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Around 700 million years ago, enormous ancient glaciers gave life on Earth an evolutionary boost. Find out how in this 1-minute video, and read more below. Glaciers helped life evolve For billions of years, the moving sheets of ice we call glaciers have helped form our landscapes. And new research suggests they might also have helped form us. On Februrary 25, 2025, a team of researchers said that 700 million years ago, during one of our planet’s frigid Snowball Earth periods, enormous glaciers carved through our planet’s crust, drawing up minerals previously locked beneath the ice. And when the glaciers eventually melted, these minerals flooded Earth’s oceans, creating conditions that allowed life on our planet to surge in complexity. The researchers published their study in the peer-reviewed journal Geology on February 25, 2025. A hiker overlooks the Aletsch Glacier, the largest glacier in the Alps. Image via Robert J. Heath/ Wikimedia Commons (CC BY 2.0). The 2025 EarthSky lunar calendar makes a great gift. Get yours today! Glaciers: Nature’s bulldozers Also known as rivers of ice, glaciers are dense ice bodies that move downhill under their own weight. They form when many layers of snowfall compress each other, squeezing out any pockets of air and forming dense ice crystals. This process means that glacial ice is technically a form of metamorphic rock! But it flows downhill like slow-moving water, shaped by the land while also shaping the land itself. Glaciers have the power to bulldoze through forests with ease, and they carve out distinctive U-shaped valleys as they slide downhill. Currently, glaciers cover about 10% of Earth’s surface and hold around 68% of our freshwater. That includes the great glacial ice sheets at the poles. But scientists think that around 700 million years ago, these ice sheets covered the entire globe. This was during one of the hypothesized Snowball Earth periods, when glaciers up to 1km thick spread from pole to pole, likely due to a drop in atmospheric carbon dioxide. The researchers compared the chemical makeup of sedimentary rocks dating to before and after this glacial period. And they concluded that these enormous glaciers must have scraped deep into Earth’s crust as they moved, picking up masses of sediment and minerals. Artist’s concept of a Snowball Earth, when our planet’s surface was completely covered in ice and snow. Image via NASA/ University of Washington. Unlocking the Earth’s potential Within a few tens of millions of years, carbon dioxide levels increased to the point at which the greenhouse effect started to warm Earth out of its ice age. And as the glaciers melted, these minerals – which had previously been locked below masses of ice – were released. Lead author Chris Kirkland of Curtin University explained: When these giant ice sheets melted, they triggered enormous floods that flushed minerals and their chemicals, including uranium, into the oceans. This influx of elements changed ocean chemistry, at a time when more complex life was starting to evolve. At this time, life on Earth was very simple, and mostly – if not entirely – confined to the oceans. And it seems that this cycling of key minerals into the oceans might have given life an evolutionary boost. Kirkland said: We see different forms of life, more complex life, developing after this period of time. This wasn’t the first time in Earth’s history that widespread glaciers melted into the oceans. So you might question: why did an evolutionary explosion occur after this ice age in particular? One reason could be that it coincided with the Neoproterozoic oxygenation event, which saw a huge increase in oxygen in Earth’s atmosphere and oceans. Scientists believe this increased availability of oxygen could have contributed to the sudden development of complex life in this period, perhaps in tandem with the influx of minerals into the ocean. The mountain in the distance is Aoraki/ Mount Cook, the tallest peak in New Zealand. Long ago, the glacier running down the mountain carved out this now-verdant valley (the Hooker Valley). Image via Will Triggs. An interconnected, ever-changing world To Kirkland, the study’s findings are a testament to the interconnectedness of Earth’s natural processes. He said: This study highlights how Earth’s land, oceans, atmosphere and climate are intimately connected; where even ancient glacial activity set off chemical chain reactions that reshaped the planet. And this is especially important, Kirkland suggested, in light of our currently changing climate. He explained: This research is a stark reminder that while Earth itself will endure, the conditions that make it habitable can change dramatically. These ancient climate shifts demonstrate that environmental changes, whether natural or human-driven, have profound and lasting impacts. Bottom line: A new study says that glaciers covering our planet during a Snowball Earth period likely helped give life an evolutionary boost. Source: The Neoproterozoic glacial broom Via Curtin University Read more: What drove Snowball Earth? A drop in a greenhouse gas Read more: Salt glaciers on Mercury could harbor habitable nichesThe post Enormous glaciers on Snowball Earth helped life evolve first appeared on EarthSky.

A new study says that glaciers covering our planet during a Snowball Earth period likely helped give life an evolutionary boost. The post Enormous glaciers on Snowball Earth helped life evolve first appeared on EarthSky.