Dr. Roy Spencer has made a challenge to the Slayers/Principia folks who keep insisting the greenhouse effect doesn’t exist at all. For example, see the front page claim at right from the Principia web page where they claim the greenhouse effect is “bogus”.
My view has always been that it exists. and has been effectively modeled as well as observed/measured (up to a point, so far I don’t know of a full scale measurement being done for the entire vertical column of the atmosphere), but likely isn’t the catastrophic issue portrayed by alarmists due to climate sensitivity likely being low.
Dr. Spencer’s challenge is quite simple and rooted in science; to prove their case, he simply wants them to make a simple model like this one below to demonstrate the absence of a greenhouse effect, while at the same time handling the measured energy budget of the Earth.
So far, he’s attracted lots of blowback rhetoric, but no serious takers. I doubt there will be.
Dr. Spencer sums it up pretty well as to why a cogent rebuttal is not likely:
If and when they answer my challenge to provide a quantitative model of surface temperature change, I might change my mind. But they must first provide a time-dependent model like that above which involves energy gain and energy loss terms, which is the only way to compute the temperature of something from theory. Those energy gain and loss terms must be consistent with experimental observations, and (of course) the physical units of the terms must all be consistent.
But I don’t see how they can ever do that, because they will ignore the hundreds of watts of downward emitted IR radiation from the sky, an energy flux which is routinely observed with a variety of instrumentation, and explained with well-established theories of radiative transfer and laboratory evidence of the infrared absorption characteristics of various gases.
And later in comments:
All they have to do is provide an energy budget equation that produces the observed average surface temperature of the Earth, and support the values for the energy fluxes with observational evidence. They have not done this. In fact, they cannot do it because they would need to find an extra 300+ W/m2 of energy somewhere, otherwise they cannot explain observed surface temperatures.
As he says its “put up or shut up” time. Read it all here:
I doubt the Slayers/Principia folks will learn anything from Dr. Spencer’s challenge, as they’ve reached almost a cult like status in this belief, and once it reaches that status, minds start closing to the possibility of the central idea being wrong. Most of the belief is predicated on a simple misinterpretation of the Second Law of Thermodynamics and how the greenhouse effect in the atmosphere (a misnomer) actually operates, slowing the transfer of Long Wave Infrared from the surface of the Earth to the top of the atmosphere. You’ll see the “a colder object can’t heat a warmer object” argument being bandied about as proof of their belief, but it is a strawman argument that doesn’t represent what actually goes on in the GHG slowing of LWIR transfer to TOA.
In fairness, I’ll borrow a phrase from a skeptic movie title: “Not evil, just wrong“.
These folks mean well, but they’ve latched onto an idea that just doesn’t work. Some of the main players, such as Doug Cotton and John O’Sullivan have gotten so entrenched and angry that they have made persona non gratas of themselves here and at some other blogs.
“If you have the facts on your side, pound the facts. If you have the law on your side, pound the law. If you have neither on your side, pound the table.”
Like Dr. Spencer, if and when they are able to provide a simple working model of the atmospheric energy balance that matches their theory with observations, I’ll be happy to take another look at the idea here.
In the meantime, it’s just a Sisyphus style table pounding time sink, and one has to know when to step away from the argument until such time something of substance is presented.