These geoengineering proposals should be understood as mitigation strategies to be implemented after we have reduced carbon emissions, since even then we still

These geoengineering proposals should be understood as mitigation strategies to be implemented after we have reduced carbon emissions, since even then we still have a problem. But this one seems very dubious. >Speaking in terms of thermodynamic, we can say that chimney prevents adiabatic cooling of a rising parcel of air. Normally, when hot air freely rises in atmosphere, it expands as it gets higher and pushes the surrounding air. That causes surrounding air to heat and rising air to cool. That process continues until equilibrium is reached. At that point air stops its ascending. Unlike freely rising parcel of air, the air in the chimney is restricted in its horizontal expansion and thus, it is not free rising. When air rises in the chimney it also expands but only into upper direction. It compresses the layer of air above it, heats it up and loses its own heat. At the same time air below does the same thing. And that’s how it goes all the way until the chimney exit: layers of air are being pushed and push themselves. That results in maintaining the same amount of heat in every layer of air, and that is how the chimney works. This explanation ignores gravity. Air above you exerts more pressure on you than air below you, albeit by a tiny amount. But when the only thing moving is air in a 5-kilometer chimney, you can't get something for nothing. For intuition, just imagine the chimney is full of water. The water at the bottom is obviously under more pressure than the water at the top. The chimney faces the same consideration, but the ideal gas law applies. Furthermore, the equation used in the "Calculations" section: >q = Π dh2 /4 [ (2 g (po - pr) h ) / ( λ (l pr / dh) + ∑ξ pr ) ]½ is sourced from this website: http://www.engineeringtoolbox.com/natural-draught-ventilation-d_122.html http://www.engineeringtoolbox.com/natural-draught-ventilatio... which rather obviously works from the assumption that the chimney is placed inside of a heated house. This all seems to be a sort of Sokal effect in climate science, I'm afraid. The paper 'SubiculumCode cited does not really analyze the thermodynamics used for the chimney and points more to the unrealistic dimensions (1 kilometer diameter and 10 kilometers high).