— Ted Cruz (@tedcruz) April 16, 2016
Ted Cruz appears to have a vague notion of the carbon cycle in this tweet. It is indeed true that humans breathe out CO2 and that plants consume it. But, of course, he’s trying to use this to say that CO2 is no problem in the atmosphere. This I suppose is a step up from the notion that humans create CO2 — an issue that I’ve dealt with before, Humans Do Not Create CO2.
So Cruz seems to be aware that the carbon atom is just being swaps from animals to plants and back again. But if this is all that is happening, then why is it that CO2 levels have gone up over 20% since 1960? I mean, this is not one of those cases where Ted Cruz can pick one early high year and claim it is actually going down. Temperatures are highly variable, but CO2 stays in the atmosphere so long that its concentrations are very smooth. Here is the CO2 concentration as measured at the Mauna Loa observatory over the last six decades. (The squiggling is the annual cycle.)
So if animals (not just humans) are swapping all this CO2 back and forth, why is it that the level of CO2 just keeps going up? That would be a good question for Ted Cruz and all of the rest of the anti-science conservatives. Even if they know, they would not be keen to admit it. You see, there is lots of carbon that is in the ground. While it is in the ground, it shockingly doesn’t have an effect on the atmosphere. But once it is released from the ground, it interacts with animals and gets turned into CO2 — eventually. And so we get to the atmospheric carbon cycle.
Now most of this is just plants taking it out of the ground. But that is just more of the carbon cycle. And it is ridiculously complicated. Animals eat plants (directly or indirectly) and use the carbon to build their bodies. Part of living is taking in oxygen and breathing out CO2. The plants take the CO2 back in. And when the plants die, they get buried and the carbon is sequestered. The same thing happens to the animals, of course. This is all be very simple stuff that should be taught to all children by the time they finish grammar school.
The Deeper Carbon Cycle
What’s more interesting is what happens to stuff that gets buried. That carbon still reacts with its environment. But in general, those reactions will be anaerobic — without oxygen. And so that carbon, under the right conditions, turns into hydrocarbons. And we have been busy over the last two centuries, pulling those hydrocarbons out of the ground and burning them, thus releasing CO2 into the atmosphere. And that is why the concentration of CO2 at the Mauna Loa observatory is so much higher today than it was in 1950.
Now I know: this is all kind of complicated and very science-y. It’s much easier to say, “CO2 is what every human breathes out; every plant, in turn,consumes CO2.” And if you are an incurious person — or just a demagogue — that’s where you stop. But it offends me. If Ted Cruz wants to deny science, fine; that’s his right. But I wish he wouldn’t use some minor bit of science to justify his science denial. Science isn’t about saying, “I know one thing, so let’s stop talking.” The carbon cycle is a beautiful thing. Ted Cruz is a great symbol of everything that is ugly about humanity.