The point of this article is to test this without using expensive technology, but instead common household items.
First we need CO2, and I chose to get it from "sparkling mineral water", which is just water with CO2 added, and can be bought in any store.
The labels must be removed, (by immersion in hot water,) to let in sunlight, and there must be a water basin to keep the gas in the bottles while the temperature probes are inserted.
To fill the bottle with CO2, just shake the it upside down, and the bubbles will press the water down. Do this with the opening under water, and no air will come in. There were more than enough CO2 to press out all the water.
And then one needs an equal bottle with ordinary air, for comparison.
Both bottles were placed in the sun, at the same place, so they should get equal amount of sunlight, heat, and cooling.
And then put 2 equal thermometers inside the bottles. Unfortunately, that was impossible to do with the cooking thermometer I had chosen, without letting the CO2 out, so I put it in the air bottle instead. The CO2 bottle got an accurate scientific thermometer; physicist that I am. But I recommend getting 2 equal thermometers, testing them toghether to see how precise they are, and using a deeper water tray, so the probes can be easily inserted.
And then wait a while for the temperatures to stabilize.
CO2: 33.3 °C, Air: 36 °C
And what did I get? Did I get higher temperature in the CO2 bottle?
I got higher temperature in the air bottle instead.
And I tasted the gas in both bottles afterwards to be sure I had not switched them, and I had not.
It is easy to taste CO2, but do not inhale too much!
Perhaps the cooking thermometer is quite inaccurate?
So I put the scientific thermometer toghether with it in the air bottle to test this.
Scientific thermometer: 40.2 °C Cooking thermometer: 46 °C
Yes, the cooking thermometer is inaccurate, but the temperature really
is higher in the air bottle, since the scientific thermometer shows a
higher temperature there.
So I put it back in the CO2 bottle to double check.
Scientific thermometer: 37.9 °C
And the temperature is indeed lower in the CO2 bottle.
Better use 2 thermometers for more precise results.
So, I have become even more skeptic of the whole global heating debacle.