From 80,000 to 12,000 years ago, when CO2 concentrations lingered near or below 200 ppm, many new or recent studies suggest that when directly comparing region to region, it was as much as 6°C warmer than today even during this ice age period. This has prompted some scientists to “exclude atmospheric pCO2 as a direct driver of SST [sea surface temperature] variations”.
Here is a short list of some of the regions as warm or warmer than today during the last ice age.
Southern Ocean: 22,000 years ago temperatures peaked at 13.6°C (and from 35,000 to 30,000 years ago temperatures ranged from 12-13°C) versus 8.5°C today, and there were “higher SST during the 40-24 kyrs period than during the Holocene” (Civel-Mazens et al., 2021).
Southern Ocean: 20,000 years ago and 85,000 to 70,000 years ago indicate “SST estimates of ~4°C which are ~2°C higher than the modern regional SST of ~2°C” (Ghadi et al., 2020).
South Atlantic: 70,000 to 35,000 years ago it was 1-5°C warmer than today, “prompting us to exclude atmospheric pCO2 as a direct driver of SST variations in the southern WTA [Western Tropical Atlantic]” (Hou et al., 2020).
Southern Africa: 26,000 to 19,000 years ago (180 ppm CO2) summer temperatures were “3-4°C higher than present” (Kraaij et al., 2020).
South Atlantic: 70,000 to 50,000 years ago as warm or warmer than today (Dauner et al., 2019).
Europe: 80,000 to 70,000 years ago it was 2-3°C warmer, as “both summer (ca. 19°C) and winter (2-4°C) temperatures above present day values (ca. 16°C and ca. 1°C for July and January, respectively)” (Ilyashuk et al., 2020).
North Atlantic: 28,000 to 23,000 years ago (Tobago Basin) and 20,000 to 12,000 years ago (Bonaire Basin) SSTs were respectively 2.5 to 6°C “warmer than modern conditions” (ReiBig et al., 2019).
North Pacific: ~35,000 to 18,000 years ago temperatures ranged between 10 and 16°C versus 9.1°C today (Max et al., 2020).
California: 31,000 to 24,000 years ago temperatures reached 22-23°C versus 18°C today (Feakins et al., 2019).
Russia: 60,000 to 54,000 years ago and it was “about 3°C warmer than today” and 31,000 years ago temperatures were “5.9?” degrees C warmer than today (Ganyushkin et al., 2018).