42,000 Years Ago A Massive Geomagnetic Shift Plunged A Warm Earth Into An Ice Age…But CO₂ Didn’t Budge
By Kenneth Richard on 22. April 2021
A groundbreaking new study in Science suggests warm interglacial-like conditions (surface temperatures within 1°C of today’s) persisted from 54 to 42,000 years ago even though CO₂ levels idled around 200 ppm at that time. A sudden geomagnetic shift that intensified galactic cosmic rays and cloud formation and reduced ozone levels ~42,000 years ago resulted in global-scale cooling, rapid glacier advance, disappearing water sources (lakes), plummeting sea levels, and a catastrophic peak in large animal extinctions.
In the 20 thousand years between about 55 and 35 thousand years ago, the agreed-upon paleoclimate COâ‚‚ reconstructions suggest concentrations hovered around 200 ±10 ppm (Kohfeld and Chase, 2017). It was during this phase, however, that a 33-author new study (Olsen et al., 2021) suggests abrupt and dramatic changes in the Earth’s magnetic field (for example, a “10-fold decrease in the cosmic ray cut-off rigidityâ€) about 42,000 years ago “drove synchronous global climate†from interglacial-like conditions (with surface temperatures within 1 to 1.5°C of today’s 54 to 42 ka) to a fully glacierized state.
https://notrickszone.com/2021/04/22/42000-years-ago-a-massive-geomagnetic-shift-plunged-a-warm-earth-into-an-ice-age-but-co%e2%82%82-didnt-budge/
