What melting ice reveals

 kw: book reviews, nonfiction, archaeology, glaciology, ice-patch archaeology

There are about 200,000 mountain glaciers worldwide, not counting the ice caps of Greenland and Antarctica. Searching for information about "perennial ice patches" I found statements about "tens of thousands". However, in a couple of areas where the ice patches and the glaciers have been comprehensively mapped, the ice patches outnumber the glaciers.

This matters to archaeologists. A glacier is on the move; that is part of the definition. That means that the ice experiences shearing. The field of glacial archaeology is primarily the study of stuff that is found where a glacier's tongue is melting, and only stone or metal objects tend to survive being squashed and shredded beyond recognition. A perennial ice patch is, also by definition, stationary. Thus, an item that was dropped, lost, or otherwise placed on an ice patch and later covered by snow and incorporated, is preserved in the ice, sometimes for millennia. 

Only the points of arrows and spears survive passage through a glacier. Entire arrows, complete with wooden shaft, fletching, and decoration, and a great many other artifacts made of or including wood, leather, bone, cloth and other perishable materials have been found melting out of ice patches. As the climate shifts, continually, an ice patch will grow from year to year and then partially melt for a few years. Once a perishable artifact emerges from the ice, it will usually rot and vanish within a few years.

The current warming cycle is a boon to ice-patch archaeologists. As reported in The Age of Melt: What Glaciers, Ice Mummies, and Ancient Artifacts Teach Us About Climate, Culture, and a Future Without Ice, by Lisa Baril, the opportunities greatly exceed the number of ice-patch scientists and the available time to study them. This is based on the author's projection that ice patches are melting away, and may all disappear in the next few decades. I will touch on this contention later on.

The field of ice-patch archaeology was jump-started 35 years ago when the ice mummy Ötzi was discovered in the Alps. The story is told in commendable detail in the book. The man's body was dried but mostly intact, and his clothing, weapons and other possessions were nearly all intact and well preserved. Over time, with the development of more and better study techniques, it was found that he was murdered about 5,200 years ago, probably a day or two after a fight of some kind. The ice patch he was frozen into is in a mountain pass; he didn't make it over the pass into the next valley. I call this image, produced using Nano Banana 2, "Ötzi in happier times". Perhaps I should have showed him enjoying a meal with friends.

Being able to recover perishable artifacts greatly enriches our picture of the cultures of the times and places. For example, many wooden poles, some with fabric or leather "flags" attached, have been found in Norway and other areas including the Yukon. They were a mystery for a time, until indigenous people recognized them as "scare sticks" used to keep a fleeing group of reindeer or caribou on a path leading to stacked-stone blinds where hunters waited. Sadly, it has taken quite a while for "professional" archaeologists to learn the value of the knowledge in "the people who live there." This subject arises several times in the book.

The oldest artifact so far recovered from an ice patch is a part of an atlatl found to be 10,300 years old, recovered in Wyoming in 2007. In this case, the window of opportunity was just a day: Craig Lee found an ice patch that included lots of bison dung, and saw a stick poking out. He collected it, called the federal archaeologist for an emergency collection permit, and then checked around for more items. The next day it snowed, a lot. In the nineteen years since, the ice patch has grown, not melted back. In other places, ice patches have melted totally away. No matter which direction the general climate is "going", there is great variation from place to place.

This brings me to the sad subject of the over-hype about a warming climate. Is the climate warming? Yes, absolutely. Is it caused by rising CO₂? Yes, at least in part. Are humans to blame? Partly. It is a fact that in 1800 AD the CO₂ level was 280 parts per million (ppm), and now it is about 425 ppm. In 1897 Svante Arrhenius published his study of the greenhouse effect, in which he predicted that doubling the amount of CO₂ in the atmosphere would increase global average temperature 4°C. However, others with a better knowledge of infrared spectroscopy later published that the effect would be 1°C or a little less. Both were wrong, in different directions.

I worked in infrared spectroscopy in the 1970's. Ten years before that I had reproduced Arrhenius's calculations, so it was easy to apply a better understanding of optical saturation and, so to speak, "hit it in the middle"; my conclusion was 1.5°C for a doubling of CO₂. Our present concentration of 425 ppm is about 1.5 times 280 ppm. Global average temperature has risen about 1°C, which indicates that my calculations are in the right range.

Now let us consider saturation. While the IPCC reports upon which climate alarmism is based do mention saturation, they don't stress it nearly enough. Saturation works this way. A chart of temperature as a function of concentration is not a straight line, but a curve, with two components. Arrhenius described one component this way, that a geometric increase in concentration produces a linear increase in temperature. He predicted that reducing CO₂ from 280 ppm to 140 ppm would reduce temperature 4°C, doubling it to 560 ppm would increase it 4°C, and doubling again to 1,120 ppm would cause a further increase of 4°C, or a total of 8°C, and so forth. This ignores saturation. By a level of 400 ppm, the CO₂ is absorbing almost all that it can absorb. Only a tiny bit more absorption is possible no matter how high CO₂ goes. 

There are very low-level secondary "wings" on the spectral absorption bands that come into play after concentration reaches a few percent, then the temperature rises more rapidly. This is what happened on Venus, where the concentration is more than 20,000 times the current concentration in Earth's atmosphere. We don't have enough fossil fuel to cause that to happen!

Saturation of absorption by CO₂ means that a further increase to 560 ppm—a doubling from the pre-industrial level—will not cause much increase in temperature, if any.

This should not make us complacent. We still need to continue adding more energy sources that don't require burning hydrocarbons. That includes nuclear fission. If CO₂ increases beyond 1,000 ppm it will be harder for some people to breathe comfortably, and the higher it goes, the greater the number of people who will feel the effects. But we need to recognize that it will be a long, long time, if ever, before a battery-powered jet aircraft will be practical, or even possible. And in cold climates, keeping an electric automobile cabin warm uses more power than moving the vehicle. The market for EV's is essentially zero in northern Norway, for example (it may improve when sodium batteries become more common; lithium does very poorly in the cold, but sodium performs very well).

Although I was a bit put off by the drum beat of climate change concern, I really like the book, and I learned a lot. I recommend it.

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A few items I need to mention:

1. On page 27, discussing carbon-14 dating, it says, "This method works well for organic objects up to fifty thousand years old, after which the amount of carbon remaining in organic material becomes vanishingly small." The amount of total carbon remains almost exactly the same. The amount of carbon-14 is what vanishes. C-14 in atmospheric CO₂, from which plants make it into sugar, is 1.4 parts per trillion.
2. On page 66, discussing Pleistocene extinctions, the word "others" is needed: "All of them would go extinct, … but many continued to thrive." Not "many" but "many others" thrived, if "all" of the species mentioned went extinct.
3. On page 203, the catalog of tall Himalayan mountains is called "fourteeners". This term refers to mountains exceeding 14,000 feet in North America. The high Asian peaks, taller than 26,000 feet, are called "eight-thousanders", referring to 8,000 meters, or 26,247 feet.