Earth's volcanic past reveals the shocking reality of global warming

Scientists often look to nature for solutions to humanity’s most pressing challenges, and when it comes to understanding global warming, Earth’s geological history provides a long-term perspective that is both enlightening and alarming.

Throughout Earth’s history, catastrophic volcanic eruptions have periodically released vast amounts of carbon into the atmosphere and oceans. These massive carbon releases triggered rapid climate warming, leading to mass extinctions both on land and in marine ecosystems. 

Such periods of intense volcanism may have also disrupted the planet’s carbon-climate regulation systems for millions of years, leaving lasting impacts on the global environment.

Volcanic eruptions and major climate shifts 

A recent study led by environmental scientists at ETH Zurich explored how vegetation responds and evolves in the face of major climatic shifts. Moreover, the experts examined how these shifts influence Earth’s natural carbon-climate regulation system. 

The research team conducted geochemical analyses of isotopes found in ancient sediments and compared these data with a specially designed model that incorporates vegetation’s role in regulating Earth’s geological climate system. 

Climate shifts in Earth’s history

By using this model, the scientists were able to simulate how the Earth system responds to intense carbon releases from volcanic activity under different scenarios. They focused on three significant climatic shifts in geological history, including the Siberian Traps event, which caused the Permian-Triassic mass extinction about 252 million years ago.

“The Siberian Traps event released some 40,000 gigatons (Gt) of carbon over 200,000 years,” said ETH Zurich professor Taras Gerya. “The resulting increase in global average temperatures between 5–10°C caused Earth’s most severe extinction event in the geologic record.”

Plant recovery took millions of years 

The study revealed that the recovery of vegetation following such a catastrophic event could take several million years. During this extended period, Earth’s carbon-climate regulation system would have been severely weakened and inefficient, leading to prolonged climate warming. 

“The recovery of vegetation from the Siberian Traps event took several millions of years and during this time Earth’s carbon-climate regulation system would have been weak and inefficient, resulting in long-term climate warming,” explained lead author Julian Rogger, a scientist at ETH Zurich.

A critical finding of the study was that the severity of these catastrophic events was largely determined by how quickly emitted carbon could be sequestered back into Earth’s interior. This process occurs through mechanisms such as silicate mineral weathering or the production of organic carbon, which effectively remove carbon from the atmosphere. 

Shift in Earth’s climate evolution

The time required for the climate to stabilize and reach a new state of equilibrium depended significantly on how rapidly vegetation could adapt to the rising temperatures.

Some plant species managed to adapt by evolving or migrating to cooler regions. However, in many instances, the geological events were so catastrophic that plant species simply did not have enough time to migrate or adapt to the sustained increase in temperature. 

The inability of vegetation to respond quickly enough to these drastic changes left a geochemical imprint on Earth’s climate evolution that persisted for thousands, if not millions, of years.

Diminished carbon capacity in plants

The study’s findings have critical implications for today’s human-induced climate crisis. The research shows that disruptions in vegetation can prolong and intensify climate warming, as was the case in the geologic past. 

In some historical instances, it took millions of years for the climate to achieve a new stable equilibrium due to the diminished capacity of vegetation to regulate Earth’s carbon cycle.

“Today, we find ourselves in a major global bioclimatic crisis,” said senior author Loïc Pellissier, a professor of ecosystems and landscape evolution at ETH Zurich and WSL. 

“Our study demonstrates the role of a functioning vegetation to recover from abrupt climatic changes. We are currently releasing greenhouse gasses at a faster rate than any previous volcanic event. We are also the primary cause of global deforestation, which strongly reduces the ability of natural ecosystems to regulate the climate.”

Pellissier warns that the current trajectory of human activity mirrors the catastrophic disruptions of the past, but at a much faster pace. “This study, in my perspective, serves as a ‘wake-up call’ for the global community,” he concluded. 

The study is published in the journal Science.

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