https://nsidc.org/arcticseaicenews/charctic-interactive-sea-...

Arctic sea ice extent is currently tracking the 2010-2020 average. Nothing much is happening in terms of Arctic sea ice extent at the moment and that's been true for a while. There has been a steady decline since 1979, which is the earliest year Charctic shows. But data exists for much longer. This is unfortunately standard for climatology, they truncate many data sets starting at this time and then declare records based on that truncated data set. That's not because nobody cared about the poles before the 80s, people definitely did.

Here are some examples. In the 1990 IPCC report, we can see satellite data for the Arctic going back to ~1972 and it shows a huge rise in sea ice extent during that decade ([1], p224, figure 7.20). This data is no longer shown on modern graphs.

This 1985 report [2] is by the US Department of Energy "Office of Basic Sciences Carbon Dioxide Research Division", it covers many topics around the construction of global climate models. Figure 5.2 on page 181 shows data on sea ice extents going back to the 1920s, citing Vinnikov et al. It shows a massive fall in sea ice from the 1920s to about 1955, when it turns around and starts climbing again. This data is corroborated by news reports. In the 1920s there were reports about melting ice caps. These were the dustbowl years and the 20s-30s were very hot. But in the middle of the century that turned around and by the mid 1960s the climate had been cooling for decades. The NYT reported [3] that:

The United States and the Soviet Union are mounting large‐scale investigations to determine why the Arctic climate is becoming more frigid, why parts of the Arctic sea ice have recently become ominously thicker and whether the extent of that ice cover contributes to the onset of ice ages.

Sea ice continued to thicken and by 1975 newspapers were reporting a consensus of experts that the future had a lot more ice in it, claims made credible by the growing Arctic ice conditions [4]:

In the last decade, the Arctic ice and snow cap has expanded 12%, and for the first time this century ships making for Iceland ports have been impeded by drifting sea ice [...] Many climatologists see this as evidence that a significant shift in climate is taking place [....] No scientists are predicting a full-scale Ice Age soon, but some predict that in a few decades there might be little ice ages

So the Arctic and Antarctic have changed quite a bit in the 20th century. They grow, they shrink, and scientists know this but no longer are willing to show these old datasets because the picture they paint is not a very interesting one. It certainly would not convince anyone that climatology is the key to saving the planet from doom.

[1] https://archive.ipcc.ch/ipccreports/far/wg_I/ipcc_far_wg_I_c...

[2] https://www.osti.gov/servlets/purl/5885458

[3] https://www.nytimes.com/1970/07/18/archives/us-and-soviet-pr...

[4] https://chicagotribune.newspapers.com/search/?query=%20new%2...