Climate change: How fast does it happen?

 A story about climate change.
A true story.

     The science department head at W C Eaket Secondary School was a member of the American Association for the Advancement of Science. She received their weekly journal, and placed it in the school library, where I read it most weeks.
     Every so often, there were papers on weather and climate modelling, which was developing quickly as computer power increased. The models were based on weather data laid down in ice-cores, tree-rings, layers of silt on lake bottoms and swamps, and so on. These data are good for many thousands of years in the past, but obviously not for millions of years. The geological record supplies data for those long range climate changes.
     Small changes in climate such as the Little Ice Age in the 1500s-1600s (which killed off the Viking Greenland colony) were used to test the models. These were strong models because they were based on large amounts of data. If they worked well, they were run backwards beyond the range for which there was much data, to see if they described the climate as known from geology. They were also run forward, to see what could happen if the CO2 continued to increase to the levels known to have existed millions of years ago.
     The tests were designed to guide further development of weather and climate models. The models varied in the weighting of different factors known to affect the weather, estimated and known rates at which the effects occurred, and different ideas about the feedback loops between these factors. As better data became available, the models were tweaked. Because of their differences, the models were in fact tests of different theories of weather and climate change. Weather prediction models are so powerful now that we expect a three- to four-day forecast to be reasonably accurate. Back then, one day was considered good. When I was a child, we expected weather forecasts to be updated between morning, noon and evening.
     The results of the climate models were, as they say, interesting. The authors reported on and discussed the successful models, the ones that closely described the known history of the weather and climate. Most of these models predicted continuing slow changes in climate like the ones known from the past.
     A handful of models in the early to mid-70s predicted very sudden changes in climate. Changes that didn’t take thousands or tens of thousands of years, but a few hundred years, or even less. The authors were uncertain what to do with those. It wasn’t clear how to decide whether these models were any better or worse than the ones that predicted slow changes. The authors' conclusions were cautious.  As I recall the theme of their discussions, it was along the lines of  “If these models that predict fast changes are accurate, then the currently rapidly rising levels of CO2 in the atmosphere could cause rapid changes in climate.”
     Those papers have stayed with me. Some time later, I learned about the mathematics of chaos. A chaotic system cycles through a series of changes with minor variations from one cycle to the next. Think of the seasonal cycle of weather.  But if one variable exceeds some critical value, the system shifts into another state. This new state will cycle through a different series of changes.
      Climate is a chaotic system. As with any chaotic system, a fundamental question is how quickly the shift can occur. Some chaotic systems change so fast that we speak of a “tipping point”. There is increasing evidence that climate is such a system.

Links
Little_Ice_Age
Climate_model
Global Warming

Proofread and edited 2024-07-28

Societies and their Environments: Collapse, by Jared Diamond

 

    Jared Diamond. Collapse. (2005) Or How Societies Choose to Fail or Succeed.
     Diamond begins his survey of failed societies with an elegiac account of Montana, which is over-crowded and over-exploited, and will suffer some kind of ecological collapse unless the individualist values that make Montana attractive to the incomers radically change. And that’s the over-arching thesis: that the values that enable societies to thrive will, sooner or later, clash with ecological (and therefore economic) reality. Then the choice is stark: adapt or die. For all societies depend on the natural systems they exploit.
     These systems may change naturally (very small shifts in temperature or rainfall can make the difference between a garden and a desert). More often, they are over-exploited: the prime example of this is Easter Island. He ends his survey with a rather depressing look at the ways in which our misallocation of resources damages the ecosystems that sustain us. His prime example is mining, which we practice as if there were no long-term costs. He does see some hope here and there, in the shift towards pollution reduction in China, for example, but overall, we are still making choices based on values that made sense when resources were scarce, surplus wealth was difficult or impossible to accumulate, and ecological damage was localised and its effects on people and other life forms was limited.
     Diamond’s work shows that the choice is never between “the economy” and “the environment”, but between values, attitudes, and desires. The fundamental issue is that humans, like any other creatures, depend on the environment. We humans have changed the Earth more thoroughly than any other organism. That has made us very successful, if you measure success by our numbers and the variety of habitats that we occupy.
     But that success contains within it the seeds of our own destruction. We operate on the same imperative as all other life forms: be fruitful and multiply. If we continue to operate on the values of economic growth and profit, if we fail to understand that the standard of living is not about money, we will destroy our civilisation. If we do, will the humans who survive the inevitable population crash learn from our mistakes? The history of societies that destroyed themselves suggests that’s unlikely.
     Recommended. ****

Footnote 2023-03-156: Recent research indicates that the rain forests help create the rain that sustains them. The implication is that once a  the rain forest is logged out, the savanna that replaces it will be drier than the forest, which in turn suggests that it will eventually devolve into desert.

Angel Catbird: To Castle Catula

     Margaret Atwood, Johnnie Christmas, Tamra Bonvillain. Angel Catbird: To Castle Catula (2017) The second instalment of the Angel Catbird saga, as nicely done as the first. Angel and his friends travel to Castle Catula, picking up owls as allies along the way, and adopting an orphan kitten. A couple of goddesses also join the alliance against Dr Muroid and his rats. His evil will of course implode in the finale, since he doesn’t understand that his power depends not on control but on leadership. A couple of female white rats will no doubt figure in his defeat. I expect Volume 3 before Christmas. Recommended. ****

An invader that isn't: The Narrow World by Brent Bonacorsos.

Watch this video by Brent Bonacorso. Science fiction with a difference. About 15 minutes of your time well spent. Marie K sent me a link which led to this.

Political Anecdotes and War Stories: Memoir by Charles Lynch

    Charles Lynch. You can’t Print THAT! (1983) Lynch describes himself as a Political Voyeur, and that he is. He’s also an excellent story-teller, his natural talent honed by the demands of newspaper reporting. He’s also opinionated, a small-c conservative, with a grudging respect for the Liberal party, and a somewhat uncritical enthusiasm for the Progressive Conservatives, with whom he shares a superstitious fear of debt. He loved fishing and music. He began his career before the 2nd World War, was a war correspondent, spent most of his working life in Ottawa. He thinks Canadian politics (and history) is anything but dull, and his tales prove it. Extremely readable, recommended, a sourcebook for anyone who’s contemplating writing a history of Canadian politics in the 60s and 70s. More about him on Wikipedia.  ****

Late Louis L'Amour: End of the Drive

      Louis L’Amour. End of the Drive (1997) Posthumous collection of short stories and a novella “found in an old box” by L’Amour’s son. Mostly early work, you can see L’Amour learning the craft. He tries out standard plots, such as the thieves who betray each other, the son who grudgingly admits his father’s wisdom, the con-man unmasked, etc. I didn’t finish the novella, though, it’s uses a plot L’Amour has used many times: the villain who sows suspicion, the hero who must clear his name, the girl who mistakes her feelings, etc. A treat for any fan, a good read for anyone who likes well-done pulp. **½

Why GDP is a bad idea

An economist and an accountant are walking along a large puddle. They get across a frog jumping on the mud. The economist says: "If you eat the frog I'll give you $20,000!"

The accountant checks his budget and figures out he's better off eating it, so he does and collects money.

Continuing along the same puddle they almost step into yet another frog. The accountant says: "Now, if you eat this frog I'll give you $20,000."

After evaluating the proposal the economist eats the frog and gets the money.

They go on. The accountant starts thinking: "Listen, we both have the same amount of money we had before, but we both ate frogs. I don't see us being better off."

The economist: "Well, that's true, but you overlooked the fact that we've been just involved in $40,000 of trade."