are about 3,000 Kraho Indians left in the Amazon basin, spread out in villages across 750,000 acres of protected land, given to them by the government.

But part of the Krahos' land has already been illegally clear- cut, and there's little to no law enforcement to stop it. Kraho are trying to take matters into their own hands. (on camera) The Kraho are very concerned about illegal logging on their territory. Every day they go out on patrol armed with bows and arrows, just making sure no one is cutting down trees.

(voice-over) They say they've run off poachers on these patrols before, where their territory is huge and their numbers small, so the poachers keep coming back.

As hunters, gatherers, and farmers, the Kraho rely on the rain forest for food, water, shelter, everything. The Amazon is a vital resource for the world, as well. As Jeff mentioned earlier, the Amazon basin holds 20 percent of the world's water.

At least 80 percent of the developed world's diet comes from the Amazon, mostly from the soy and beef industries, not to mention the tropical oils that are key ingredients in cosmetics like perfumes and shampoos.

It's a sort of natural medicine chest, as well. The National Cancer Institute says that, of the 3,000 plants that fight cancer cells, 70 percent of them are found in the Amazon rain forest.

But despite all of that, the rain forest is being pillaged at a rapid rate. Roughly 5,500 square miles are lost every year.

Back on patrol with the Kraho, we hike for hours through their territory but never find any illegal activity, at least not today. They will go out again tomorrow, however, trying to do whatever they can to stop their home and their way of life from disappearing.

UNIDENTIFIED MALE: (UNINTELLIGIBLE)

COOPER (on camera): There's a pattern here. We see it, not just with the Kraho but also with others we've met in Cambodia and China and Africa. The disenfranchised usually bear the bankrupt of environmental degradation.

And that just doesn't happen in remote corners of the globe. It's happening right here in America.

(voice-over) For Valentin Marroquin, Manchester, Texas, seemed a fine place to grow up. It was a tough neighborhood, but he had friends and plenty of places to play.

His mother, Rosario, was just happy she'd found somewhere free from the violence and drugs that plagued other low-income neighborhoods. Her children were safe; at least, that's what she thought.

ROSARIO MARROQUIN, MOTHER OF VALENTIN: My worst fear as a parent was losing my child somewhere. A park, crowded place. That's what parents fear. You always think of something like that. You don't think your child coming down with cancer.

COOPER: At just 6 years old, her oldest child and only son, Valentin, was diagnosed with leukemia. R. MARROQUIN: ... I am feeding (ph).

VALENTIN MARROQUIN, CANCER PATIENT: Cook (ph).

R. MARROQUIN: That's all I remember, just time stops.

COOPER: The very next day, Valentin began chemotherapy.

Unable to protect her little boy, Rosario Marroquin felt helpless, as she started looking for answers. She never could have guessed where she'd find them.

(END VIDEOTAPE)

(COMMERCIAL BREAK)

COOPER: I'm Anderson Cooper in Rancho Bernardo, California. PLANET IN PERIL continues in a moment. First an update on the wildfires.

They continue to rage around Lake Arrowhead. This is the Running Springs fired. But the winds are dying down, and that gives firefighters a chance to possibly gain the upper hand.

San Diego County dodged a major bullet today, barely escaping a massive power outage. Flames from the Harris fire threatened the power lines. At this hour many people are being allowed to return home. Power companies have asked people, however, to conserve power.

Only a few hours until President Bush flies to California. Today the president declared fire-ravaged Southern California a major disaster zone. Damages estimates $1 billion, and we're talking about just in San Diego County. Those numbers expected to climb.

My colleague, Rick Sanchez, is covering one of the two big fires now happening in this area. He got right up to one of the fire lines today. He joins us from Spring Valley by the Harris fire -- Rick.

RICK SANCHEZ, CNN CORRESPONDENT: Yes, the Harris fire. As a matter of fact, you mentioned the Harris fire just moments ago, Anderson. It's the fire that did some of the power outage damage. It also has to continue to do a little bit of damage in that area just where I'm pointing right now.

It's the outer southern edge of the fire. And what's going on over there is they 're trying to essentially close the door on that fire. In fact, we've got some pictures we can show you. I think you might be seeing those right now.

This is the area. It's called Deer Horn Valley. And when we first went up there, they had a warning to residents. But while we were on the way up the mountain, that warning changed, and it turned into an evacuation order.

So they started going door to door and trying to get the people out. That's just how big that fire suddenly got out there. That's the last remnant of this thing, they hope, at least in terms of this side of the fire. They hope to be able to get that thing out, at least, during the next couple of days, but they've got a ton of crews up there.

Most of those strike teams, as we've seen them working in the area with the battalion commander.

We'll be on it throughout the night. We'll be following it for you, Anderson. Back to you. That's it for the Harris fire.

COOPER: Rick, thanks very much. Going to have a special hour on the fire, starting at 11 p.m. Eastern Time. That's in about ten minutes from now. We're going to take you right to the front lines of the Harris fire with Rick Sanchez.

Also, I spent the day out there. We'll show you the eastern edge of that fire.

PLANET IN PERIL, however, continues after this break.

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

COOPER: Six-year-old Valentin Marroquin went from healthy one moment to a leukemia patient battling for his life the next.

R. MARROQUIN: All right.

I would always hear him say, "When I grow up, I want to do this." He'd always say that. Or "I'm going to be chief of police" since he was little. Or "Mom, when I'm this age."

And I would always say, is he going to get there?

COOPER: His mother, Rosario Marroquin, started searching for answers, and she kept coming back to their neighborhood and the stench that often embellished it.

R. MARROQUIN: It was a stinky neighborhood, but we'd gotten so used to it that we don't know. That's just how we smell.

COOPER: This stinky neighborhood because it sits next to the Houston Ship Channel, the largest petrochemical complex in America. Here, oil refineries and petrochemical companies pump hazardous pollutants into the air.

A study released in 2006 showed the concentration of known carcinogens benzene and 1-3-butadiene was significantly higher. At least 20 times greater for 1-3 butadiene than any other city in the U.S.

R. MARROQUIN: And our kids get sicker in the country. But this has something to do with it. COOPER: And that may be true. Earlier this year the University of Texas released a study showing kids living within two miles of the ship channel had a 56 percent greater chance of getting leukemia. A 56 percent greater chance.

While there's no clear-cut link. It's the first study showing the association between the ship channel's air quality and childhood leukemia.

The risk is not just cancer. Benzene and butadiene are also known to cause other serious health effects like respiratory diseases and birth defects.

So if we know all of this, why is it happening? For one thing, weak laws. And we'll go into that in a second.

But the other reason, says environmental law professor Tom McGarity (ph), is because of race. Ninety percent of the people who live in the Marroquins' neighborhood are Hispanic.

UNIDENTIFIED MALE: If these plants were emitting these kinds of levels in River Oaks, it wouldn't be happening, I promise. I can tell you that right now.

River Oaks is the area where all the millionaires live.

COOPER: Activists call it environmental racism and say it's not just happening in Texas. Thailand, Cambodia, Madagascar, Chad, Brazil. In each place the poor and disenfranchised are usually the ones bearing environmental burdens.

It happens there, and it happens here. In 2005, the Associated Press found African-Americans are 79 percent more likely than whites to live in neighborhoods where industrial pollution is suspected of posing the greatest health danger.

UNIDENTIFIED FEMALE: How do we improve the quality of life for everybody?

COOPER: Tamara Carter (ph) is the founder of the Sustainable South Bronx, an organization that fights environmental racism in New York and around the country.

UNIDENTIFIED FEMALE: Right now race and class really determine where you find the good things, like parks and trees, or where you'll find the bad stuff, like waste facilities and power plants.

COOPER (on camera): The argument against your position is an economic argument. Most often, it's: "Well, look, it's cheaper to have plants in this neighborhood than it is anywhere else in this very expensive city." So...

UNIDENTIFIED FEMALE: You think you're making the argument that, you know, it's better to have it up here the because real estate values are so low. But think about the other kind of costs associated with it, that add up. COOPER: Health costs?

UNIDENTIFIED FEMALE: Yes.

COOPER: Crime?

UNIDENTIFIED FEMALE: Yes. Somebody is paying for it. We all are.

COOPER: But Carter (ph) points out the people whose health is in danger, whose quality of life is degraded, more often than not remain silent.

UNIDENTIFIED FEMALE: I don't care if anybody in this neighborhood, like, never understands what global warming is. The point is there are people out there that are making decisions on our behalf that do and are deciding not to do anything about it.

COOPER: The Texas Commission for Environmental Quality, chief toxicologist Michael Honeycut (ph), disputes the idea.

UNIDENTIFIED MALE: One-third less pollution in the Houston Ship Channel this year compared to last year because of our approach of bringing companies in, telling them what we want and we're seeing those reductions. This is an issue of timing.

Scientists are generating data all the time. Something today -- you know, we find out today that something is not as safe as we thought it was or, well, something is safer than we thought it was.

BILL WHITE, HOUSTON MAYOR: Nobody has the right to chemically alter the air that somebody else breathes without that person's consent. It is not right.

COOPER: Houston Mayor Bill White has pledged to reduce the level of air toxins for those communities, even if it means playing hardball.

WHITE: We will have both a political and a legal battle with the industry until we get widespread agreement for them to do stuff.

COOPER: Tough talk, but here's something that might surprise you. When we talked to the companies in the ship channel, they pointed out that they've started voluntarily limiting their emissions, and they haven't broken any laws.

And that's true. There's actually no law, no ambient air standards, either state or federal, requiring companies to limit the amount of hazardous air pollutants they pump out.

There is an effort under way to get a law passed in Texas, but Professor McGarity (ph) says it's going to be an uphill battle, because when it comes to the oil industry here, old habits die hard.

UNIDENTIFIED MALE: That's going to be reflected at the top among the political appointees, who are more a part of this -- shall we say -- wild west culture where anything goes.

COOPER: A wild west culture where kids like Valentin Marroquin pay the price.

Now 10 years old, Valentin is in remission and doing well. The Marroquins say they can't leave here because they can't afford it. But they can't lock their children inside either.

R. MARROQUIN: When you're sitting out there, when you're watching them play, you think, "Is it going to happen? Are they bringing it in now?"

COOPER: Valentin still loves his neighborhood and playing outside. He just has one request.

V. MARROQUIN: To change the pollution to somewhere else. Somewhere there's no animals or no people who live there.

(END VIDEOTAPE)

COOPER: Investigating our PLANET IN PERIL has taken us to 13 countries on 4 continents. We've met literally hundreds of people along the way, some of whom you've been introduced to over the past two nights.

Everywhere we've gone, we've been told the same thing. None of what's happening is occurring in a vacuum. In all these places, all these problems are interconnected.

When we come back, the lessons learned.

(COMMERCIAL BREAK)

(BEGIN VIDEOTAPE)

COOPER: If you're going to find out more information about the topics discussed tonight, or find out what you can do to get involved, check out our impactor world website at cnn.com/impact.

Investigating our PLANET IN PERIL has taken us to 13 countries on 4 continents. We've met literally hundreds of people along the way, some of whom you've been introduced to over the past two nights.

Everywhere we've gone, we've been told the same thing. None of what's happening is occurring in a vacuum. In all these places, all these problems are interconnected.

In the Amazon along poacher's trails, in hidden villages, you can smell the smoke from the burning forest.

From the air you really get a sense of just how much of the rainforest has already been destroyed.

You can see the scars made by man. Plants and animals lost forever. Gases released warm the world. The icy expanse of Greenland, land and sky seem frozen forever. The danger is hard to see with the naked eye. The ice melts, the seas will rise. How much, how fast, a matter of debate; but tens of millions will be affected in this century.

CORWIN: As the Arctic changes under the effects of climate change and global warming, these very well could be one of the creatures most greatly affected.

COOPER: Already polar bears' behavior is changing. Already small islands slip beneath the sea.

GUPTA: They say that the water is actually going to cover this entire island. What's going to happen to you?

UNIDENTIFIED FEMALE: I will have to stay. The life here is too valuable to lose.

COOPER: More people are born, economies boom. We consume and grow more each passing year. By 2050, there will be 50 percent more people on the planet than there are right now.

In America, the discussion seems mired in politics. Skeptics, believers, liberals, conservatives; it all seems so theoretical. Environmentalism: the pet project of the rich, the cause for celebs.

We traveled the world and the issues are real.

UNIDENTIFIED MALE: The fact is that a minimum of 20 percent of all global emissions are coming from destruction of tropical forests.

COOPER: Struggles for land, fights over resources, people drink from polluted rivers in China and die in broken villages invisible from the gleaming towers of Beijing.

In Asia and Africa, animals and plants are ripped from the forest, species disappearing at a thousand times the natural rate of extinction.

What should be done? What can be done? That's where the real debate is now. We set out to report, not be advocates, no agenda. You've seen the front lines, the facts on the ground. Overpopulation, deforestation, species lost, climate change. Nothing happens in a vacuum. What happens in one place now affects us all.

(END VIDEOTAPE)

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