Extra CO2 in the air from human sources is supposed to put us on a route to catastrophe but the message is a bit garbled.
Some say the extra CO2 heats the air and that is enough to do the trick. Others accept (correctly) that that is unlikely due to the thermal inertia of our oceans and their cooling effect on the air so they propose an ‘ocean skin’ theory whereby warming of the topmost molecules on the ocean surface from extra downwelling infra red radiation from extra human CO2 in the air is supposed to reduce the natural energy flow from sea to air so that the oceans get warmer and then heat the air and kill us off that way.
The term ‘ocean skin’ is rather a misnomer because in reality the area of interaction between air and water is a haze of mixed water and air molecules in constant dynamic interaction.
Interestingly, and importantly, the power of downwelling infra red radiation is insufficient to get past the region involved in evaporation. In that respect it is unlike soar radiation which penetrates the ocean to hundreds of metres depending on wavelength.