LOS ANGELES, CA (Catholic Online) - "We may have found the hottest time the world has ever had," Geologist Paul Wignall at the University of Leeds in England says.

The Permian Era was about 250 million years ago and marked the greatest die-off in Earth's history. One of the chief factors behind this hellish environment was probably catastrophic volcanic activity. Great volcanoes spewing lava and ash in the area that is now known as Siberia and occupied as 2.7 million square miles of boiling lava. These eruptions may have released gases that damaged Earth's protective ozone layer.

Following the conclusion of the Permian mass extinction came a time "called the 'dead zone,'" Wignall said. "It's this 5-million-year period where there's no recovery, where there is a very low diversity of life."

The dead zone experienced extremes of global warming. Scientists have analyzed fossils dating from 253 million to 245 million years ago, shortly before and after the mass extinction.

Researchers studied isotopes or atomic variants of oxygen within these fossils. As marine creatures form shells, bones and teeth, "they tend to use lighter isotopes of oxygen under warmer conditions," Wignall said. "You can still see this today when looking at modern-day sea creatures. The ratios of oxygen isotopes in their shells are entirely controlled by temperature."

Strange, eel-like creatures known as conodonts, known mainly by their elaborate mouthparts came from the Nanpanjiang Basin in south China, which helped reconstruct what temperatures were like around the equator at the end-Permian.

Different conodonts helped determined what temperatures were at different depths. One group dubbed the Neospathodus, lived down about 230 feet deep, while others, such as Pachycladina, Parachirognathus and Platyvillosus lived near the surface.

"We had to go through several tons of rock to look at tiny conodont fossils," Wignall said. "People always thought the end-Permian extinctions were related to temperature increases, but they never measured the temperature then in much detail before, since it involves a lot of hard work looking at these microfossils."

The research revealed the largest "case of extreme global warming, the most extreme ever seen in the last 600 million years," Wignall said. "We think the main reason for the dead zone after the end-Permian is a very hot planet, particularly in equatorial parts of the world."

It's estimated that the upper part of the ocean may have reached about 100 degrees, and sea-surface temperatures may have exceeded 104 degrees. By comparison, today's average annual sea-surface temperatures around the equator are 77 to 86 degrees.

"Photosynthesis starts to shut down at about 395 degrees, and plants often start dying at temperatures above 104 degrees," Wignall said. "This would explain why there's not much fossil record of plants at the end-Permian- for instance, there are no peat swamps forming, no coal-forming whatsoever. This was a huge, devastating extinction."

Without plants to absorb carbon dioxide, more of this heat-trapping gas would stay in the atmosphere, driving up temperatures further. "There are other ways of taking carbon dioxide out of the atmosphere, but the planet lost a key way for millions of years," Wignall said.

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