Why Ice Ages Return Every 100,000 Years
The Long Winter
6,363 views
Around 125,000 years ago, hippos swam in the Thames where Trafalgar Square now stands. Then the northern summers weakened, the snow stopped melting, and the ice came back, on a schedule set by Earth's orbit.
CHAPTERS
00:00 — A Circle That Moves
05:43 — Hippos Under Trafalgar Square
12:14 — The Museum Keeper Who Read the Planets
20:09 — Leaning Toward the Sun
26:32 — The Wandering Pole Star
32:34 — A Letter on the Equinox
38:10 — The Snow That Stayed
43:38 — How Ice Makes More Ice
48:56 — The Ocean Holds Its Breath
55:34 — When the Sahara Turned Green
1:01:06 — Under Three Kilometres of Ice
1:09:46 — Survivors on the Move
1:18:42 — Faster Than It Came
1:27:03 — What the Trawl Net Brought Up
1:34:50 — A Line Cut in 1731
1:42:34 — Eighteen Years Too Late
1:50:22 — The Clock in Devils Hole
1:57:57 — When a Day Lasted Seventeen Hours
2:05:33 — Waiting for a Cold Summer
2:12:13 — The Weakest Beat
SOURCES (selected)
Croll, J. (1875). Climate and Time
Milankovitch, M. (1941). Kanon der Erdbestrahlung (English edition 1969)
Hays, Imbrie & Shackleton (1976). Variations in the Earth's Orbit: Pacemaker of the Ice Ages. Science
EPICA community members (2004). Eight glacial cycles from an Antarctic ice core. Nature
Laskar et al. (2004). Astronomy & Astrophysics
Lisiecki & Raymo (2005). Paleoceanography
Abe-Ouchi et al. (2013). Nature
Lambeck et al. (2014). PNAS
Winograd et al. (1992); Moseley et al. (2016). Science
Lantink et al. (2022). PNAS
Ganopolski, Winkelmann & Schellnhuber (2016). Nature
Barker et al. (2025). Science
4 Comments
Why Ice Ages Return Every 100,000 Years
The Long Winter
6,363 views
Around 125,000 years ago, hippos swam in the Thames where Trafalgar Square now stands. Then the northern summers weakened, the snow stopped melting, and the ice came back, on a schedule set by Earth's orbit.
CHAPTERS
00:00 — A Circle That Moves
05:43 — Hippos Under Trafalgar Square
12:14 — The Museum Keeper Who Read the Planets
20:09 — Leaning Toward the Sun
26:32 — The Wandering Pole Star
32:34 — A Letter on the Equinox
38:10 — The Snow That Stayed
43:38 — How Ice Makes More Ice
48:56 — The Ocean Holds Its Breath
55:34 — When the Sahara Turned Green
1:01:06 — Under Three Kilometres of Ice
1:09:46 — Survivors on the Move
1:18:42 — Faster Than It Came
1:27:03 — What the Trawl Net Brought Up
1:34:50 — A Line Cut in 1731
1:42:34 — Eighteen Years Too Late
1:50:22 — The Clock in Devils Hole
1:57:57 — When a Day Lasted Seventeen Hours
2:05:33 — Waiting for a Cold Summer
2:12:13 — The Weakest Beat
SOURCES (selected)
Croll, J. (1875). Climate and Time
Milankovitch, M. (1941). Kanon der Erdbestrahlung (English edition 1969)
Hays, Imbrie & Shackleton (1976). Variations in the Earth's Orbit: Pacemaker of the Ice Ages. Science
EPICA community members (2004). Eight glacial cycles from an Antarctic ice core. Nature
Laskar et al. (2004). Astronomy & Astrophysics
Lisiecki & Raymo (2005). Paleoceanography
Abe-Ouchi et al. (2013). Nature
Lambeck et al. (2014). PNAS
Winograd et al. (1992); Moseley et al. (2016). Science
Lantink et al. (2022). PNAS
Ganopolski, Winkelmann & Schellnhuber (2016). Nature
Barker et al. (2025). Science