Breaking News:Snowball Earth: Ancient Scottish rocks challenge the ‘Snowball Earth’ theory and reshape our view of early climate– What Just Happened

Researchers at the University of Southampton have revealed compelling evidence that Earth’s climate remained to fluctuate even during its most severe ice age, known as Snowball Earth. This frigid duration, which happened during the Cryogenian between 720 and 635 million years ago, was long thought to have generated a static, frozen world where glaciers went beyond to the tropics and oceans were sealed beneath the thick ice. Scientists assumed that such situations suppressed short-term climate shifts, leaving the planet in a near-constant deep freeze.

Climate Cycles Preserved in Ancient Rocks

Recent research, published in Earth and Planetary Science Letters, challenges this perspective. Finely layered sedimentary rocks named varves from the Garvellach Islands off Scotland’s west coast disclose patterns that are similar to modern climate cycles, from yearly seasons to solar oscillations and even El Niño–like spectacles.

Thomas Gernon, Professor of Earth and Planetary Science at Southampton, remarked: “These rocks preserve the full suite of climate rhythms we know from today, annual seasons, solar cycles, and interannual oscillations – all operating during a Snowball Earth. That’s jaw-dropping. It tells us the climate system has an innate tendency to oscillate, even under extreme conditions, if given the slightest opportunity.”
Scientists evaluated 2,600 separate layers within the Port Askaig Formation, each featuring one year of sediment deposit. Lead author Dr. Chloe Griffin stated: “These rocks are extraordinary. They act like a natural data logger, recording year-by-year changes in climate during one of the coldest periods in Earth’s history. Until now, we didn’t know whether climate variability at these timescales could exist during Snowball Earth, because no one had found a record like this from within the glaciation itself.”

How the Oscillations Occurred

Analysis suggests that these layers developed through seasonal freezing and thawing in quiet, deep, calm waters beneath the ice. Statistical examination disclosed frequent cycles lasting years to decades. Dr. Griffin cited: “Some of these closely resemble modern climate patterns, such as El Niño-like oscillations and solar cycles.”

Professor Gernon further said: “Our results suggest that this kind of climate variability was the exception, rather than the rule. The background state of Snowball Earth was extremely cold and stable. What we’re seeing here is probably a short-lived disturbance, lasting thousands of years, against the backdrop of an otherwise deeply frozen planet.”
Climate simulations led by Dr. Minmin Fu stated that even a small fraction of ice-free ocean, almost 15 percent, could restore interactions between ocean and atmosphere, producing the observed oscillations. These findings indicate that the Snowball Earth is likely to experience temporary “slushball” or “waterbelt” states with patches of open ocean.

Implications for Life and Earth’s History

Dr. Elias Rugen highlighted: “These deposits are some of the best-preserved Snowball Earth rocks anywhere in the world. Through them, you’re able to read the climate history of a frozen planet, in this case, one year at a time.”

Professor Gernon stated: “This work helps us understand how resilient, and how sensitive, the climate system really is. It shows that even in the most extreme conditions Earth has ever seen, the system could be kicked into motion. That has profound implications for how planets respond to major disturbances, including our own in the future.”

Rather than a completely frozen globe, Earth during the Cryogenian may have had patches of habitable, ice-free water, offering refuges for early multicellular life and helping create the stage for the later explosion of complex ecosystems.

FAQs:

Q1. What is Snowball Earth?
Snowball Earth refers to a period during the Cryogenian when the planet was almost entirely frozen. Ice sheets extended from the poles to the tropics, creating extreme global cold.

Q2. When did Snowball Earth occur?
It occurred between around 720 and 635 million years ago. This period included two major glaciations: Sturtian and Marinoan.