as dumb as a mushroom
Think, for a moment, about lignin itself.
It's this complex structural biopolymer made by trees. It's what makes trees woody. And it's totally, transcendently worthless to everything else on earth. There's a tremendous amount of stored energy there -- this being why wood burns -- and nothing can get at it. Millennium after millennium, the accumulation of woody debris starves the atmosphere of carbon dioxide and poisons all of the earth's fresh water. Insofar as anything living has the capacity to suffer, everything is.
Eventually, bracket fungus figures out a way to break down lignin. In a matter of a few hundred thousand years, the quantity of atmospheric carbon dioxide triples, and the amount of atmospheric oxygen plummets. The giant insects that dominate the Earth begin to die. Temperatures rise. The oceans acidify. Almost everything dies. [Cretaceous–Paleogene mass extinction, 65.5 My ago]
Go back further, and disruptive species become increasingly catastrophic. For instance, when cyanobacteria discovered photosynthesis and produced oxygen as a byproduct, nothing respirated. These huge mats of bacteria were producing a waste product more toxic than chlorine gas. And it destroyed almost all life on earth, down to the microbiome, not that there was anything other than a microbiome. The ground corroded, crumbled, washed into the sea. [Great Oxygenation Event, 2.5Gy ago]
And then life, by chance, stumbled on a way to use this horrifyingly toxic gas to ride a more efficient biochemical gradient. And that's all there is to it.
In expending all of the Earth's stored carbon, we're acting just like bracket fungus, or cyanobacteria, or the first cycads. We've found a clever chemical trick and are riding the entropic gradient as long as we can, because, at worst, it temporarily relieves suffering, and at best, it gives us more degrees of freedom to someday not act just like bracket fungus.
This is a low bar -- to not be literally as dumb as a mushroom. But the biological incentives of disruptive species, us included, make environmental catastrophe difficult to avert. The dimensions in which disruptive biology is unsustainable will eventually place a burden on biodiversity system-wide. -- Andreas Schou
