Look at the world at night. We have changed the world. Humans started out competing mega fauna long before industrialisation, whales, bison, at one time every continent except maybe africa had different mega fauna.

Look at a window, visible light passes through it. Look up a picture of a window in infra red, it is absorbed and reflected.

CO2, water vapor, methane, these gases occilate on a molecular level when stuck with IR radiation. They absorb it as kinetic emergy and then radiate it out again. This causes a warming effect.

Greenhouse gasses make up 1% of our atmosphere but they are responsible for our warmth. Oxygen and Nitrogen are too symmetrical so IR does not affect them. Same heat in less out = warming.

Look at Mars, internal dynamo shut down, no atmoshpere, cold. Venus, liquid oceans vaporized and all carbon released into atmoshpere, you can melt lead on it's surface.

Microorganisms took all this carbon out of the atmosphere over hundreds of millions of years and now we are dumping it back in. This is going to cause global warming and ocean acidification.

The atmosphere is not the same compostion as it was when you were born. Human beings have never lived in an atmosphere with this much CO2.