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by revelio 1149 days ago
Antarctic sea ice extent is currently at the same level it was at this time of year in 1980, actually a little higher. Use Charctic to see for yourself:

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...

2 comments

We have reliable measurements of Arctic snow cover that date back to the late 1960s when satellite observations of the Earth's surface began. The earliest satellite used for snow cover monitoring was the Television Infrared Observation Satellite (TIROS) series, which was launched by the United States in 1960.

In the early 1970s, the National Oceanic and Atmospheric Administration (NOAA) launched the Advanced Very High Resolution Radiometer (AVHRR) sensor, which provided more detailed and accurate measurements of snow cover extent and duration in the Arctic.

The extent of Arctic snow cover has varied considerably from year to year, but in general, there has been a decreasing trend in snow cover extent and duration since the late 1960s. According to data from the National Snow and Ice Data Center (NSIDC), the Arctic snow cover extent has decreased at a rate of approximately 4% per decade since the late 1960s.

In recent years, there have been some variations in snow cover extent, with some years showing slightly more snow cover than others. However, the overall trend has been towards less snow cover and a shorter snow cover season.

The decrease in Arctic snow cover is thought to be due to a combination of factors, including rising temperatures, changes in precipitation patterns, and changes in the Arctic's sea ice cover. The loss of snow cover has significant impacts on the Arctic ecosystem and can contribute to further warming and changes in the region.

[0] ChatGPT

The glaciers all around the world are melting. Polar bears are drowning. While world is 1-1.5C warmer, in polar areas it's 5C and more.

There were many papers claiming that smoking doesn't cause any harm. 97% of scientists agree that climate change/crisis is human made and bad. The scientific consensus is what matters.

As a point of order, chatgpt is not a citable source. It relies on underlying sources and you can ask chatgpt to identify it’s sources for a specific response in a follow up question.
AVHRR started collecting data in the early 1980s, not the early 70s. ChatGPT is hallucinating again. I guess this is the scenario AI ethics people feared - the internet being clogged up by AI generated misinformation. If you want to take part in this debate do you own research and cite actual data.

Polar bears are doing fine, by the way.

https://polarbearscience.com/2023/02/23/published-field-stud...

It seems that AVHRR was launched in 1978 [0], with fairly continuous global coverage since June 1979 [1].

So it was not in early 1970s, it was in the late 1970s, and it was not in early 1980s. You both were pretty close.

> Polar bears are doing fine, by the way.

Good to hear. For now at least. If true.

"In 2004, biologists discovered four drowned polar bears in the Beaufort Sea. Never before observed, biologists attributed the drowning to a combination of retreating ice and rougher seas. As a result of rapid ice melt in 2011, a female polar bear reportedly swam for nine days nonstop across the Beaufort Sea before reaching an ice floe, costing her 22 percent of her weight and her cub. As climate change melts sea ice, the U.S. Geological Survey projects that two thirds of polar bears will disappear by 2050." [2]

[0] https://en.wikipedia.org/wiki/Advanced_very-high-resolution_... [1] https://web.archive.org/web/20210426213549/https://www.usgs.... [2] https://nwf.org/Educational-Resources/Wildlife-Guide/Mammals...

From your wiki link:

"AVHRR data have been collected continuously since 1981"

ChatGPT was off by a decade!

I hope nobody will confuse an anecdote about a handful of bears from 2004 with robust science.

Robust science? You mean NY Times or Chicago Tribune?
No, with the work done by people actually observing and counting polar bear populations.

At any rate, going back to the original non-bear related claims that you're picking a fight with, those outlets were in both cases reporting measurements and claims made by scientists.

Indeed, you could argue that they aren't reliable and the reality was different, but then you'd have to concede that in the past "consensus climate science" has been wrong across the board and thus that this is also a possibility today.

I think in reality the claims made about basic weather stats back then were probably true, or at least as true as they could get at the time. Climatology was too new and too small to have been politicized in the same way it is today. And newspapers had a different ethos around trying to present facts neutrally, they also were less politicized than today. But by all means, argue that the global consensus of scientists (both US and Soviet no less) was wrong.

What an outstanding comment. You put much more effort in it than the person you replied to really deserved.
Thanks! :) Glad someone appreciated it.