Study location
Study location
Also, today's sea surface temperatures are at least 4°C colder than they were just a few thousand years ago, when the Arctic was sea-ice free for all but a couple of months a year.

Three new studies expose the lie that today's temperatures are the warmest on record.

For years scientists have been using biomarker evidence to reconstruct Arctic sea ice history. According to three new studies, modern (20th-21st century) Arctic sea ice is now at its greatest extent since the Holocene began.

Arctic was "nearly ice free throughout the year"

Scientists (Wu et al., 2020) have determined that from about 14,000 to 8,000 years ago, when CO2 lingered near 250 ppm, the Beaufort Sea (Arctic) was "nearly ice free throughout the year." Not only was it nearly ice free, it was ~4°C warmer than today in winter.

With CO2 at ~400 ppm, this region is 70-100% ice-covered for all but 1-2 summer months in the modern era.

Glaciers had retreated many km (miles) from their modern positions

Another new study (Allaart et al., 2020) concludes that from around 10,000 to 5,000 years ago, Arctic Svalbard (Wijdefjorden) glaciers had retreated many km further back than their modern positions. And the smaller ice caps had "disappeared" from the region.

Today's sea surface temperatures are at least 4°C colder than just a few thousand years ago

A third study involving a site northeast of Svalbard (Brice et al., 2020) reveals that today's sea surface temperatures of "less than 0°C" are at least 4°C colder than they were just a few thousand years ago, when the Arctic was sea-ice free for all but "a couple of months" every year.

See entire comprehensive article. Thanks to Stephen Bird for this link.