Greenland’s climate changes are remarkably uncorrelated with climate model expectations and changes in atmospheric CO2.
When CO2 levels were in the mid-200s parts per million (11.7 to 4.5 thousand years ago) the Arctic and northern Greenland were 2-4°C warmer than now, ice margins were 80 km behind today’s, ice-free open water conditions prevailed, and Greenland warmed 10°C in just 60 years (Elnegaard Hansen et al., 2022)
Image Source: Elnegaard Hansen et al., 2022
In the last two decades, as atmospheric CO2 has increased by 25 ppm, Greenland warming “is not evident” (Matsumura et al., 2022). Instead, temperature stations document cooling trends.
Image Source: Matsumura et al., 2022
Past interglacial CO2 levels of only 280 ppm were associated with a “nearly ice free” Greenland and the presence of flora and fauna in subarctic terrestrial environments 1000 km northwards of where they can survive today, implying “at least 5°C higher temperatures” (Bennike and Böcher, 2021). Summer sea water temperatures were as much as “7-8°C higher than at present”.
Image Source: Bennike and Böcher, 2021
The assumption that Greenland’s climate (and thus ice sheet melt and associated sea level rise) can be linked to changes in atmospheric CO2 is contradicted by paleoclimate evidence and even modern instrumental temperature records.