Only a few thousand years ago, when CO2 levels were both stable and low (~265 ppm), the (1) Arctic had far less ice and more vegetation than it does now and (2) the massive rate of ice melt in Antarctica rendered modern melt rates negligible by comparison.
A new study (Cherezova et al., 2020) reveals that until about 6,500 years ago Bolshevik Island in the Russian High Arctic brimmed with grass, birch and willow trees, and large herbivores grazing on grass year-round. At that time sea levels were rising at rates of 7.9 mm/yr, which is more than 5 times faster than the global sea level rise trend since 1958 (~1.4 mm/yr, Frederikse et al., 2018).
Today this same High Arctic island is treeless with “very scarce vegetation.” It is locked in sea ice and mean annual temperatures only reach -13°C, which is a “similar climate to the Lateglacial.” Modern climate warming “is not observed” in either the meteorological or ice core data (Tvyordoe Lake) for this region. The ice caps are todayabout the same size as they were during thepeak of the last ice age (~20,000 years ago).
