What's worse than global warming? Scientists find a massive reservoir of CO2 under the U.S. that could DWARF all human emissions

Humans would be nothing in comparison to such a cataclysm.

If you think the neighbor's SUV is killing us all, wait until you hear about this. A study published by British scientists just announced the discovery of a lake of molten carbon beneath the Earth's surface, spanning much of the western United States. And if just 1 percent of that carbon were released into the atmosphere, we would be instantly doomed to extinction.

LOS ANGELES, CA (California Network) -- Global warming is a major threat to humanity because it threatens to kill critical species of plants, animals, and fish, and it will shift weather patterns and agricultural lands causing social disruption. Sea levels will rise destroying the very cities that billions of people call home.

However, global warming has a much meaner, bigger brother and he's ravaged the Earth before. It's certain it will happen again.

About 250 million years ago, volcanic eruptions released so much CO2 into the atmosphere it caused the oceans to acidify which killed 90 percent of the life on Earth.

Scientists have always known such a scenario could occur again in the future. Although there are no signs such an event is imminent, a repeat is likely at some point. Scientists have pointed to the Yellowstone supervolcano as one possible scenario. The supervolcano, which is active, covers a large portion of Wyoming and is expected to erupt again someday in the next few hundred thousand years.

When it does, it will tap into the reservoir of molten carbon beneath the surface. The result will be just as catastrophic as it has been in the past, and it could result in another mass extinction. In fact, the release of just 1 percent of the carbon stored in the molten reservoir would be enough to doom the planet.

Scientists estimate that releasing one percent of the carbon stored in the reservoir would be the equivalent to burning 2.3 trillion barrels of oil.

The study was performed by geologists at the Royal Holloway University in London. Researchers used a network of 583 sensors in the Earth's crust to monitor seismic activity. These vibrations reveal information about what is deep under the Earth's surface.

The carbon reservoir is 217 miles deep in the upper mantle, much too far for anyone to drill. But it could come to the surface in a volcanic eruption.

The study is significant because it challenges what we know about the quantity of carbon deep within the Earth. It also suggests that natural sources of carbon could play a larger role in Earth's climate than previously assumed.

However, there remains solid evidence that the present case of global warming seen by scientists around the world is man-made. Natural carbon and carbon released by human activity have different isotopes which allow scientists to tell them apart. Human released carbon is still in the minority of all carbon on Earth, but the planet naturally balances its CO2 over time. Meanwhile, human added CO2 eventually overwhelms the natural processes that keep the climate stable.

But we could burn all the carbon on Earth and nature could still dwarf our activity with a single cataclysmic event.  Thankfully nothing like this is expected with our lifetime.