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Re: What Greenhouse Effect?

One obvious thing to notice in this paper (my 3.0 version has date 11SEP2007) is the reference to R.W. Wood's experiment on greenhouse glazing, circa 1909. Wood made two heat traps, one with glass glazing and one with NaCl (sodium chloride) glazing. The sodium chloride glazing is more transparent than glass and won't trap/block as much IR as the glass. Most references to Wood's experiment acknowledge that restricting convection is what primarily warms a greenhouse. But they state that the temperature of Wood’s sodium chloride trap is nearly the same as the glass trap. The implication is that some IR trapped heating is going on.

Thanks to this paper (and I also read Wood's actual note), it turns out that the sodium chloride trap warmed faster than the glass trap and it reached a higher temperature (65ºC vs. 55ºC). This makes sense because the sodium chloride glazing is letting in more radiation. When Wood pre-filters the radiation going to the sodium chloride trap with a glass overlay, then the two traps have almost the same temperature. Wood says, “There was now scarcely a difference of one degree between the temperatures of the two enclosures” (he doesn't say which one is slightly warmer).

Before reading this paper, I was led to believe that glass covered greenhouses owe some of their increased temperature to trapped IR. Wood’s demonstration failed to show any IR trapping. The idea of IR trapping in greenhouses is so strong in the body scientific, that they can't even state Wood's experiment without bias.

Re: What Greenhouse Effect?

I made a remark on Wood's experiment here: