Home > Critical Thinking, Current Affairs, Dystopia, Musings, Philosophy sans Sophistry, Reason, Secular Religions, Skepticism > Anthropogenic Climate Change is a Form of Secular Apocalypticism: 2

Anthropogenic Climate Change is a Form of Secular Apocalypticism: 2

In the previous part of this series, I wrote that over the past 540 million years, there hasn’t been much correlation between atmospheric levels of CO2 and average global temperatures. Believers in the secular religion of anthropogenic global warming might attribute this to continents having different relative and absolute positions in the past due to plate tectonics. Therefore, I urge you to have a look at this YouTube clip of the reconstructed positions and movements of continents over that period. As you will notice pretty quickly, the relative and absolute positions of many continents does change a lot over that period. FYI- relative positions of these continents (more precisely their constituent cratons and shields) over that time-span has been deduced via a combination of techniques ranging from geology, paleontology, chemical and isotope analysis etc.

The fact that atmospheric levels of C02 ranging from 20x to 2-3x those seen today had little effect on average global temperature over such a long time-span and variety of continental arrangements, if anything, bolsters the argument about it being a relatively minor player in the larger scheme of things. Also note that most modern continental landmasses, except India and Australia and to some extent South America were near their current latitudes by 80 million years (at 5:10 in first clip) or about 15 million years before dinosaurs went extinct. Furthermore, the Eocene Thermal Maximum (at 5:38) occurred when most major continents were pretty close to their current latitude and longitude. Also, the most recent cycle of ice ages began about 6 million years ago (6:24-6:34) when all continents were, for practical purposes, at their present location.

Let us move to a related topic, namely for how long has the current ice-sheet covering Antarctica been around. As you will soon see, the answer is more surprising and complicated than you might have expected. So let us first talk about the position of that continent relative to the geographical south pole for the past 540 million years, as seen in second clip. Long story short, some part of the modern Antarctic continent has been within the southern polar circle (south of 66.5 degrees S) for the past 400 million years.. which is, geologically speaking, a pretty long time. More surprisingly, the geographical south pole has been within the land mass of Antarctica for at two extended periods within those 400 million years- from 0 to 120 million years ago and 260 to 350 million years ago. To put it another way, Antarctica has been the south polar continent (often along with Australia) for a bit longer than vertebrates first crawled on dry land.

So how was the climate in Antarctica during the past 400 million years? Well.. for a good portion of that period, it was what we would today classify as temperate, albeit with an interesting twist due to being loacted at extreme southern latitudes. It may have been warmer (subtropical?) during the period between 240-400 million years ago, but once again with that peculiar seasonality. The more peculiar and relevant part is that Antarctica has been pretty close to its current position for the past 80 million years and had a cool temperate climate for at least half that period. In other words, having long dark winters and long bright summers did not cause that continent to become a barren and frozen wasteland for many tens of millions of years.

The first evidence of some glaciation on that continent in the past 200 million years seems to have occurred around 40-35 million year ago. So what caused this cooling? Well.. the current explanation is that it was due to the Antarctic Circumpolar Current (see figure below) which started up after both South America and Australia had separated from Antarctica to a point where such a current could form. The popular conventional view is that ACC created a cold barrier around Antarctica about 35 million years ago and it hasn’t ever gotten warmer since then. Indeed, official information sources on the internet try to endlessly repeat this lie. To be clear, nobody is denying that the ACC has been there in its current form for the past two million years. But the evidence for climate on Antarctica for past 35 million years is far more complicated than many “credentialed experts” are willing to admit in public for reasons that will soon be obvious.

As many of you might have guessed, our knowledge about the geology and paleontology of Antarctica is much sparser than for other continents. Nevertheless, a number of surveys for plant and animal fossils have revealed evidence which simply does not fit with the popular version of Antarctica being a frigid wasteland for the past 35 million years. For example, there is decent evidence that parts of Antarctica had extensive tundra like vegetation throughout the Oligocene to the mid Miocene (24-14 million years ago). Even conifers existed on that continent as late as 15 million years ago. But the most striking evidence concerns the last forests in Antarctica, which existed as late as 2.3-2.6 million years ago.

To be clear, the last forests on that continent were restricted to certain regions and their tree biome was largely made up some of most cold-resistant species. Having said that, we can use the types of tree and micro fossils found at those sites to estimate contemporary climatic conditions. A cold-resistant genus of trees known as Nothofagus aka southern beeches are well represented in those fossils. As luck would have it, living members of that genus can be found in the southern Andes, parts of Australia and New Zealand. To make another long story short, the region of Antarctica where those fossils were found would have to be about 30 degrees Celsius warmer than it is today for even the most cold-tolerant species in that genus to exist. Also, there is a lower temperature limit for vascular plants.

In the next part of this series, I will go into some detail about the fossil and chemical evidence for why we think that those southern beech forest in Antarctica were so recent. As you will see, there are other independent lines of evidence to support the contention that Antarctica looked and felt a lot like certain parts of Northern Canada and Siberia as late as 2.3-2.6 million years ago. But such streams of evidence also create a huge problem for the popular model of Antarctica as an icebox in the past 35 million years. I mean.. why did Antarctica go through pretty large and incomplete cycles of partial glaciation and deglaciation within the past 40 million years, when it was close to its current location, isolated from other continents and levels of atmospheric CO2 were in current range or lower. Also, why did the continent become a frozen icebox only in past 2.3 million years? As you will see in next part, reality has a way of derailing theoretical models.

What do you think? Comments?

  1. MikeCA
    July 14, 2019 at 9:50 pm

    CO2 is only one factor affecting the climate. Solar energy output and the earths reflectivity are other important factors.

    Right.. did I ever mention that I seriously considered going to grad school for astrophysics but chose something which pays more money.

    As far as the solar output bullshit is concerned, it is a G2V type yellow dwarf- which is a fancy way of saying that the Sun is a very mediocre main sequence star. Consequently, its light (and total EM) output is very steady and cycles by barely 0.1% over the course of a full solar cycle lasting 8-13 years. While it is possible that the young sun (4 billion years ago) was about 40% fainter than today, let me remind you that the process of it getting brighter is incredibly slow. Also even a sun without sunspots is only 0.1% fainter than one with tons of them.

    Moving on.. the total albedo of earth changes a bit only under two conditions after plants started growing on land about 400 million years ago. First, extensive planet-wide glaciation aka ice ages. Two, if the degree of cloud cover or amount of aerosols in the atmosphere change a lot. The degree of cloud cover tends to remain fairly constant over long periods of time. So basically, only aerosols from large volcanic eruptions or massive magma outpourings (and maybe large asteroid/ comet impacts) can temporarily alter the atmosphere enough to affect whole planet albedo.

    • MikeCA
      July 15, 2019 at 9:56 am

      Did I ever mention that I actually have a PhD in astrophysics? I also worked at major institutions/universities for a few years before I left for something that paid more money.

      You should investigate the faint young sun paradox, an idea popularized by Carl Sagan at the time I was still in graduate school. Short version is computer models of sun’s evolution suggest the energy output of the sun 4 billion years ago was only 70% of what it is today. With that energy output all water on the earth should have been frozen but the geological record clearly shows that liquid water was abundant and there is not really any evidence for glaciers until about 2.5 billion years ago.

      Fixed the typo, and now it reads 4 billion years in my previous reply. Yes, I am aware that many models of stellar evolution suggest that main-sequence stars gradually brighten over their life. In fact it is very likely that sun was only 50-60% as bright as today during the Hadean eon aka 4.6-4.0 billion years ago on Earth. We also know that there were very long ice ages like the Huronian around 2.4 billion years ago. Having said that, we also know the ocean or at least parts of it were always warm enough for single celled life to exist since the end of the Hadean (and likely even prior to that).

      There have been lots of attempts to resolve this paradox and explain why the early earth was so warm. The early atmosphere was very high in CO2 and greenhouse effect from that and methane is at least part of the explanation in most theories of why the earth was warm enough for liquid water.

      Many greenhouse gases in the Archean (4.0-2.5 B yrs ago) and Paleoproterozoic (2.5-1.6 B years ago) were almost certainly much higher than today. However we also do not much about the size of continents during those eons. Look up Supercontinent cycle and Supercontinents. We therefore cannot properly model the hydrological cycle during those eons.

      The important point is models predict the sun has been gradually outputting more energy over time so 500 million years ago the energy output would be less than today.

      Given that the sun is a main sequence star, any change in energy output would be fairly linear and the rate would be incredibly small. Even over a period of 500 million years, it would something around 5% (which is still quite significant). However, changes in solar output cannot explain events such as the Cryogenian (720-635 M yrs ago) or more precisely what caused it and what ended it. Similarly we do not understand why the earth (especially continents) was mostly ice free over past 250 million years even though atmospheric CO2 levels changed a lot over that period.

      https://www.youtube.com/watch?v=UevnAq1MTVA

  2. nyolci
    July 18, 2019 at 8:21 am

    Again, there’s quite a lot of bullshit around, even in the fringes of science. But hard science (like climate science and modern physics) isn’t like that. You damage your reputation with shit like the above, sorry.

  1. July 18, 2019 at 9:00 am
  2. July 21, 2019 at 10:53 pm

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