Three More New Temperature Reconstructions Document A Warmer Medieval Period

by K. Richard, Apr 11, 2024 in NoTricksZone


he North Atlantic, the Pacific Northwest (USA), and northern Finland were all warmer than today between 1000 and 2000 years ago.

Today’s (2000 CE) July air temperatures in the Azores – archipelago islands in the middle North Atlantic, ~1400 km west of Portugal – are visually shown to average about 10 to 11°C in a newly published reconstruction (Raposeiro et al., 2024).

This average air temperature is about 1 to 2°C warmer than this location’s Little Ice Age climate, or the coldest period (~9.1°C from 1750-1800) of the last 2000 years. However, the Medieval Climate Anomaly (MCA) had temperatures reaching into the 13-15°C range, which is 3-4°C warmer than modern.

 

A temperature reconstruction from a lake in the USA’s Pacific Northwest (Baig, 2024) indicates glacial temperatures were only 1.0 to 1.6°C colder than the modern temperature, 12.2°C. Temperatures reached 13.7°C, or 1.5°C warmer than today, ~2500 years ago, and then fluctuated between 12.6 and 12.2°C from 1900 years ago until today, a period encompassing both the Medieval Warm Period and Little Ice Age.

Another lake sediment temperature reconstruction using branched glycerol dialkyl glycerol tetraethers (brGDGTs) from northern Finland (Otiniano et al., 2024) suggests the modern temperature (represented as the blue diamond) is among the coldest of the last ~8000 years. Temperatures were much warmer than modern about 1200 to 1500 years ago, and throughout the period from 7000 to 3000 years ago.