Former Vice President Al Gore delivers his message about global warming.

For the past 20 years, former Vice President Al Gore has been traveling the world speaking about global warming, a passion of his since college. In 2006, his lecture was made into the documentary An Inconvenient Truth—which went on to win an Oscar® for Best Documentary and is currently the fourth highest grossing documentary of all time.

In his lectures, book and documentary, Gore explains that if we continue to ignore what we are doing to our planet, we risk destroying the very future of our civilization. And the former vice president says that we must act before it's too late.

"Some of the leading scientists are now saying we may have as little as 10 years before we cross a kind of point-of-no-return, beyond which it's much more difficult to save the habitability of the planet in the future," Gore says.

"I believe that everybody should see [An Inconvenient Truth]," Oprah says. "You should get it for your friends and family this holiday season."
Former Vice President Al Gore explains how global warming happens.

It's been a hot topic lately, but what exactly is global warming?

First, it's important to understand that the atmosphere is extremely thin. "The late Carl Sagan used to say if you had a globe with a coat of varnish, the thinness of that varnish relative to the globe is similar to the thinness of the atmosphere to the planet," Gore says.

That atmosphere, which is just a few miles above the Earth's surface, traps some amount of the sun's energy, or light radiation, as it hits the Earth. "That's a good thing, the natural trapping of [the sun's radiation], because it keeps the temperatures within comfortable boundaries," Gore says. While other planets are either much too hot or much too cold, Earth is just like Goldilocks—just right for life.

As humans add pollution like carbon dioxide (also known as CO2) into the air, the Earth's atmosphere becomes thicker. The thicker atmosphere traps more of the reflected radiation, raising overall temperature. This process is what we call "global warming." Other major factors adding to global warming, Gore says, include the burning of coal, oil, gasoline and forests.
Former Vice President Al Gore explains that global warming isn't natural.

We feel rising and lowering temperatures throughout the course of our seasons. Couldn't the rising temperature of the Earth just be part of a natural up and down cycle?

Gore agrees that the planet's temperature has indeed experienced up and down cycles, but he says the current up cycle is too extreme. "It's way off the charts compared to what those natural fluctuations are," he says.

No place is immune to global warming, Gore says. "Of the thousand largest glaciers on every continent, 997 of them are receding," he says. "And it's not seasonal."

"Scientists say if we let it get that high on the warm side it would be an utter catastrophe, and it would be unethical and immoral where our children are concerned."
Former Vice President Al Gore says the North Pole is melting.

As carbon dioxide levels explode all over the world, the effects are most obvious at the North and South Poles.

For the past 50 years, the U.S. Navy has used submarines to patrol underneath the ice at the North Pole. These submarines can only surface where the ice shelf is less than three feet thick, so the Navy must routinely measure the thickness of the Arctic. Gore says their records show that "starting in the early '70s, [the ice shelf] started declining rapidly, both in the extent and the thickness. The North Pole is melting."

One consequence of this, as shown in An Inconvenient Truth, is a decline in polar bear populations as they drown. "They live on the ice and now the ice is sometimes 60 miles from the land. And the distance between the ice floes is very large, and so for the first time now in significant numbers they're finding them dying by drowning. ... Something similar is happening to the penguins near the South Pole."

Additionally, the melting North Pole could lead to even more global warming. "It's also really dangerous for us to have this big expanse of open water at the top of our world," Gore says. "Normally that's like a giant mirror. It's one of the ways the planet cools itself. But as it melts, the open ocean absorbs all that heat."
Global warming has damaged Shishmaref, Alaska, as seen in 'Everything's Cool.'

One place that already feels the effects of the melting North Pole is Shishmaref, a small Alaskan village just south of the Arctic Circle. The Inupiak people have lived here for generations, but in the past 30 years, they've witnessed dramatic changes.

As illustrated in the documentary Everything's Cool, warming temperatures are causing the icy barriers that once protected Shishmaref to form later in the season. This leaves the village vulnerable to fierce waves that pummel and eat away at the coastline.

As a result, entire foundations of houses have been destroyed as the ground has receded into the sea. Already 18 houses have been relocated to higher ground and rising water could eventually engulf the entire island. The estimated cost to relocate the village is $100 million.

Shismaref isn't alone. Gore says there are 180 towns in Alaska that face similar threats from rising sea levels.
Former Vice President Al Gore discusses the melting ice shelves in Antarctica.

Just as the North Pole is melting, so is the South Pole.

A map of Antarctica shows what appear to be black dots in the middle of the continent. These, Gore says, are pools of water. Initially scientists assumed that these pools would freeze and fill up with ice. Instead, they burrow like termites all the way through the ice "and make it like Swiss cheese," he says.

Larsen B, an enormous ice shelf in Antarctica, was thought to be safe for at least 100 years despite global warming. After all, it had already been there for tens of thousand of years. "But starting at the end of January 2002, in a period of 35 days, it completely broke up," Gore says. "They were shocked. The scientists still haven't gotten over that."

When land-based ice like the Larsen B ice shelf falls into the sea and melts, Gore says it raises sea levels much more rapidly than the slow melting of mountain glaciers.

"Back at the time in the late '70s when we first started having hearings on this, a scientist said, 'If you start seeing ice shelves break up [in Antarctica], watch out,'" Gore says.
Former Vice President Al Gore

Greenland faces similar problems. "They're worried because it's the same thing they saw in Antarctica on top of this ice shelf that broke up," Gore says. "They now know that these pools drill down through the ice like termites."

The difference between Greenland and Antarctica is that Greenland is not floating ice. Below the ice is bedrock. As the ice melts, it creates a destabilizing film between the ice and the rock. This destabilization, similar to a hydroplaning car, has resulted in a dramatic increase in "glacial earthquakes" with readings of up to 5.1 on the Richter scale in Greenland.

These earthquakes have resulted in a tremendous amount of ice falling off Greenland into the sea. "There's an amount of fresh water melting off of Greenland now that's bigger than the whole annual flow of the Colorado River times 10," Gore says.
Al Gore on rising sea levels

If Greenland and Antarctica continue to melt, Gore says the maps of the world will need to be redrawn. Low-lying areas near southern Florida, Manhattan and the area surrounding the San Francisco Bay could end up under water, Gore warns.

In the low countries of Western Europe—the Netherlands, Belgium and Luxembourg—millions of people would need to relocate. In Beijing, 20 million people live in areas that would be flooded, and in Shanghai, the devastation would be even worse. Forty million Chinese citizens would become climate refugees.

Although Gore says he doesn't feel like Noah from the Bible, he does feel compelled to warn others about the frightening reality of rising sea levels. "If you found a message in a bottle that washed up on the beach that said, 'Life or death, deliver this message,' you would feel an obligation to do it," he says.

Many Americans don't want to listen to the warnings because this culture focuses on short-term gratification instead of the future, Gore tells Oprah. "You know the old cliché, 'Denial ain't just a river in Egypt,'" he says. "It's painful to think about. ... Actually, the older way of thinking in previous generations had more responsibility carved out for the future consequences of what we do now."
Al Gore on rising temperatures

A temperature increase of 1 degree may not seem like much on a sweltering summer day, but Gore warns that if the world's average temperatures continue to rise, there could be catastrophic consequences.

The 10 hottest years ever recorded in the Earth's atmospheric record have all occurred in the past 14 years, Gore says. In the summer of 2003, Europe suffered through a scorching heat wave that was responsible for the deaths of 35,000 people. That same year, temperatures shot up to 122 degrees in India...and that wasn't even the hottest summer on record. According to scientists, 2005 was the hottest year in history.

During the summer of 2006, Gore says many American cities out West set records of their own—some for all-time high temperatures and others for the number of consecutive days that reached 100 degrees or more. "It's not supposed to be 120 degrees in South Dakota," Gore says.

Temperature increases are taking place all over the world, including in the oceans. Gore warns that when the oceans get warmer, storms get stronger.
Al Gore on natural disasters

In August 2005, millions of Americans were left homeless by Hurricane Katrina, one of the most powerful hurricanes in recent history. Gore says people should expect more Category 4 and 5 hurricanes if the ocean waters continue to warm.

"Ocean-based storms [get] stronger because when the top layer of the water gets warmer, the wind speed in these hurricanes goes up and the moisture content goes up," Gore says.

In the last few years, many big hurricanes have blown ashore...but that's not the only natural disaster Americans have to worry about. Gore says the United States also recently set an all-time record for the number of tornadoes to touch down.

In other parts of the world, Japan set a record for the number of typhoons, and science textbooks had to be rewritten when the first ever South Atlantic hurricane hit Brazil. "[There are] all kinds of unusual's like a nature hike through the Book of Revelations," Gore says.

While warmer oceans cause flooding in some parts of the world, they cause severe droughts in others. Gore says the warmer air holds more moisture, so when there are storm conditions, more rain falls at once. Rain is also falling in different areas. In Africa, Lake Chad—once one of the world's largest lakes—completely dried up over the last few decades, Gore says.

Drought causes dry soil and vegetation, which in turn cause more wildfires. "Today, there are five large wildfires in Southern California threatening hundreds of homes and the experts are saying, 'Look, these are the driest conditions that we've ever had,'" Gore says.
Leonardo DiCaprio

Al Gore has changed the way millions view global warming, including one of Hollywood's hottest stars...Leonardo DiCaprio. Leo says Gore first introduced him to this environmental issue eight years ago. "[Al Gore] is an amazing environmental leader," Leo says. "He's a great genius of our time."

Leo was so inspired by Gore, he brought his message to The Oprah Show in October 2005 , and even began driving a hybrid car. Leo calls Gore's documentary, An Inconvenient Truth, "astounding."

"I think [An Inconvenient Truth] really blew the lid off the issue in such a major way, and I truly believe it's the obligation of every American citizen to go see this film," he says. "We are the biggest contributor to global warming in the entire world, and if we don't make a difference, we don't change our ways, a lot of things will go terribly wrong. It is one of the single most important issues facing the entire world."
Marlo Lewis, senior fellow at the Competitive Enterprise Institute

Marlo Lewis, senior fellow at the Competitive Enterprise Institute—a Washington, D.C., think tank—specializes in environmental policy and questions Gore's global warming claims. Recently, he wrote A Skeptic's Guide to an Inconvenient Truth to rebut Gore's research.

Marlo says An Inconvenient Truth makes it seem like we can reasonably expect the sea level to rise 20 feet in our lifetime or the lifetime of our children. "This is science fiction," he says.

Americans also shouldn't worry about environmental changes in Greenland or Antarctica, he says. "If you look at the actual loss of ice in Greenland and what it translates into, in sea level rise, it's about one inch over a century," he says. "Several studies show that the entire continent of Antarctica is actually gaining ice mass. That's an inconvenient fact that is nowhere mentioned in the film."

Marlo believes that Gore's film is an attempt to "scare us green." "He wants us to be very frightened of global warming," Marlo says. "The warming that we've seen over the last 30 years is constant and modest, and in all likelihood, will give us a modest amount of warming in the next century. And, therefore, it's nothing to be afraid of."
Al Gore responds to skeptics.

Though skeptics question the seriousness of global warming, Gore is unwavering. He says many of the organizations that have come out with studies questioning the effects of global warming are funded by the worst polluters, including certain oil and coal companies.

"They crank out so-called studies that are designed to make people think, 'Hey, there's no problem. Just let us keep on putting as much pollution up there as we want. Don't make us be responsible,'" he says.

For the true "expert opinion," Gore says people should take a look at a study conducted by the University of California. In this study, researchers conducted a peer review of experts' journal articles on global warming from the past 10 years.

The result? "None of them disagreed with the main consensus," Gore says. "There are some aspects of this issue where there is a continuing debate around the edges, but the central consensus is as strong as it ever gets in science."

In a special issue of Scientific American magazine, Gore says editors concluded that the debate on global warming is over. "It is real," he says. "It is happening now."
Al Gore shops at Lowe's.

You are not helpless in the fight against global warming. Gore goes inside a Lowe's Home Improvement store outside Nashville, Tennessee, to show you the five things you can buy that will help solve the climate crisis...and save you a few bucks!

  • Compact fluorescent light bulbs: These energy-efficient bulbs cost less than $4 and are produced by major corporations like GE. If every household in America switched five regular light bulbs for five fluorescent bulbs, it would be the equivalent of taking 1 million cars off the highways for a full year.
  • Outdoor solar lighting: These yard or patio lights cost less than $20, and they don't burn any electricity or produce any CO2.
  • Programmable thermostats: Though these thermostats cost from $50 to $100, they can actually cut your heating and cooling costs. Set the setting so it's a little bit cooler in the winter and warmer in the summer when you're not in the house. A difference of 2 degrees can reduce a home's CO2 emissions by up to 9 percent over the course of a year.
  • Air filters: Changing the air filters in your heating and cooling systems regularly can knock 2 percent off of your CO2 output each year.
  • Electric hot water heater blanket: Hot water heaters use a lot of energy and generate a lot of CO2. A blanket costs less than $18 and can cut your home's CO2 emissions by almost 4 1/2 percent.

Gore says that when you're shopping for major home appliances, look for the Energy Star label. "This is a signal that you're getting an environmentally efficient appliance that's going to save you money at the same time," he says.
Al Gore and Oprah

In December 2006, Gore and his wife, Tipper, were the unofficial hosts of thousands of viewing parties for the DVD of An Inconvenient Truth.

Gore says he donated 100 percent of his profits from his movie and book to a non-partisan effort to continue education on global warming.

Through education, Gore hopes that people will begin to understand the effects of global warming and take the warnings more seriously. "There were clear warnings about Hurricane Katrina—the levies might fail," he says. "And the warnings were ignored. We saw the consequences. This time, the warnings are of dangers much, much greater. [This is] the most serious crisis we've ever confronted and the consequences of ignoring these warnings would literally be unforgivable. We cannot allow a future where our children look back at this point in time and say, 'What were they thinking?'"

Learn more about the issues shaping your world.