A team of scientists from the University of Leeds analyzed why Earth has predominantly existed in a greenhouse state without ice caps and why the current conditions are so uncommon. Their study reveals that Earth's current ice-covered state is an anomaly resulting from a rare convergence of events.
Several theories have been suggested to explain previous cold periods in Earth's history, including reduced volcanic CO2 emissions, increased carbon storage by forests, and chemical reactions between CO2 and specific rock types. This study marks the first time all these cooling mechanisms have been examined together using an advanced 3D Earth Evolution Model, developed at the University of Leeds and made possible by recent computational advancements.
The researchers concluded that no single factor is responsible for global cooling. Instead, an ice-covered Earth requires multiple contributing processes acting in unison. Their findings, published on February 14, 2025, in Science Advances, provide insights that may resolve debates in the Earth Science community about the origins of icehouse periods.
Dr. Andrew Meredith, the study's lead author, conducted the research while at the University of Leeds' School of Earth and Environment. He explained that Earth's current ice-covered state results from a fortuitous combination of exceptionally low global volcanic activity and widely dispersed continents with substantial mountain ranges. These conditions facilitate increased global rainfall, accelerating carbon removal from the atmosphere.
"The critical takeaway here is that Earth's natural climate regulation mechanisms appear to favor a warm, high-CO2 environment rather than the low-CO2, partially glaciated conditions we experience today," Meredith said. "This general tendency towards warmth has likely prevented extreme 'snowball Earth' global glaciations, ensuring life could continue to evolve."
Professor Benjamin Mills, a co-author from the University of Leeds' School of Earth and Environment, highlighted the study's relevance to contemporary climate concerns.
"One important message is that we cannot assume the Earth will naturally return to a cold state like the pre-industrial era," Mills stated. "While Earth's history leans towards a warm climate, our modern society depends on the current ice-covered state. We must take significant steps to preserve it and avoid assuming that cooling will occur automatically if we halt excessive warming. Over geological time, Earth favors warmth, but our civilization does not."
Research Report:Phanerozoic icehouse climates as the result of multiple solid-Earth cooling mechanisms
Related Links
University of Leeds
Beyond the Ice Age
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