Lovely bullshit title to the paper. I can see why you are captivated by it. Enthalpy is about heat (vibration and motion) and thermodyanmics. CO2 remains a well mixed greenhouse gas and growing major cause of global warming. The papers data and sums may be entirely precise, but have nothing to say about radiative capture and redirection of energy by greenhouse gases, such as CO2, across the whole atmosphere. Radiation physics is a very different kind of beast to the distribution of heat as kinetic energy in a volume of air among its component molecules, according to ideal gas laws. If you confuse these concepts you end up with bullshit.