by K. Richard, Oct 24, 2022 in NoTricksZone
The Earth was still in ice age conditions 14,700 to 12,900 years ago, or during the “Bolling interstadial.” CO2 hovered near 230 ppm at that time, and yet “continental Europe was a few degrees warmer than present” (Toth et al., 2022).
In recent years there have been multiple studies detailing a European climate that was as warm or warmer than today during the late Pleistocene ice age.
The latest study, Toth et al., 2022, uses chironomid proxy evidence to reconstruct summer temperatures at a lake site in the Eastern Carpathians.
These authors report that “continental Europe was a few degrees warmer than present during the Bolling interstadial,” and there were slightly (0.5°C) warmer-than-today periods (e.g., ~16,300 years ago) at the study site. The warming events were both pronounced (5°C) and abrupt.
by Anthony Watts, March 15, 2019 in WUWT
Over the last 540 million years, the Earth has weathered three major ice ages — periods during which global temperatures plummeted, producing extensive ice sheets and glaciers that have stretched beyond the polar caps.
Now scientists at MIT, the University of California at Santa Barbara, and the University of California at Berkeley have identified the likely trigger for these ice ages.
In a study published in Science, the team reports that each of the last three major ice ages were preceded by tropical “arc-continent collisions” — tectonic pileups that occurred near the Earth’s equator, in which oceanic plates rode up over continental plates, exposing tens of thousands of kilometers of oceanic rock to a tropical environment.
The scientists say that the heat and humidity of the tropics likely triggered a chemical reaction between the rocks and the atmosphere. Specifically, the rocks’ calcium and magnesium reacted with atmospheric carbon dioxide, pulling the gas out of the atmosphere and permanently sequestering it in the form of carbonates such as limestone.
Over time, the researchers say, this weathering process, occurring over millions of square kilometers, could pull enough carbon dioxide out of the atmosphere to cool temperatures globally and ultimately set off an ice age.
by W.J. Davis et al., January 8, 2018 in Climate
We report a previously-unexplored natural temperature cycle recorded in ice cores from Antarctica—the Antarctic Centennial Oscillation (ACO)—that has oscillated for at least the last 226 millennia. Here we document the properties of the ACO and provide an initial assessment of its role in global climate.
See also here