It seems that you don't understand where the extra heat is coming from in global warming. It's not coming from the combustion of fossil fuels directly. The heat is coming from the sun, and it is being trapped by greenhouse gases, just as when your sealed up car sitting in the sun heats up, the heat is not from combustion of the fuel in the tank. It's also from the sun, and being trapped by glass.
That is incorrect (the usual word is closed, not enclosed, but I'll assume that you are speaking in thermodynamic terms). Energy from the sun passes through that magnetic field and impacts the surface of the earth. Most of it returns to space outside that magnetic field either as reflected light or reradiated absorbed energy, which is generally heat (infrared), and maybe a little visible light if the object is hot enough to glow. But some is absorbed by greenhouse gases on the way back up, and some of that is reradiated back down.
But back to the fate of man, I believe that it is already too late to avoid catastrophe. Catastrophic weather is already here, and will continue to worsen. There will be a huge toll to pay in animal and plant life, and great human suffering. It's just the way people are. I see humanity as having a smaller, noble head end, and a large, obtuse tail end, and unfortunately, it's the butt end that calls the shots. Humanity has been ignoring the head end for decades now, because that's what humanity does.
But man will survive this. Global warming may thin the human herd and lead to a lot of human (and animal) suffering, but it won't be the end of man or of life on earth. But that's the price we'll pay because of humanity's unwillingness to prevent disaster, but rather, only to respond to crises. It's not a coincidence that the talk about climate change is just now ramping up a bit. Man had to wait for the land to be scorched, flooded, and blown sufficiently to act.
WHERE DOES THE EXTRA HEAT COME FROM:
You correctly identified CO2 as a greenhouse gas (which stays in the atmosphere for thousands of years). Methane is another important greenhouse gas (which stays in the atmosphere for about 12 years). You correctly understand that greenhouse gases allow high frequency light to enter the earth (going through the CO2 and methane without much trouble), but once sunlight hits the surface of the earth, it changes to a lower frequency, then greenhouse gases trap that lower frequency light so it cannot escape back into space....thus heating the earth as if it were in a greenhouse.
The
extra heat comes from extra CO2. Fossil fuels (oil, coal) are mined, burned to make heat and manufacture items, and that liberates the CO2 trapped in the fossil fuels. A slight temperature change would liberate a huge amount of frozen CO2 in the ocean. The hotter it gets, the more the poles melt and liberate trapped CO2. The more the poles melt, the lower the albedo
(less light reflecting off of the ice caps), which will warm the earth further.
President Donald Trump pointed out that there are new coal energy plants that don't pollute (they trap pollutants before they get out).
The manufacture of electric cars also pollutes. We must figure out a way to cut that pollution.
TOO LATE TO AVOID CATASTROPHE? NO....BUT WE HAVE JUST ONE CHANCE, I THINK:
My friend says that God has shown us the way by erupting the Pinatubo volcano. That set back Global Warming about a year. Unlike a regular volcano that heats the earth (due to magma/lava) but also due to the release of greenhouse gas (such as CO2), a super volcano tosses chemicals deeply into the upper atmosphere, where they will do some good, and releases a huge amount of SO4 (which forms sulfuric acid (acid rain)) in aerosol form, and creates ash that blocks sunlight from getting to the surface of the earth. If we could mimic a super volcano by tossing the same aerosols into the upper stratosphere, and making soot to stop sunlight, we might be able to reverse Global Warming (careful not to reverse it too much or we will make an ice age). We don't have to toss the huge amount of dirt into the air (that just falls out anyway when a volcano erupts). We could get the chemicals into the air with a rocket, rockoon (balloon that carries a rocket to a higher altitude so it doesn't require as much fuel), balloon, or charge atoms and shoot the charged particles with an electric gun.
It is too late for any one conservation measure, and too late for a combination of all known conservation measures.
We are doomed unless we modify the atmosphere as the Pinatubo volcanic eruption did.
We're supposed to be more intelligent than animals, but animals didn't wreck this problem and cause their extinction, we did.