氷河期の正体｜地球の軌道のわずかな変化が、なぜ厚さ3キロの氷を生むのか

20,000 years ago, North America and the northern half of Europe were covered in several kilometers of ice, and sea levels were 121 meters lower than they are today. This ice age was caused by a slight change in the Earth's orbit. Why does a change in orbit cause such a drastic change in the Earth? This course delves into the topic at a university lecture level, covering everything from vagrant boulders and records of ocean floor and Antarctic ice to Milankovitch's calculations, the 100,000-year problem, and the next ice age. ▼ Table of Contents (Chapters) 0:00 Introduction 1:11 Chapter 1: Missing Rocks and the Ice Age 4:43 Chapter 2: Earth 20,000 Years Ago 7:56 Chapter 3: Records from the Bottom of the Sea 11:31 Chapter 4: Air in Ice 14:05 Chapter 5: Krol and Milankovitch 18:44 Chapter 6: Three Changes in Earth's Orbit 22:08 Chapter 7: The Pacemaker of the Ice Age 25:06 Chapter 8: Mechanisms that Amplify Change 27:56 Chapter 9: Sudden Cooling 30:50 Chapter 10: The 100,000-Year Mystery 35:17 Chapter 11: The Next Ice Age 37:37 Conclusion ▼ What you'll learn from this video: • Why ice ages occur due to orbital changes, even though the Earth's total solar radiation remains largely unchanged. • How we can understand past ice masses and atmospheric conditions from ocean bottom sediment and Antarctic ice. • How small changes amplify larger ones (albedo, carbon dioxide, ice sheet height). • Why the 100,000-year cycle is still unresolved. *The solar radiation and orbital curves at 65 degrees north latitude were calculated for this video based on the orbit of Laskar et al. (2004). The ice sheet extent map is an approximate schematic, and the timing of the next ice age is a model estimate. ▼ Main sources Hays, Imbrie & Shackleton, Science 1976/Lisiecki & Raymo, Paleoceanography 2005/Petit et al., Nature 1999/EPICA, Nature 2004/Lüthi et al., Nature 2008/Kawamura et al., Nature 2007/Abe-Ouchi et al., Nature 2013/Shackleton, Science 2000/Shakun et al., Nature 2012/Tierney et al., Nature 2020/Clark et al., Science 2009/Fairbanks, Nature 1989/DeConto & Pollard, Nature 2003/Dansgaard et al., Nature 1993/Bond et al., Nature 1992/Yan et al., Nature 2019/Ganopolski et al., Nature 2016 / Laskar et al., A&A 2004 Data: LR04, CO2 from Antarctic ice cores (Bereiter 2015), EPICA temperature (Jouzel 2007), NGRIP (NOAA NCEI), Mauna Loa CO2 (NOAA GML) ▼ Credits Music: 'Origami' by Scott Buckley – released under CC-BY 4.0. www.scottbuckley.com.au Map: Natural Earth (PD) Images (Wikimedia Commons): Armin Vogel (CC BY 2.0) / Nightflyer (CC BY 3.0) / Walter Siegmund (CC BY 2.5) / Raita Futo (CC BY 2.0) / Hannes Grobe (CC BY 3.0) / Robert Flogaus-Faust (CC BY 4.0) / NASA, NOAA, Portrait Photos, etc. (Public domain) ― A University for Adults Who Want to Learn ― This channel provides commentary that delves into all kinds of topics, exploring them to the deepest levels and cutting edge of their respective fields. ▶ Share what you've learned in the comments. Questions and opinions are welcome, and we'll respond to each one. ▶ Subscribe to the channel and join us in our next exploration. #IceAge #MilankovitchCycles #AdultLearning