So, I pointed out in my previous post that Liz Bourke was being snappish about papers dealing with the historicity of matriarchy, or whatever. I wouldn’t dare join in an argument about history — though I think Liz is right to roll her eyes on that one — but, remember the Gaia hypothesis?
A little while ago, with regard to Nancy Kress’ novella “Before the Fall During the Fall After the Fall,” I said something to the effect that Lovelock’s Gaia hypothesis was an example of sophomoric philosophy rather than actual science. I didn’t expand on that at the time, because that wasn’t the point of the post, but this past weekend I took the time to dig out various textbooks and stuff so I could look up details (I’ve never been good with dates, alas). So now I do feel like expanding on that comment.
Now, the actual reason the Gaia thing is so idiotic is that a) it proposes that the entire Earth acts like a single living organism, particularly with regard to maintaining homeostasis (relatively constant environmental conditions), and b) the Gaia “hypothesis” always (always) goes along with a declaration that Human Activity Is Upsetting The Balance of Life and Gaia Hates Us. This is, of course, the exact notion that explicitly underlies Kress’ novella.
Now, never mind that a planet does not in fact have any way to maintain homeostasis and certainly does not behave in any way like a living organism. I mean, how could it? Treating a big ball of metals and mineral as though it was alive is just about exactly like taking your pet rock out for walkies. But never mind. Let’s ask a different question, okay?
Have people EVER managed to do ANYTHING that a planet would EVEN NOTICE, if it were some kind of super-organism?
To answer that question, let’s take a look at Deep Time.
Now, I have some tolerance for people who don’t know the Earth’s history and who think, for example, that the overall planetary climate was stable until people started messing around with the Industrial Revolution. Because, granted, you do get that impression from PBS and other media outlets. But a guy who claims to be a real ecologist, like James Lovelock, ought to know about stuff that happened long before humans were a factor, way back in Deep Time.
Every school kid knows about the ice ages that started about 2.5 million years ago (and are actually still going, since we’re just in an interstadial at the moment — a temporary retreat of the glaciers). But did you know that all those moments when glaciers have advanced were just a chilly breeze compared to the Snowball Earth events that have several times frozen our planet nearly solid? The first of those occurred about 2.45 billion years ago, but the more recent series of Snowball Earth episodes took place only about 700 million years ago – not that long ago, if you can get your attention away from mere human history.
The well-known ice ages affected only continental surfaces and of course ice didn’t reach the tropics, but in the Snowball events, not only all land surfaces froze, but also all the oceans froze solid, to depths of maybe 1000 meters or so. Once you stick a lid across the oceans like that, they actually become chemically decoupled from the atmosphere. With no way for the metals and gasses produced by undersea volcanoes to escape into the atmosphere, all the liquid water beneath the ice becomes toxic. Meanwhile, all water on land would not only freeze, but sublime into the air, so every bit of land surface would be wind up not just frozen, but also bone-dry. With temperatures above the ice hovering around -40 degrees C and the water below the ice toxic, all life on Earth would have been wiped out except for particularly tough organisms, such as weird extremophile bacteria in hydrothermal vent systems and stuff like that. Those Snowball conditions, which occurred repeatedly, lasted probably for about 30 million years at a time. And breaking out of Snowball conditions involves massive outgassing of CO2 and true runaway greenhouse heating, the kind that produces new disasters of its own. Though it sure beats staying frozen.
How anybody who knows about the Snowball events can possibly think Gaia would notice any kind of climate shifts that have taken place during the modern era is beyond me. In fact, the ordinary Ice Ages are plenty to kind of make you wonder about that – not to mention the Medieval Optimum. People do seem to forget that our planet actually does have a history that goes back before we started building factories and keeping cows.
The repeated Snowball Earth events were extremely dramatic, no question, but freezing isn’t the only kind of disaster the Earth has suffered. Of the fifteen or so mass extinctions that have hit Earth’s organisms in the past 500 million years, all were due to other causes. At least five wiped out more than half of all extant species.
The extinction of the dinosaurs wasn’t the biggest-ever mass extinction by a long shot, but it’s the one everyone knows about, so let’s look at that. Everyone knows that one was caused by an asteroid, right, that smashed into the Earth 65 million years ago? But let’s stop for a moment and think about what that was actually like.
When that asteroid hit, the blast was about 10,000 times as powerful as if you took all the nukes in the world and set them off all at once. Tremendous earthquakes and tsunamis wrecked continental shorelines all over the place. Thousands of tons of rock were instantly blasted into the atmosphere. Some of the big chunks fell back down, heating up as they fell through the atmosphere. When they hit, they started fires all over the planet. Over half of the Earth’s forests burned. Think about that. Over half of all the forests on the whole planet.
The fine dust and all the smoke from the fires almost completely blocked sunlight from reaching any part of Earth’s surface for months. A global climate that had been fairly tropical (because, among other things, there was twice as much CO2 in the atmosphere at the time as there is now) suddenly became frigid. Before that, though, the impact caused heating of the atmosphere which made atmospheric oxygen combine with normally nonreactive nitrogen, forming nitric acid, which fell in a heavily concentrated acid rain all over the planet. By the time the acid rain was over, the top 300 meters of the oceans, where most marine life is concentrated, was acidified to the point that the seawater dissolved the shells of any animals with calcareous shells. Everyone talks about the dinosaurs, but actually roughly sixty percent of all the living organisms on Earth were wiped out, in the oceans as well as on land.
What I’m saying here is, although strip mines look ugly, and although the beautiful, stunning megafauna of the Pleistocene were almost certainly wiped out by stone-age people who didn’t know better; and although people today, who definitely do know better, are certainly morally culpable whenever they carelessly wipe out a huge swath of rainforest or an irreplaceable species, nothing people have ever done in all history even begins to approach the destruction the planet has suffered over and over in the past. And the human-driven extinction going on now doesn’t begin to compare to the big mass extinctions of the past.
So. That’s why the Gaia thing makes me roll my eyes. It’s not just the ridiculousness of treating a ball of rock as though its carbon cycle is an actual kind of homeostasis, it’s the even greater ridiculousness of thinking that a planet that’s undergone what ours has could even begin to notice anything people have ever done.
If you want to complain about the way people abuse the environment, fine, there’s lots to complain about. If you’re outraged at African elephants being killed for ivory, or whatever, I’ll join you in waving that banner. But I’d prefer that you please pick some grounds less asinine than the Gaia hypothesis, before you design your banner.