Blue Sky Studios Missed A Few Things

Earth has been in a constant temperature battle long before humanity was even an idea. Our green planet has warmed and cooled at regular intervals for millions of years, resulting in the world we see today. Ice Ages are responsible for the migration of humans, inland lakes, habitat contraction, and plant migration, among many other things. How much do you know about our planet’s chilly history?

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1. Roll Call!

Our glorious planet has gone through at least five major prolonged periods of glaciation. They’re known as the Huronian, Cryogenia, Andean-Saharan, late Paleozoic, and the Quaternary Ice Ages. The Huronian Ice Age was over 2 billion years ago, while the Quaternary Ice Age started around 2.6 million years ago.

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2. Warmer Periods

While ice ages are very long and very cold, that doesn’t mean the planet is a solid block of ice for a couple of thousand years. Interglacials are shorter, warmer periods where global temperatures rise and eventually return to the levels we see today.

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3. Homo Sapiens

Our ancient ancestors lived through multiple ice ages, adapting their tools, clothing, communication, and travel skills to work with the sub-zero temperatures. In fact, Homo sapiens was the only hominin group that survived the last glacial period, leading to the decline of the Neanderthals and Denisovans.

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4. No More Worms

North American earthworms nearly went extinct during the last glacial period, as the tremendous amount of ice wiped them out. Earthworms only survived in the unglaciated areas, which included British Columbia and the Yukon. 

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5. Acid Rain

Acid rain occurs when the sulfur dioxide from volcanic eruptions mixes with the water vapor in the atmosphere. In a time of intense volcanic activity, acid rain likely caused mass extinctions and eventually brought an end to past ice ages due to the constant weathering of cap carbonate deposits.

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6. Massive Mammals

The ice ages were home to many large animal species, the woolly mammoth, mastodon, saber-tooth cat, ground sloths, and giant beavers, to name a few. The animals’ large sizes were likely a biological reaction to the chill, as their bodies could retain more heat. 

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7. Goodbye Mammals

The rapid warming of the Earth and constant habitat shifts, combined with early humans' hunting methods, were the deadly duo that caused these giant animals to go extinct. The last ice age ended about 12,800 years ago, and these broad beasts went with it.

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8. Extinct Plants

Alongside our animal friends, there are a few plant species that we also lost after the last ice age. Most notably, the Critchfield Spruce, a tree that once spanned across eastern North America, disappeared during the deglaciation period.

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9. Average Temp

During its peak, the Last Glacial Maximum (LGM) of our most recent ice age was 46°F, or 8°C. This chilly temperature is about 13-14°F, or 7-8°C colder than our global average temperature today. Of course, polar regions were much, much colder.

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10. La Brea Tar Pits

To get a better sense of some of our animal friends long passed, look no further than the La Brea Tar Pits. Located in Los Angeles, USA, these tar pits are an active paleontological site that contains millions of fossils of plant and animal life from 10,000 years ago.

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11. The Bering Strait

The Bering Strait is a shallow body of water that connects the Pacific Ocean and the Arctic Ocean, more specifically separating the most eastern parts of Russia from Alaska. The Bering Strait actually operates as a land bridge, and is likely the cause of ancient human migration into the Americas.

NASA/GSFC/JPL/MISR-Team on Wikimedia

12. Milankovitch Cycles

The Milankovitch Cycles are long-term cyclical changes in Earth’s orbit and axis, which affect the amount of solar radiation our planet receives. These cycles likely play a large role in Earth’s history of massive climate change, including our ice ages.

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13. Panama

The Isthmus of Panama, a narrow strip of land that sits between the Caribbean Sea and the Pacific Ocean, is to blame for the beginning of our last ice age. The formation of the land blocked warm water from traveling between the Atlantic and Pacific oceans, which led to increased precipitation and snow accumulation in the northern hemisphere.

Jeff Schmaltz, MODIS Rapid Response Team, NASA/GSFC on Wikimedia

14. Peaked In High School

While our most recent cooling period was around 10 to 12 thousand years ago, the Penultimate Glacial Period was considered one of the most severe cooling periods that the Earth went through. This period lasted from around 194,000 years ago to around 135,000 years ago, meaning most of Eurasia spent around 60,000 years under ice.

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15. Rethinking Civilization

While there is no current scientific evidence, there is a hypothesis that an ancient advanced society existed around 12,000 years ago, during the last ice age. Theory goes that the civilization was destroyed by a cataclysmic event, and is typically seen as the missing piece of when humans shifted from hunter-gatherer to more complex societies.

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16. Hothouse Earth

There have been a few times in the long history of our planet where no ice existed at all. Of course, Earth’s beginnings are defined as a time of lava and molten rock, so ice definitely didn't exist then. Other “Greenhouse” periods were likely around 100 to 66 million years ago, during the late Cretaceous period, and the Eocene epoch, which was around 53 million years ago.

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17. How Much Water?

During the peak of the last ice age, it’s theorized that sea levels were 410 to 430 feet (125-130 meters) lower than they are today, thanks to the amount of water sucked up into glaciers. As humans continue to heat the Earth, however, the sea levels will likely rise 230 feet or 70 meters if we lose all of our glaciers.

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18. 10,000 Years From Now

As previously mentioned, humans have really messed with the natural order of things. Scientists believed that the next ice age was naturally expected to show up within the next 10,000 to 11,000 years, but the sharp rise in temperature means we’ve significantly delayed the natural cycle, if it even happens at all.

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19. The Worst Of The Worst

The most severe ice age likely occurred around 720 to 635 million years ago, during the Andean-Saharan Ice Age, or the Neoproterozoic Era, if you prefer to call it that. This period is labelled as a “Snowball Earth,” suggesting that the entire planet was completely covered in ice. It’s also suggested that the end of this period was responsible for the Cambrian explosion.

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20. We’re Still In One

Yes, we are still technically in an ice age, the Quaternary Ice Age to be exact. Humans have existed for over 300,000 years, but our “behavioral modernity,” as in when our brains fully developed as a species, happened about 50,000 years ago. This means that our ancestors spent 40,000 years learning to adapt to incredibly cold climates before the glacial period ended around 10,000 years ago.

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