What happens at the end of an ice age? An ice age creates a completely new landscape. Valleys are created by glaciers as they crush everything in their path, new lakes and rivers are formed were their were none. Oceans rise several hundred feet at the end of an ice age destroying all shoreline settlements and burying any historical remains under water. New deserts appear where before there was only lush vegetation. Erosion and rain change the landscape and wash away any remains. An ice age is even known to have caused earth to lose a FULL billion years of its's history! Meet snowball earth;
When a Billion Years Disappeared - In some places, the rocks below the Great Unconformity are about 1.2 billion years older than those above it. This missing chapter in Earth’s history might be linked to a fracturing supercontinent, out-of-control glaciers, and maybe the diversification of life itself.
Ice ages come and go and it appears to be the very cycles of the earth around the sun and on its axis that influence these cycles over hundreds and thousands of years, sometimes in combination with others factors that increase or decrease its effects. There are cycles of the earth that last 41,000 years (Obliquity/earth-tilt causing ice ages), 23,000 years (Axial wobble, which can make a season extreme) and 100,000 years which is the time it takes for earths orbit to go from oval to circular and back again which changes the length of the seasons. This video covers how earths cycles causes major climate changes that occur over a period of thousands of years.
The History of Climate Cycles (and the Woolly Rhino) Explained
Throughout the Pleistocene Epoch, the range of the woolly rhino grew and shrank in sync with global climate. So what caused the climate -- and the range of the woolly rhino -- to cycle back and forth between such extremes?
Screenshots of the regularly repeating variations in temperature;
Africa is one of the few lands that wouldn't flood from the rise and fall of sea levels of the ice ages or the upcoming ice melt that scientists are predicting. One of the things you should notice is that lands that people like to settle and build villages and cities, such as river deltas, get flooded first. The same would have happened at the end of the last ice age.
Here you see a whole upper continent was lush habitable land and climate change, over hundreds and thousands of years completely changed the situation. Migrations from lands of drought and famine would have cause alot of social friction (such as wars) and whatever society existed before the change would have completely fallen apart.
When the Sahara Was Green
The climate of the Sahara was completely different thousands of years ago. And we’re not talking about just a few years of extra rain. We’re talking about a climate that was so wet for so long that animals and humans alike made themselves at home in the middle of the Sahara.
Screenshot of drawings in the desert of lush grassland and animals (could be more civilizational remains lost underneath the sand as we barely scratch the surface)
More damage caused by ice age glaciers that would have wiped out any settlements in the American northwest regularly.
How 7,000 Years of Epic Floods Changed the World (w/ SciShow!)
Strange geologic landmarks in the Pacific Northwest are the lingering remains of a mystery that took nearly half a century to solve. These features turned out to be a result one of the most powerful and bizarre episodes in geologic history: this region experienced dozens of major, devastating floods over the course of more than 7,000 years.
On top of all that, on the other side of the world there is emerging evidence of a comet or asteroid impact that probably hit the glaciers leaving no evidence EXCEPT a large amount of chemical evidence spread out around the earth which is being debated for some odd reason. But it made it into PBS Eons, probably because one impact crater in Greenland was found that is possibly from that same time period. The possibility of impact on ice not leaving a crater is not discussed and the large amount of chemical evidence is only indicated at.
When the Earth Suddenly Stopped Warming - For decades, scientists have been studying the cause of the Younger Dryas, and trying to figure out if something like it could happen again. And it turns out that what caused this event is the subject of a heated debate.
At 5:18 he goes into option 3 for the younger dryas, i.e. the accumulating evidence that the earth was hit by a comet 12,900 years ago;
A new discovery from Gobekli Tepe is revealing how a comet strike in 10,950 BCE may have forced the rise of an entire civilization that forever changed history's path.
Humanity has had both a fascination and a fear of comets for all recorded history, and a recent discovery at the Gobekli Tepe in Turkey might hold the key to our fixation: the Clovis comet impact that triggered the Younger Dryas period around 11,000 BCE.
Evidence from ice cores in Greenland show that about 13,000 years ago, something drastically disrupted our climate. The change was sudden, and it wiped out the remaining great fauna on Earth at the time, including the wooly mammoth, the saber-tooth tiger, and the giant sloth.
A new analysis of samples of soil and artifacts salvaged from the original excavation has revealed a surprising finding: The Paleolithic village at Abu Hureyra was indirectly hit and destroyed by fragments of a comet that slammed into Earth about 12,800 years ago.
New Clues Revealed About Clovis People
New testing of bones and artifacts show that Clovis tools were made only during a brief, 300-year period from 13,050 to 12,750 years ago.
“It is intriguing to note that Clovis people first appears 300 years before the demise of the last of the megafauna that once roamed North America during a time of great climatic and environmental change,” he said. “The disappearance of Clovis from the archaeological record at 12,750 years ago is coincident with the extinction of mammoth and mastodon, the last of the megafauna. Perhaps Clovis weaponry was developed to hunt the last of these large beasts.”
University of California: The Big Burn
Geologist James Kennett and colleagues provide evidence for a massive biomass burning event at the Younger Dryas Boundary -
Some 13,000 years ago, a cataclysmic event occurred on Earth that was likely responsible for the collapse of the Clovis people and the extinction of megafauna such as mammoths and mastodons.
That juncture in the planet’s geologic history — marked by a distinct layer called the Younger Dryas Boundary — features many anomalies that support the theory of a cometary cloud impacting Earth. The collision triggered a massive biomass burning event, and the resulting soot, ash and dust in the global atmosphere blocked out the sun, which prevented photosynthesis — a phenomenon called impact winter.
For more than a decade, UC Santa Barbara professor emeritus James Kennett has studied elements found at the Younger Dryas Boundary (YDB). He has collaborated with scientists around the globe, providing evidence at the YDB for a platinum peak as well as for spherules, melt glass, nanodiamonds and other exotic materials that can be explained only by cosmic impact.
Kennett and his colleagues have now published new research in the Journal of Geology. In two papers, they analyze existing published scientific data from ice, glacier, lake, marine and terrestrial sediment cores, finding evidence for an extensive biomass burning episode at the YDB layer representing one the most extreme events — if not the most extreme — ever experienced by our own species, anatomically modern humans. Recent extreme climate and burn events like those in California pale by comparison, Kennett said.
The group’s theory posits that a cometary cloud — a single broken-up comet broader than Earth’s diameter — entered Earth’s atmosphere, causing impacts and aerial explosions that sparked fires around the globe. Co-author William Napier, a British astrophysicist and leading expert on cometary impacts, contributed an updated section on impact theory in one of the two papers featured in the journal.
“The ice cores are the most persuasive because they are so well dated,” explained Kennett, a professor emeritus in the Department of Earth Science. “What’s more, they provide sound geochemical results that point to a large biomass burning event precisely coinciding with the YDB layer formed when this major comet impacted Earth.”
The investigators studied byproducts of biomass burning and found a peak in ammonium. They also found other peaks in combustion aerosols such as nitrate, acetate, oxalate and formate. According to Kennett, collectively these elements reflect the largest biomass burning episode in the past 120,000 years of the Greenland ice sheet.
The scientists also examined the record of atmospheric carbon dioxide entrained in Antarctic ice, which also shows an increase in CO2 at the YDB. “With extensive biomass burning, you’d expect an increase in CO2,” Kennett explained. “We used the CO2 data to estimate that about 10 percent of the Earth’s terrestrial biomass burned during this event.” Independent calculations of soot concentrations performed by lead author Wendy Wolbach, a professor of chemistry at DePaul University, and Adrian Melott, professor emeritus at the University of Kansas, confirmed that estimate, which equals approximately 10 million square kilometers — a phenomenal area to burn in just a few days to weeks.
The primary biomass burning proxy recorded in lake, marine and terrestrial sediment cores is charcoal, which was found at the YDB in 129 lake core records around the globe. “The biomass burning was so extensive and voluminous — we have evidence of it over North America, South America, Western Europe and the western part of Asia — that it blocked out the sun, causing an impact winter, with profound effects on life on Earth, particularly large animals and humans,” Kennett said. “The impact winter itself was also part of what triggered the Younger Dryas cooling in the Northern Hemisphere.”
Other natural disasters such as floods, mudslides, drought, volcanic eruptions, earthquakes and tsunamis are also common through-out our history. Here are some extreme examples to make the point;
How Volcanoes Froze the Earth (Twice) - Over 600 million years ago, sheets of ice coated our planet on both land and sea. How did this happen? And most importantly for us, why did the planet eventually thaw again? The evidence for Snowball Earth is written on every continent today.
Seas keep appearing and disappearing constantly changing the landscape and washing away everything that was there previously or burying in under sediment or water.
That Time the Mediterranean Sea Disappeared - How could a body of water as big as the Mediterranean just...disappear? It would take decades and more than 1,000 research studies to even start to figure out the cause -- or causes -- of one of the greatest vanishing acts in Earth’s history.
Lots of rain can wash away what was there previously and deposit mud on top, as well as causing mud slides, nor to mention floods. A year of rain can cause alot of damage. Imagine 2 million years of it!
That Time It Rained for Two Million Years - At the beginning of the Triassic Period, with the continents locked together from pole-to-pole in the supercontinent of Pangea, the world is hot, flat, and very, very dry. But then 234 million years ago, the climate suddenly changed for the wetter.
Cataclysms are a normal part of Earth's history. They wipe out most life and then life is reborn, in time.
A Brief History of Geologic Time - By looking at the layers beneath our feet, geologists have been able to identify and describe crucial episodes in life’s history. These key events frame the chapters in the story of life on earth and the system we use to bind all these chapters together is the Geologic Time Scale.