11/12/2014 02:45 pm ET Updated Nov 02, 2015

Leonardo Dicaprio: Let's Not Wait Until We Pass More Tipping Points

Around 250 million years ago most life was extinguished from our planet in a cataclysmic extinction event. Today, it could happen again.

That's the story Leonard DiCaprio tells in Last Hours, another installment of a four-part climate change documentary series directed by Leila Conners, the director of the 11th Hour film.

"Consider this," DiCaprio states at the start of the film, "Nearly all life on Earth could go extinct because of manmade climate change."

The film then takes us back to the Permian Mass Extinction 250 million years ago, an extinction event that wiped out 95% of all life on the planet. Scientists, many of whom appear in the film, are just beginning to understand what caused the Permian extinction, and it's very bad news: that wipeout of life on Earth was caused by rapid global warming.

As the film explains, science shows that massive volcanic eruptions near Siberia released enormous amounts of greenhouse gasses, sending the planet into a warming spiral. As temperatures increased, more potent greenhouse gasses like methane that had been locked away in ice under the sea for hundreds of millions of years melted and bubbled up into the air as well, pushing us past a tipping point into irreversible and catastrophic global warming.

Last Hours argues this may be happening again.

Modern society's addiction to burning fossil fuels is releasing large amounts of greenhouse gasses into the atmosphere in much the same way as were released during the volcanic eruptions of the Permian extinction. These gasses during the Permian then warmed the oceans, leading to releases of methane that spiked global warming.

Dr. Michael Benton with the University of Bristol explains in the film, "Looking at these ancient events shows us times of global warming and the atmosphere doesn't care whether the carbon dioxide comes from human activity or from a volcano. It has the same end effect."

Climate change is too often talked about in terms of dollars and cents. But as Last Hours argues, it must be talked about in terms of human survival. The film paints an alarming picture of the future if humans don't respond by reducing carbon emissions today.

In a call to action at the end of the film, DiCaprio states, "The world community must come together, step forward, and take decisive action." He goes on to call for "the largest movement in human history" to respond to climate change.

"It could mean our very survival," DiCaprio says.

Last Hours is a warning that tells us all just how high the stakes are on a planet with rapidly increasing temperatures.