Radiation windows

8. The re-opening of night time re-radiation windows (Walter Jehne)

Up to 60% of our observed global warming to date has resulted from systemic increases in the night time minimum and mean temperatures relative to former cooler levels. This increase is associated with higher night-time humidity levels and consistent with the increased, persistent humid hazes.

By contrast, the previous natural rainfalls, often in the late afternoon and early evening, would have removed much of this humidity and these hazes from the air leaving clear starlit evening skies that would enable much of the heat that had been absorbed during the day to be re-radiated out to space, unobstructed by the water vapour blanket and it greenhouse warming effect. This night time re-radiation caused many, often tropical areas, having cooler night-time temperatures than now.

While this rain would have removed much of the water vapour greenhouse effect it would not have altered the CO2 concentration or its greenhouse effect which would be the same day and night.

The fact that there is such a significant reduction in the greenhouse heat retention effect from removing just the water vapour greenhouse component but not the CO2 component effect, reinforces that water vapour is the dominant greenhouse gas and that we can reduce its warming effects via inducing its removal via rain so as to re-open these night-time radiation windows.

We have no equivalent mechanism for reducing the much smaller CO2 greenhouse gas warming.

Here’s Walter again, talking about radiation windows at about 1 hour 50.