Lately I've become quite interested in climate science. Or the lack thereof. And I've become ever more sure that the whole CO2 is causing climate change is b.s. Would you like to know why?

How do we know what molecules are greenhouse gasses? The atmosphere is made up of most nitrogen (N2) and it's about 80% of the total atmosphere. Oxygen (O2) is around 20%. Is oxygen and nitrogen greenhouse gasses? No. Why? Because they're paired molecules, and don't have any dipole moment. The greenhouse gasses are water vapor, CO2, methane, ozone and nitrous oxide. These molecules have dipole moments. Which is just another way of saying that at the molecular level, they vibrate and wiggle. The frequency that they wiggle corresponds to the frequency of the light spectrum that they can absorb.  

Methane can wiggle in a few different ways, and for every way it wiggles, it absorbs a different band of the infrared spectrum. Two of those bands that it absorbs very well is almost absent from the radiation the sun produces, shining down on earth (the visible light spectrum and UV light) and the light that the earth's surface reflects back into space (infrared). One of those bands does, but it's insignificant because water vapor is already absorbing that energy and water vapor is vastly more abundant in the atmosphere than methane. In fact, water vapor accounts for 90% of the greenhouse effect.  

CO2 is a linear molecule. O=C=O. CO2 can wiggle in only a few different ways. Wiggle movement #1) The oxygen atoms can spread out and pull in at the same time. This is called symmetric vibration. Wiggle movement #2) one of the oxygen atoms pushes in while the other pushes out. This is asymmetric vibration. Wiggle movement #3/#4) The oxygen atoms can move back and forth together or flap up and down together. Think a bird that's flapping it's wings. Now Wiggle #1 and Wiggle #2 we can completely ignore because the frequency that CO2 can absorb from these movements are nearly absent from our sun. The only thing that matters is Wiggle #3/4, and that movement absorbs infrared frequencies at 15μm. There's some crossover effect, so CO2 is very good at absorbing infrared frequencies between 14-16μm.

Below is a black body emissions curve. The yellow is the frequencies that shine down on earth from the sun. The red are the frequencies that the earth's surface shines back into space. If those frequencies are blocked from reaching space, the earth warms up. So let's look at the distribution curve. If we take a look at a black body radiation curve for the light that is reflected off the surface of the earth, it spans primarily between 4-50μm, peaking around 10μm. When we look at water vapor's absorption of the infrared spectrum, it makes a U shape, with two peaks between 4 and 7μm and a 2nd peak between 14 and 20μm. And oh, did I mention that there's 20 times more water vapor in the atmosphere as CO2? It's 4000 times more abundant than methane. The vast majority of the radiation that CO2 can trap is already being trapped by water vapor.  
 
But doesn't more CO2 still mean more heat is trapped? No, not really. CO2 traps heat at 15μm VERY well. Like it's already getting all that it can get, until poor ole 15μm is plum run out to be trapped. Let's put it this way. Currently, atmospheric CO2 is at 414 parts per million (ppm). Pre industrial it was 285ppm. At 140ppm it's so low that plants begin to suffocate. Well, forget 140ppm, where plants start dying, lets go to a mere 20ppm. Guess what? CO2 is already absorbing 50% of all the infrared at 15μm. 70% at just 40ppm. CO2 sucks up every last bit of 15μm infrared until there's only a itty bitty tiny bit left, and that all happens before we even get enough CO2 for plants not to suffocate. This is called CO2 saturation, and it's why raising CO2 levels is literally nothing to worry about.  
 
So what's causing climate change? Water vapor? Nope. The amount of water vapor in the lower atmosphere has increased by a tiny bit, but in the troposphere, the stratosphere it's actually decreased. Methane has moderately increased, but it's in such small quantities that it's measured in parts per billion instead of parts per million. Is it because we have more ozone? Nope. While ozone is a greenhouse gas, it's not absorbing much from the earth's surface, it's mostly absorbing UV radiation from the sun, and it does so at such high altitudes that it wouldn't effect the warming on the surface of earth.  
 
What we should note is that the temperatures today are not on par with the temperatures in the 1930's when we experienced the dust bowl. Temperatures decreased from the 60s to the 80's, despite that CO2 was going up all this time, and temperatures rose again starting in the 90's. Throughout this time, greenhouse gases have remained fairly steady on average, with moderate increases in methane and a bigger increase in CO2. Human beings are not causing the temperature of the earth to increase. We're just not. CO2 is not causing the warming. Water vapor isn't causing the warming. So what is?