09.2.2019
Settled Science? 7 New Papers Show Regional Temps Were 2-6°C Warmer Than Today During The Last Glacial!
glacial period.
Image Source: Ganyushkin et al., 2018
Between 45 and 30 thousand years ago, or during the middle of the last glacial, atmospheric CO2 levels hovered around 200 ppm – less than half of today’s concentration.
Image Source: Kohfeld and Chase, 2017
Tree remains dated to this period have been discovered 600-1000 meters atop the modern treeline in the Russian Altai mountains. With lapse rate and tectonic changes considered, this suggests surface air temperatures were between 3°C and possibly up to 5.9°C warmer than today (Ganyushkin et al., 2018) at this time.
Image Source: Ganyushkin et al., 2018
Modern sea surface temperatures of 15.5°C and 10°C have been recorded in the subpolar North Atlantic (Tobago Basin and Bonair Basin, respectively). Between and about 10 and 15 thousand years ago, temperatures reached 23°C and 17°C, respectively, which is ~7°C warmer than today). Temperatures were 2-4°C warmer than today between 20 and 30 thousand years ago (Reißig et al., 2019).
Image Source: Reißig et al., 2019
Today’s North Atlantic’s bottom-water temperatures are about 4°C. They averaged ~5°C during the last glacial, with anomalies reaching 10°C both 13 and 16 thousand years ago and about 7°C both 15 and 19 thousand years ago (Yasuhara et al., 2019).
Image Source: Yasuhara et al., 2019
Modern annual temperatures at a California lake average 18°C. Between 31 and 24 thousand years ago, temperatures averaged 22°C to 23°C, which is about 4-5°C warmer than today (Feakins et al., 2019).
Image Source: Feakins et al., 2019
The modern temperature in the subarctic North Pacific ranges beween 3 to 4°C. About 14,500 years ago, the region had warm peaks of 5 to 9°C, as well as 4 to 7°C between 18 and 20 thousand years ago (Lohmann et al., 2019).
Image Source: Lohmann et al., 2019
Sea surface temperatures near the Peruvian coast have plummeted in the last 50 years, with catfish remains in northern Peru suggesting this region was 4°C warmer than today during the Early Holocene. One reconstruction shows the region was ~2°C warmer than today about 15 to 16 thousand years ago (Salvatteci et al., 2019).
Image Source: Salvatteci et al., 2019
The “present observed temperatures” appear to be less than 24°C in the South Atlantic. This region was about 2°C warmer than today from about 10 thousand years ago to the Roman Warm Period, but it also reached similar or slightly (~1°C) warmer temperatures around 52 to 60 thousand years ago (Dauner et al., 2019).