Climate chaos: The mass extinction that reshaped life on Earth

The end-Permian mass extinction, 252 million years ago, was devastating to life on Earth. Massive volcanic eruptions unleashed 100,000 billion metric tons of carbon dioxide, triggering a severe climate crisis.

This led to extreme global warming, deoxygenated oceans, and widespread extinction. However, many plants survived, leaving fossil records that help scientists understand a dramatic 10-degree rise in global temperatures.

“While fossilized spores and pollen of plants from the Early Triassic do not provide strong evidence for a sudden and catastrophic biodiversity loss, both marine and terrestrial animals experienced the most severe mass extinction in Earth’s history,” explained Dr. Maura Brunetti of the University of Geneva.

“Life on Earth had to adjust to repeated changes in climate and the carbon cycle for several million years after the Permian-Triassic Boundary.”

Reconstructing the ancient climate

The scientists studied five geological stages on either side of the Permian-Triassic Boundary. These included the Permian Wuchiapingian and Changhsingian, the early Triassic Induan and Olenekian, and the middle Triassic Anisian.

Using maps of Earth’s ancient geography and plant fossil data, the researchers identified six major biomes and estimated local climates based on fossil distributions.

The identified biomes ranged from tropical, humid regions to seasonal temperate and desert areas.

Cold climates featured desert in the tropics and tundra at higher latitudes, while warm climates had temperate vegetation near the poles and deserts near the equator. Increased carbon dioxide levels led to warmer and wetter conditions.

Climate and ecosystem shifts after extinction

Using statistical models, the scientists compared plant fossil records with simulated biomes under different climate conditions. Their findings revealed dramatic shifts in ecosystems at the Permian-Triassic Boundary.

Before the extinction, the Permian had a colder climate. The early Triassic Induan period showed unstable conditions that scientists could not clearly classify.

This uncertainty may be due to sampling biases, poor fossil preservation, or short-term climate variations. More fossil data is needed for clarity.

Later Triassic periods saw significantly warmer conditions. The Olenekian and Anisian stabilized at temperatures 10 degrees higher than the Permian.

A hotter future

“This transition from the colder climatic state to the hotter state is marked by an increase of approximately 10⁰C in the mean global surface air temperature and an intensification of the water cycle,” said Dr. Brunetti.

“Tropical everwet and summerwet biomes emerged in the tropics, replacing predominantly desertic landscapes. Meanwhile, the warm-cool temperate biome shifted towards polar regions, leading to the complete disappearance of tundra ecosystems.”

Dr. Brunetti noted that the shift in vegetation cover can be linked to tipping mechanisms between climatic steady states, providing a potential framework for understanding the transition between Permian and Triassic.

“This framework can be used to understand tipping behavior in the climate system in response to the present-day CO2 increase. If this increase continues at the same rate, we will reach the level of emissions that caused the Permian-Triassic mass extinction in around 2,700 years — a much faster timescale than the Permian-Triassic Boundary emissions.”

Uncertainties and future research

More data and refined models are necessary for clearer conclusions. “The comparison between simulated biomes and the dataset is influenced by uncertainties, arising from paleogeographic reconstructions and the classification of fossil assemblages into biomes,” said Dr. Brunetti.

“Furthermore, our climate modeling setup relies on offline coupling between models — the vegetation model uses the final outputs of the climatic model for biome reconstruction. This could be enhanced using a dynamic vegetation model.”

The Permian-Triassic extinction reshaped life on Earth. Studying its causes and consequences may provide valuable insights into the ongoing climate crisis.

Climate lessons from past extinctions

The Permian-Triassic extinction reshaped the planet, erasing entire ecosystems and paving the way for new ones.

By studying how life responded to these changes, scientists can better predict how today’s ecosystems will react to rising temperatures and shifting climate patterns.

Understanding the past is crucial for preparing for the future. If history is any indication, life on Earth will survive – but whether human civilization can adapt as effectively remains an open question.

The study is published in the journal Frontiers in Earth Science.

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