The collapse

A couple of weeks ago, I wrote about the spike in atmospheric oxygen concentration -- by some estimates, rising to 35% -- during the Carboniferous Period, triggered by explosive growth of forests, and allowing arthropods like insects, arachnids, and millipedes to grow to enormous sixes.

The good times, though (for them at least), were not to last.  Around three hundred million years ago, there was a sudden drop in oxygen and rise in carbon dioxide.  This triggered rapid climatic shifts that resulted in the Late Carboniferous Rain Forest Collapse, which saw a major alteration from the swamp-dwelling plants and animals at the height of the period to species that could tolerate the dry heat that was to persist throughout the next period, the Permian.  (This set up the rise of reptiles, which would see their peak in the dinosaurs of the Mesozoic.)

Artist's depiction of the mid-Carboniferous swamps (ca. 1887) [Image is in the Public Domain]

The source of the excess carbon dioxide was very likely volcanic.  Besides the fact that lava can contain dissolved gases (mostly carbon and sulfur dioxide), the heat of the eruptions may have caused the oxidation of the plentiful limestone and coal deposits formed during the earlier lush, wet part of the period -- a precursor of the much bigger disaster that was in store fifty million years later, when at the end of the Permian, the Siberian Traps erupted and tore through a huge amount of the sequestered carbon, causing widespread global anoxia and climate change, and the largest mass extinction ever.

By some estimates, ninety percent of life on Earth died.

But the rain forest collapse at the end of the Carboniferous was bad enough.  A study that came out this week in Proceedings of the National Academy of Sciences found the anoxia/hypoxia hit the oceans the hardest, where the oxygen levels rapidly dropped by between four and twelve percent, with a commensurate rise in dissolved carbon dioxide.  When carbon dioxide dissolves in water, it produces a weak acid -- carbonic acid -- lowering the pH.  Organisms that make their shells out of calcium carbonate, like mollusks, brachiopods, and corals, literally dissolved.

You ready for the kicker?

The study's estimate of the rate of carbon dioxide release during the Late Carboniferous Rain Forest Collapse is a hundred times smaller than the rate we're putting carbon dioxide into the atmosphere today through burning fossil fuels.

"This is a huge discovery, because how do you take an ocean sitting under an atmosphere with much more oxygen than today and permit this?" said Isabel Montañez of the University of California - Davis, senior author of the study.  "The message for us is, 'Don't be so sure that we can't do this again with our current human-driven release of carbon dioxide.'"

The problem is, the current administration is in the pockets of the fossil fuel industry, and is doing their level best to pretend this isn't happening, and to discredit anyone who says it is.  Worse, actually; they've cancelled funding for any scientific research about climate.

Because apparently "la la la la la la not listening" is now considered wise political policy.  This, despite warning signals like the eastern half of the United States sweltering this past week under the most extreme heat wave we've had in over fifty years.

So I'm expecting studies like the one released this week by Montañez et al. to receive exactly zero attention from the people who actually could work toward addressing this situation.  It brings to mind a quote from Upton Sinclair, uttered almost a century ago: "It is difficult to get a man to understand something when his salary depends on his not understanding it."

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