Scientists Unveil Why Earth Stayed a Fiery Wasteland for Millions of Years

Approximately 252 million years ago, our planet faced an unparalleled biological crisis, wiping out the majority of living organisms. This event, called the Permian–Triassic mass extinction or the Great Dying, stands as the deadliest extinction episode in Earth’s history. It ended the Paleozoic Era and annihilated around 94% of ocean species along with nearly 70% of land vertebrate groups.

Crucial tropical forests, which played a vital role in managing Earth's carbon balance, also experienced severe devastation. A recent research offers new insights into the reasons behind the planet’s sustained “hothouse” climate for millions of years after this mass extinction.

Volcanic Fury: The Catalyst Behind the Crisis

The primary cause of this extinction was an enormous volcanic eruption in present-day Siberia, known as the Siberian Traps. This cataclysm unleashed vast flows of lava and carbon dioxide into the atmosphere, triggering rapid global warming. Surface temperatures surged by roughly 6°C to 10°C, creating conditions too extreme for many species to endure, leading to massive die-offs. The spike in carbon dioxide generated a super greenhouse effect, maintaining the planet's elevated warmth.

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Unlike typical volcanic climate disruptions that normalize within 100,000 to 1,000,000 years, Earth’s temperatures remained elevated for nearly five million years after this event. What caused this unusually prolonged greenhouse phase?

Decimated Forests: The Missing Piece

A significant discovery centers on the impact of the devastation to Earth’s tropical forests, which once played a fundamental role in moderating atmospheric carbon. These forests, abundant with peat bogs and thick flora, acted as major carbon sinks that helped keep the climate steady. However, the volcanic activity annihilated these ecosystems. Rapid temperature increases made survival impossible for many tropical and subtropical plants, especially rainforests. Fossil records reveal a complete disappearance of these lush habitats, creating a geological “coal gap” indicating a marked drop in organic carbon intake.

The disappearance of these forests was critical. Vegetation plays an essential part in sequestering carbon dioxide by converting it into organic matter. The loss of these natural carbon absorbers severely weakened the organic carbon cycle, stalling the planet’s recovery from extreme heat and prolonging its greenhouse state.

Gradual Renewal: The Return of Plant Life

In the aftermath, Earth’s environment began a slow recovery, though stability was a distant goal. According to the study, small, low-lying plants such as lycopods became dominant. These plants were modest in size, growing only between 2 to 20 centimeters tall.

While these pioneer species repopulated the land, their carbon absorption was far less effective than the forests they replaced. Over around five million years, larger plants gradually re-emerged, but their carbon regulation capacity remained inferior compared to the previous dense forests.

Scientists utilized a newly designed carbon cycle simulation called SCION to reveal that the persistent super greenhouse state was a consequence of lower primary productivity following ecosystem collapse. Earth's climate only began to stabilize once plants grew back and resumed capturing atmospheric carbon.