Our planet has always seen big shifts in climate, swinging between freezing and warm periods. While scientists typically connect these changes to carbon dioxide levels, recent studies suggest it’s more complicated.
New research highlights the role of tectonic plates in driving climate changes. It appears that both the collisions and separations of these plates are crucial in managing carbon levels in our atmosphere.
Published in the journal Communications, Earth and Environment, this study explores how plate tectonics have influenced Earth’s climate over the last 540 million years.
The Carbon Cycle Explained
At the edges of colliding tectonic plates, we find chains of volcanoes known as volcanic arcs. These volcanoes release ancient carbon locked in rocks for eons. This process was once thought to be the main method for adding carbon dioxide to the atmosphere.
However, this study suggests that regions where tectonic plates pull apart, like mid-ocean ridges and continental rifts, may contribute even more significantly to global carbon cycles. The oceans play a key role by absorbing vast amounts of carbon dioxide and storing it within carbon-rich sediments on the seafloor.
Over thousands of years, these sediments can accumulate and eventually be subducted back into the Earth’s interior, releasing carbon dioxide into the atmosphere once more. This entire process, termed the “deep carbon cycle,” can be tracked using computer models to understand how tectonic activity has shifted over time.
Key Discoveries
Using advanced computer models, researchers have reconstructed how carbon has moved through the Earth and how it correlates with different climate states. During warmer periods, more carbon is released than is absorbed, leading to higher atmospheric carbon levels. Conversely, during cooler periods, the oceans efficiently absorb carbon, lowering atmospheric levels and causing the planet to cool.
One striking finding highlights the importance of deep-sea sediments. They play a critical role in managing atmospheric carbon dioxide, especially as tectonic plates shift and subduct, cycling carbon back into the Earth.
Rethinking Volcanic Arcs
The understanding of volcanic arcs has evolved. They were previously seen as major sources of atmospheric carbon, but this only became significant in the last 120 million years. This surge in emissions is largely thanks to tiny ocean organisms called planktic calcifiers. These phytoplankton convert dissolved carbon into calcite, creating carbon-rich sediments on the ocean floor.
Before their evolution roughly 200 million years ago, carbon emissions from mid-ocean ridges and continental rifts were more substantial contributors to atmospheric carbon dioxide.
A New Outlook on Climate
This research changes our understanding of how tectonic activity shapes climate. Instead of focusing solely on atmospheric carbon, it’s crucial to consider the balance of carbon emissions and how much is trapped in ocean sediments.
Such insights are vital for developing future climate models, especially as concerns over rising carbon dioxide levels grow. The interplay between Earth’s natural carbon cycle and human activity is significant for predicting future climate scenarios.
In summary, understanding these tectonic processes and their long-term effects can improve how we anticipate and respond to changes in our climate.
