Ice Age Food if We Go Into One Again
Pleistocene epoch: The last ice age
The Pleistocene epoch is a geological time period that includes the last ice age, when glaciers covered huge parts of the globe. Also called the Pleistocene era, or simply the Pleistocene, this epoch began about 2.6 million years ago and ended eleven,700 years ago, according to the International Committee on Stratigraphy.
Modern humans, or Man sapiens, evolved during the Pleistocene and spread across virtually of Earth before the period ended, co-ordinate to the University of California Museum of Paleontology. The epoch also featured water ice age giants, such every bit woolly mammoths (Mammuthus primigenius) and saber-toothed cats, many of which disappeared at the end of the Pleistocene in a major extinction event.
The Pleistocene was preceded by the Pliocene epoch and followed by the Holocene epoch, which nosotros still live in today, and is part of a larger fourth dimension period called the Quaternary menses (2.half dozen 1000000 years ago to present). The name "Pleistocene" is the Latin combination of two Greek words: "pleistos" (meaning "most") and "cene," which comes from "kainos" (meaning "new" or "recent"), according to the Collins Lexicon.
Related: Russian scientists hope to restore ice historic period steppe with 'Pleistocene Park.' Will it work?
What acquired the Pleistocene ice ages?
Scientists are still learning about how water ice ages occur, but nosotros know they are driven past a series of factors, such as fluctuating carbon dioxide levels, Globe's position in the solar organization and how much heat our planet receives from the sun, Live Science previously reported. For example, the shape of World'south orbit varies on a 96,000-year bike, and the planet is cooler when it is pulled by Jupiter'southward gravity farther from the sun.
Earth has been experiencing a tendency of cooling for nigh the past 50 million years. About iv.5 million years ago, the Isthmus of Panama land bridge formed betwixt North America and South America, which may have triggered the last water ice age. The Atlantic and Pacific oceans could no longer exchange tropical h2o, forcing warm water north and increasing atmospheric precipitation in the Northern Hemisphere, which brutal as snowfall. The snow created glaciers and ice sheets, thus deflecting sunlight and continuing Globe'due south cooling trend, according to the National Oceanic and Atmospheric Assistants's Climate.gov website.
The glaciers avant-garde during colder periods of the Pleistocene, called glacials, and retreated during warmer periods, called interglacials. Scientists have identified 4 stages, or ages, within the Pleistocene epoch: the Gelasian (2.6 million to one.8 million years ago) and Calabrian (i.viii million to 781,000 years ago), representing the lower or early Pleistocene; the Chibanian (781,000 to 126,000 years ago), representing the eye Pleistocene; and the belatedly Pleistocene (126,000 to 11,700 years ago), representing the upper or late Pleistocene, according to the International Committee on Stratigraphy.
Ice age glaciers mostly retreated and melted away equally the planet warmed afterward the Pleistocene concluded, merely some ice cover has stood the examination of fourth dimension. For example, glaciers in the Antarctic Peninsula may appointment back to the earlier Pleistocene, according to the U.S. Geological Survey.
Related: 'Concluding Water ice Area' in the Arctic may not survive climate change
How common cold was the Pleistocene?
The ice age peaked during the Last Glacial Maximum well-nigh 20,000 years agone, when glaciers covered vast swathes of Northward America, Europe, Southward America and Asia. At that time, global temperatures were nigh 11 degrees Fahrenheit (half dozen degrees Celsius) lower than they are today, according to a 2020 study published in the journal Nature.
Ice age conditions were also drier than today. Because near of the water on World's surface was ice, there was footling precipitation; rainfall was nigh half of current levels. The sea level was much lower, and the shorelines were typically much farther out because glaciation trapped water in ice sheets, co-ordinate to the American Museum of Natural History in New York Urban center.
Life during the ice age
The concluding ice age is known for hosting many large mammals chosen megafauna. Mammoths, saber-toothed cats, behemothic ground sloths and mastodons roamed Due north America during this period, according to the Florida Museum of Natural History. Simply it wasn't just giant mammals. An 11-human foot-tall (3 meters), flightless bird that weighed almost as much as a polar bear inhabited Europe during the early on Pleistocene, Live Science previously reported. Meanwhile, Megalania prisca, the largest known terrestrial cadger, lived in open forests, woodlands and other Pleistocene habitats across much of eastern Commonwealth of australia during the epoch, according to the Australian Museum in Sydney.
Although plenty of Pleistocene animals are now extinct, much of the wildlife would be familiar to humans today. For example, alongside mammoths in Alaska, there were the aforementioned brown bears (Ursus arctos), caribou (Rangifer tarandus) and wolves (Canis lupus) every bit there are today, according to the National Park Service. On the other side of the world, in Western Australia, the remains of an ancient campfire discovered in 2018 propose Ancient people held a kangaroo feast at the height of the Pleistocene ice age about 20,000 years agone. Of class, there weren't whatsoever nonavian dinosaurs, as they became extinct at the end of the Cretaceous catamenia, more than than 60 million years before the Pleistocene epoch began.
Related: Severed head of a giant xl,000-yr-onetime wolf discovered in Russia
Pleistocene extinctions
Most of the megafauna went extinct toward the cease of the Pleistocene epoch. In North America, about 38 groups of mammals disappeared, and most of those were over about 99 pounds (45 kilograms), co-ordinate to a 2020 report in the journal Proceedings of the National University of Sciences. Short-faced bears, armadillo-like Glyptotherium and helmeted muskox (Bootherium bombifrons) were amidst the extinction casualties, equally well as mastodons, saber-toothed cats and nigh mammoths.
Scientists accept debated for many decades what caused the Pleistocene extinctions. The main statement put forward is that either natural climatic change or man activity, including overhunting, primarily collection the extinctions, co-ordinate to the Sam Noble Museum at the Academy of Oklahoma. Another, more controversial theory is that the explosions acquired by the breakdown of a big comet as it entered the atmosphere 12,900 years agone led to woods fires in North America and climate change, which, in turn, played a major part in the extinctions.
Globe was warming as information technology exited the Pleistocene epoch most 11,700 years agone. The glaciers retreated, and humans started farming at the dawn of a new era: the Holocene epoch, also called the "age of man."
Additional resource
See some of the Pleistocene finds from the La Brea Tar Pits on the La Brea Tar Pits and Museum website. To larn most attempts to resurrect a Pleistocene ecosystem and bring back mammoths from extinction to combat climate change, watch this short YouTube video by BBC Reel. For a more than detailed look at Pleistocene megafauna, check out "Vanished Giants: The Lost World of the Ice Age" (University of Chicago Press, 2021).
Bibliography
Anne Mussuer, The Australian Museum, "Megalania prisca," Aug. 17, 2020. https://australian.museum/larn/australia-over-time/extinct-animals/megalania-prisca/
Cohen et al., International Commission on Stratigraphy, "The ICS International Chronostratigraphic Chart," 2022. https://stratigraphy.org/ICSchart/ChronostratChart2022-02.pdf
Collins English language Dictionary, "Definition of Pleistocene." https://www.collinsdictionary.com/lexicon/english/pleistocene
David Polly, University of California Museum of Paleontology, "The Pleistocene," Apr 30, 1994. https://ucmp.berkeley.edu/quaternary/ple.html
Florida Museum of Natural History, "The Pleistocene Epoch," Aug. 12, 2021. https://www.floridamuseum.ufl.edu/fossil-horses/time-scales/pleistocene/
Laura Geggel, Live Science, "Aboriginal People Held a Kangaroo Banquet Around a Bivouac 20,000 Years Ago," May 29, 2018. https://www.livescience.com/62685-ancient-aboriginal-kangaroo-feast.html
Megan Gannon, Live Science, "Why Do Ice Ages Happen?" Sep. i, 2019. https://www.livescience.com/what-causes-water ice-ages.html
Meltzer, D. J. "Overkill, glacial history, and the extinction of North America's Ice Age megafauna," Proceedings of the National Academy of Sciences, Volume 117, Nov. 17, 2020. https://doi.org/10.1073/pnas.2015032117
Michon Scott, National Oceanic and Atmospheric Administration (NOAA) Climate.gov, "What'south the coldest the Earth's ever been?" Feb. eighteen, 2021. https://www.climate.gov/news-features/climate-qa/whats-coldest-earths-e'er-been
Mindy Weisberger, Live Science, "Extinct 11-Foot 'Super-Ostrich' Was As Massive As a Polar Bear," June 27, 2019. https://www.livescience.com/65807-extinct-super-ostrich.html
Norris et al., American Museum of Natural History, "Plio-Pleistocene." https://research.amnh.org/paleontology/perissodactyl/concepts/deep-time/plio-pleistocene
Pamela Groves, National Park Service, "Pleistocene Megafauna in Beringia," Feb. 7, 2019. https://www.nps.gov/articles/aps-17-1-iv.htm
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Tierney et al. "Glacial cooling and climate sensitivity revisited," Nature, Volume 584, Aug. 26, 2020. https://doi.org/ten.1038/s41586-020-2617-ten
U.South. Geological Survey (USGS), "Are today'due south glaciers leftovers from the Pleistocene ice age?" https://www.usgs.gov/faqs/are-todays-glaciers-leftovers-pleistocene-ice-age
Ben Biggs contributed to this article
Source: https://www.livescience.com/40311-pleistocene-epoch.html
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