“Where’s the sea ice?” Right where it’s been for most of the Holocene.

by D. Middleton, Oct 30, 2020 in WUWT

This is sort of a sequel yesterday’s post: Where’s the sea ice? 3 reasons the Arctic freeze is unseasonably late and why it matters.

What a difference a day can make! Looks like it’s starting to crust over:

Figure 0. Daily sea ice extent map, October 29, 2020. (NSIDC)

Two key takeaways:

  1. Maximum Holocene sea ice extent occurred within the past 500-1,000 years at every location.
  2. The current sea ice extent is higher at all of the locations than over 50% to 85% of the Holocene.

While this doesn’t tell us what the sea ice extent was in million km2, it does tell us that the modern sea ice extent is larger than it was over most of the Holocene Epoch. It also tells us that the areas of currently seasonal sea ice extent have been seasonal or reduced over most of the past 5,000 years and ice-free or nearly ice-free over the prior 3,000 years or so. Here’s is the Kinnard graph plotted at the same horizontal scale as the Stein cross section: