The magnitude problem persists for peddlers of Climate Alarm.
During the last interglacial (LIG) 127-119k years ago atmospheric CO2 was said to be 275 ppm, and yet the global sea levels were 6-9 m higher than they are today.
The higher sea levels were due primarily to the LIG’s substantially warmer temperatures, which meant that less water could remain frozen on land as ice during these millennia.
For example, in contrast to today’s 1-2 km thick northern Greenland ice sheet, the Greenland’s northernmost latitudes were ice-free (and vegetated/forested) during the LIG warmth, a melt magnitude that is estimated to have added 300 cm (3 m) of sea level equivalent (SLE) to the globe’s sea levels (Sommers et al., 2021).
Image Source: Sommers et al., 2021
Today, in contrast, Greenland’s ice sheet covers 80% of the land mass, including 100 m and more ice thicknesses stretching across northern and southwest Greenland – regions which were ice-free during the LIG.
From 1992 to 2020, as CO2 rose from 356 to 415 ppm, the sea level rise contribution from Greenland’s ice melt amounted to a total of just 1.2 cm of SLE (Simonsen et al., 2021).
Image Source: Simonsen et al., 2021
When viewed in this larger context, a 1.2 cm SLE ice melt contribution from the Greenland ice sheet in the last 28 years doesn’t seem nearly as significant or concerning as it does when perpetuators of climate alarm refer to hundreds of billions of tons of ice lost each year.