PragerU offers "thought-provoking questions"

The Florida department of education recently approved videos from PragerU to be played in Florida classrooms for student instruction. "PragerU," writes the Guardian, "is not an actual university. It has no accreditation. It is a conservative media company whose goal since its founding in 2009 has been to spread rightwing ideology to adults and children." As NPR reports, "its founder admits indoctrination is its goal," with audio of him saying so.

What kind of indoctrination? There are, for example, PragerU videos with a cartoon Christopher Columbus (himself a brutal exploiter of indigenous people) and a cartoon Frederick Douglass each downplaying American slavery, which seems to be a thing lately in Florida education. The idea is that slavery in America was nothing special; everyone was doing it around the world.

Here's one that particularly stuck in my craw, because it nicely illustrates the mindless way right wingers "reason" about things they don't understand.

NPR explains how "PragerU Kids has a video questioning the origin of climate change. In this one, a narrator sets up a conversation between a girl and her parents."

Narration from the PragerU video: "But when her anxiety gets high and she tells them that fossil fuels will soon lead to a climate disaster, they challenge her with some thought-provoking questions. They encourage her to consider how the planet has been warming and cooling since prehistoric times, long before carbon emissions were a factor. Can she explain that?"

Can she? She's just a child. A better question is, can they? 

No, they can't.

The "don't worry, the climate has always been changing" dismissal is pure right-wing lunacy, and not because it hasn't been changing. Of course it has always been changing; learning about how and why the climate has changed helps us understand what's going on now, and what is unique about our present circumstances.

There are a couple of possible insinuations in the PragerU shrug. One is that because the climate has always been changing, humans can't be causing it to change now. That's not just specious; it's stupendously ignorant.

Another is that because the climate has always been changing, change is the normal order of things, so we shouldn't fret about it. Don't worry your pretty head, little girl.

An additional insinuation, if you want one, is that carbon emissions weren't "a factor" in prehistoric warming, so linking humanity's carbon emissions to today's warming is suspect. That, too, is spectacularly ignorant. Carbon emissions have always been a factor, whatever the cause of warming. As any climate scientist will tell you, carbon is fundamental. Atmospheric carbon dioxide concentrations (along with less important greenhouse gasses) are what determines the earth's temperature.

One easy lesson from an always (where "always" means over geologic time scales) changing climate is that when the climate moves toward extremes of hot or cold, it's guaranteed to be a pretty awful situation from the standpoint of humanity. You'd very much prefer that it didn't happen. As recently as 20,000 years ago, enormous mile-thick ice sheets covered Canada, and extended down into the U.S. Montreal would have to wait for more congenial times to have a possibility of existing.

There have also been long periods in the earth's geologic past when the planet was unimaginably hot, far hotter than today, with no ice sheets anywhere on Earth, and sea levels hundreds of feet higher than today. What a hellscape that must have been. The girl is right to be concerned.

Although we can glibly acknowledge that the climate has always changed, from the perspective of human civilization, the climate has been remarkably stable. Change might be the normal order of things over eons, but the past 10,000 years, which encompasses the entirety of human civilization, has been a period of moderate and stable temperature and sea level, with very little variation. Some experts argue that civilization was able to take hold and flourish precisely because of temperature and sea level stability. It's a basic fact that human civilization has never experienced any of the extremes of climate variation that the worried girl is being asked to explain. But that is changing. At this very moment we are moving outside the zone of stability that civilization has always enjoyed, with grave implications for humanity.

And we're doing it to ourselves. Very, very rapidly. The rate of change today far exceeds what has occurred naturally in even extreme warming and cooling events. An ice age, for example, takes many thousands of years to develop. That gives all interested parties lots of time to adapt, gradually. Importantly, the biosphere itself has plenty of time, with species and indeed entire biomes migrating to lower latitudes as ice sheets descend from higher ones. Even the rapid warm-up that occurs at the end of an ice age is far slower than the rate of warming we're experiencing today. Whereas the climate warmed by upwards of 9 °F over a period of around 7,000 years coming out of the last ice age, it has warmed by around 2 °F over just the past century. Likewise, sea level rise is accelerating, and the rate could soon exceed that experienced in the big melt coming out of the last ice age. Whatever amount of sea level rise ultimately occurs, it's guaranteed to be disruptive to our coastlines, and the disruption is already underway.

We can, at least, scratch ice ages off our list of climate change concerns. Because the climate "forcings" that instigate ice ages are incredibly weak, there will never be another ice age as long as humanity is around to stop it. You might find that hard to believe, but it is true. The upshot is that humanity does indeed have the ability to alter the climate quite dramatically, and we're doing so right now, rapidly pushing the climate outside the zone of stability that human civilization has enjoyed for its entire existence.

Because the risk is now all on the side of planetary warming, and always will be henceforth, it's instructive to study how the climate has warmed (and then cooled) naturally over periods of tens of millions of years. Such very long term variation occurs because the movement of carbon in and out of solid Earth reservoirs is normally not balanced. Solid Earth reservoirs are massive geologic stores of carbon distinct from more rapidly changing surface reservoirs such as atmosphere, ocean water, forests, and soils. Carbon can move into solid Earth reservoirs (which are thus carbon sinks) faster or slower than carbon is emitted from them (in which case they are carbon sources). Carbon moves in both directions, but at different rates depending on what's happening with the earth's geological activity.

The main mechanism for carbon moving out of the atmosphere and into solid Earth sinks is the weathering of rocks, whereby atmospheric CO2 reacts chemically with rock minerals and is carried away by streams and rivers to be deposited on the ocean floor.

Carbon moves out of solid Earth reservoir sources and into the atmosphere via geologic processes involving plate tectonics and vulcanism. (If you're thus tempted to think that volcanoes are causing present-day warming, please don't.)

The movement in and out of sources and sinks explains why the earth experienced an extraordinary increase in temperature beginning at the start of the Cenozoic era 65 million years ago, followed by a very long term cooling trend over tens of millions of years up to the present. Perhaps we should blame it all on India.

At the beginning of the Cenozoic, the continent of India was situated by itself in the Indian Ocean (they didn't call it that back then) off the coast of Africa. India's continental plate commenced an unusually rapid movement (around 8 inches per year), marching across the Indian Ocean and taking square aim at Asia. Along the way, India's plate rode over the ocean crust and its carbon-rich deposits laid down by the large rivers that had drained southern Asia for eons. The crust and its carbon deposits were subducted beneath the overriding plate under enormous heat and pressure, which caused melting and metamorphism of the ocean crust, and released carbon-bearing gasses that came to the surface via volcanic eruptions and other geologic features.

Thus was carbon rapidly transferred from solid Earth reservoirs into the atmosphere, where it caused the climate to dramatically warm. I say "rapidly," but I use that term relative not to human timescales but to geologic ones. The warm-up that ensued occurred over millions of years, peaking 55 to 50 million years ago in what's called the "Paleocene-Eocene Thermal Maximum," or PETM. Warming on the order of  9 to 16 degrees Fahrenheit occurred. Crocodiles and palm trees existed north of the Arctic Circle. It was surely hellish at lower latitudes. The entire planet was ice free; as a consequence, sea levels were hundreds of feet higher than today.

So yes, Virginia, carbon is "a factor."

This explanation is instructive but not complete. Two huge pulses of methane hydrate releases from the upper layers of the sea floor, taking not more than 1,000 years each, amplified the PETM warming. But these methane releases, caused by the melting of normally frozen methane hydrates, were feedbacks operating in the context of an overall warming as a consequence of carbon dioxide imbalance caused by plate subduction over a carbon rich ocean crust. Imagine that: Science really can explain why the climate changes.

It's instructive, too, to note the magnitude of the imbalances that were driving the long term warming. Such source/sink imbalances can change the atmospheric CO2 concentration on the order of one ten-thousandth of a part per million per year, which amounts to 100 ppm over a million years. Contrast that with the present, where atmospheric CO2 is increasing at the rate of 2 ppm per year. Today, CO2 is increasing at a rate that's four orders of magnitude (a factor of 10,000) faster than the source/sink imbalances that drove temperatures stupendously high in the early Cenozic, under "natural" conditions. All today's carbon is being pumped into the atmosphere by humanity's burning of fossil fuels. Human activity has increased atmospheric CO2 by 140 ppm since the beginning of the Industrial Revolution. Natural factors driving the climate are clearly far weaker than anthropogenic (human caused) ones, and it isn't even close.

Finally, thanks to an overall cooling trend over the past 50 million years, the earth has accumulated far more methane hydrate deposits than existed in the run-up to the PETM. If today's methane hydrates were to be released in a sudden pulse—something that will likely happen if the current warming trend continues—it will be game over for humanity. A pulse of that magnitude would take 100,000 years to unwind.

Back to our story. When India slammed into Asia, things changed rapidly, geologically speaking. India's continental plate rode underneath the Asian one, causing the uplift of the Tibetan Plateau and the forming of the Himalayan Mountains. You know, Everest and all that. As India settled into place and the subduction-caused emissions stopped, the brand new mountain range exposed large amounts of fresh rock to the forces of weathering. As we have seen, rock weathering is the primary mechanism by which carbon is moved out of the atmosphere to hard Earth reservoirs. As already noted, a very long term cooling trend occurred, over tens of millions of years, as the weathering continued. A bit over 30 million years ago, glaciers returned to Antarctica, for the first time in tens of millions of years. Cooling continued but at a slower rate. In a cooler climate, the magnitude of temperature fluctuation between ice ages and interglacial periods increased.

What does all that have to do with today? It demonstrates that the concentration of carbon dioxide drives the climate, which, as I said, is fundamental. And it underscores how seriously concerning is humanity's own carbon emissions, which are occurring at a far faster rate than even natural ones that drove immense climate changes. It also shows that today's climate is warming faster than under natural conditions in the geologic past. Bad as things already are, with all the droughts, flooding, storms, wildfires, and heatwaves, we're still in the early stages of our ill-advised climate experiment. We've not nearly reached PETM-like temperatures, but we absolutely have the ability get there through human action alone.

And isn't that remarkable? The girl is correct to be worried. Thinking about how the climate has always changed is no comfort at all. I said above that any venture outside the climate norms to which civilization is accustomed is likely to be "awful" for humanity. What's amazing is that this time it's all humanity's doing. Don't blame nature for the catastrophe we ourselves are willfully creating right now, and don't use nature to excuse our inaction.

Doesn't that put PragerU's glib dismissal in correct and shameful perspective? In blathering that the climate has always changed, PragerU models reasoning through non sequitur, which does great damage to young minds that ought to be taught facts and consequences appropriate to their grade level, and to think critically. PragerU wants to teach kids to be as mindlessly ignorant and unable to reason as their adults. What a disgraceful perversity masquerading as instruction, all blessed by Florida's department of education. Luckily, Florida's teachers will have something to say about all this, and I'm betting they'll shout hell no to the idea of allowing right wing propaganda into their classrooms.

Copyright (C) 2023 James Michael Brennan, All Rights Reserved

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