New Study: Antarctic Sea Ice Has Been Increasing Since The 1970s…Due To Internal Decadal Variability

“Since the late 1970s, Antarctic sea ice area (SIA) has slowly increased, despite significant global warming. The increase in Antarctic SIA occurred largely between 2000 and 2014.” – Bonan et al., 2024

Scientists attribute the long-term (1979-2022) expanding Antarctic sea ice trend, as well as the abrupt decline in sea ice extent from 2016 to 2019, to natural factors such as:

a) decadal variability

b) internal climate variability

c) intrinsic variability of the Southern Annular Mode (SAM)

d) El Niño-Southern Oscillation (ENSO)

e) Indian Ocean Dipole (IOD)

f) ocean preconditioning

g) weakened circumpolar westerlies

h) zonal atmospheric wave structures

i) surface wind variability

j) Pacific decadal variability

k) Atlantic multi-decadal variability

The authors acknowledge that a “unified understanding of how each process manifests spatially and temporally in the observational record is lacking.”

On the other hand, anthropogenic CO2 emissions are not considered as a contributing factor in 45 years of Antarctic sea ice expansion or decline.

Image Source: Bonan et al., 2024