The biggest mass extinction in the history of the world was caused by carbon dioxide. That’s the conclusion of a shocking new study published last week in Science Magazine.

According to that study - the Permian Mass Extinction - which occurred 252 million years ago - started when a group of volcanoes erupted in Siberia - sending tons upon tons of CO2 into the atmosphere.

This C02 bomb then filtered into the earth's oceans - acidifying them and making them totally incapable of supporting any ecosystem whatsoever. The result was the total annihilation of 90 percent of all life on earth.

While scientists don't think that we're at risk of any supervolcano eruptions any time soon - the fact that the Permian Mass Extinction appears to have been caused by carbon dioxide is pretty scary given the state of the earth's climate these days.

At over 400 parts per million - there is now more carbon in the atmosphere at any time in human history. In fact - the last time time there was this much carbon in the atmosphere was almost 15 million years ago!

Meanwhile - to make matters worse - as a side effect of climate change - our oceans are acidifying at a rate we haven't seen in millions of years.

It shouldn't be any surprise - then - that some scientists think we're on the cusp of the next big mass extinction - all as a result of carbon pollution from fossil fuels.

But don't tell Senate Republicans that. Some of them - like Alabama Senator Jeff Sessions - don't even believe that carbon dioxide is a pollutant. He told EPA head Gina McCarthy recently that it's just a "harmless plant food."

Luckily - not everyone takes as much money and advice from the fossil fuel industry as Senator Sessions.

All around the world these days - scientists - policymakers - and activists of all stripes are hard at work finding ways to fight back against climate change. And while some of these experts are focusing on economic solutions and others are looking at political solutions - still others are exploring natural solutions to climate change.

This is the subject of our documentary "Restoration" - which is narrated by Leonardo DiCaprio.

Check it out:

I hope you enjoyed "Restoration" and the entire series as much as we did making it. For more information on the documentary you just saw and to view all four parts of the Green World Rising series go to greenworldrising.org.