The Congo vs. Sahara-Sahel once more

OK, so commenter “Norman” asked me at Roy Spencer’s blog to clarify my position on whether a “more IR active atmosphere” would necessarily produce a higher average annual surface temperature at the bottom of that atmosphere. His inquiry in full:

Kristian

Then you would also agree that increasing GHG in the atmopshere (the quantity makes a difference since it decreases the heat out) will lead to the end result of a warmer surface?

Good. That is what the basic point is all about.

Does the amount of GHG in the atmosphere change the equilibrium temperature of the Earth’s surface?

In your other writings you have states some GHG is necessary but the quantity does not matter. what is your current understanding?

More GHG warmer surface?
Less GHG cooler surface?
Or No change once a certain amount is present?
If in both cases the solar flux to surface remains the same.

So what do we mean by a “more IR active atmosphere”? Well, a proponent of the AGW idea (that of the anthropogenically “enhanced GHE”), like Norman here, would simply say: more “GHGs”. But what does this actually entail? It would lead to an atmospheric column that is more opaque (that is, less transparent) to outgoing surface IR. The idea is that the so-called “GHGs”, the IR active gases (and clouds, mind you), would absorb it more strongly, sort of “capture it” on its way out, and reradiate it in ALL directions, not just the upward one, thus diminishing the net flux of IR moving away from the surface and in the direction of space. And what is this net flux of outgoing IR from the surface? It’s the surface radiant HEAT loss, its Qout(LW).

So Norman’s central claim is this one: “(…) increasing GHG in the atmopshere (the quantity makes a difference since it decreases the heat out) will lead to the end result of a warmer surface (…)”

Well, will it? What does empirically based data from the real Earth system have to say about it?

We return to Africa. Continue reading

What caused the current ToA radiative imbalance?

First the SW (that’s measured reflected SW at the top of the atmosphere (ToA), basically an expression of Earth’s albedo). TSI (incoming sunlight) at the ToA minus reflected SW (albedo) at the ToA equals the ASR (“absorbed solar radiation”) at the ToA, the actual radiant HEAT (net SW) transferred from the Sun to the Earth system as a whole:

(ERBS Ed3 + CERES EBAF Ed2.8 vs. ISCCP FD; tropics, 1985-2004 (20 years).)
Continue reading

UAH v6 vs. CERES EBAF ToA

Happy New Year to everyone!

There is a very good reason why the trend and general progression of tropospheric temp anomalies since 2000, as rendered by the new UAH.v6 dataset, are most likely correct. (Read this post to understand why it was necessary for UAH to update their tlt product from its version 5.6 in the first place.)

The reason is that they both match to near perfection the trends and general progression of incoming and outgoing radiation flux anomalies, as rendered by the CERES EBAF ToA Ed2.8 dataset, over that same period. They’re all flat …:

ASR vs. OLR

Figure 1. Incoming radiant heat (ASR, “absorbed solar radiation”) (gold) vs. outgoing radiant heat (OLR, “outgoing longwave radiation”) (red) at the global ToA, from March 2000 to July 2015. Continue reading