So how does CO2 cause the trapping of heat?
There are many good summaries on the net, I found a few just in a few minutes.
The water vapour effect per the post from 'quality posters only' is noted, but as water vapour itself is a product of temperatures created by greenhouse gases, and is in a feedback loop, we need not focus on that. The resultant effect from water vapour in areas where they were not before is one of the direct consequences of GW on the population.
I gave the microwave analogy not as a dismissive answer, but alluding to the differing effect of wavelengths in the visible spectrum from UV to IR on different molecules
Quite simply, heat via sunlight comes easily through the atmosphere because it is mostly on the UV end (put on your sunscreen), but the heat that radiates back to space from the earth is mostly at the IR (infra red) end and interacts with greenhouse gases, and returns to lower atmosphere.
The 'job' of the natural level of greenhouse gases is in fact to trap this heat. If it were not so, and CO2 in particular was non existent - and not at the 200 to 280ppm level it has 'always' been (millennia), then the earth would be 33 deg C lower than what it is today.
The moon for example has an average of -50 ish C, over 100 C in day, -150 C at night.
Increasing the CO2 artificially (what we are actually doing), increases the amount of IR radiation trapped in lower atmosphere and increases temperature in a non linear fashion.
CO2 is now 412ppm from pre industrialisation 280ppm.
CH4 has increased to 1.8ppm from 0.75ppm
If you do not accept this basic science - greenhouse gases trapping heat- then you also do not accept that the greenhouse gases at its natural level is keeping the earth liveable at 33 deg higher than what it should have been, and therefore you do not believe it may become un-liveable due to too much GHG
You may as well go to the witchdoctor if you get a 90% blockage in arteries.
The other bad effects - measured- of CO2 are things like increased ocean and freshwater acidity, coral damage, fauna being affected. Already measured in Great Barrier Reef
We do not question the elements in the periodic table existing, we do not question how they interact with each other and how they relate to each other in groups. We do not ask for more understanding nor even question their existence.
Yet when a scientist tells you how they can measure ice cores for CO2, or paleo oceanographic fossils for what the temperature would have been, we pooh pooh it.
Just weird. Why is it even an argument?