## Arctic Ice

I find the the trend in sea ice age over the last ten years or so a conceptually difficult metric.
Ine of the problems as I have mentioned before is that the less ice you have to start with the less the percentage of multi year ice appears to be in a good recovery year.
Counter intuitively this means that years with low percentage multi year ice are actually making good recoveries.
This might help explain the contradiction between a 10 year pause in ice volumes, sought of a recovery in a way from the previous high falls and a downwards trend in multi year ice for 10 years which also fits in with recovering, not diminishing ice in the Arctic?

## In defense of Roger Pielke jun

Atomsk,
I get the drift that the scenario itself is not the outcome
and that the scenario does not have to be real.
and that therefore, a scenario may not be a prediction, only a conditional prediction.

The problem is that you cannot usefully cleave [split] a scenario and a prediction in this way without losing the meaning of both words.

For your analogy I agree that one does not usually try to prove the precept is wrong to show that the outcome is wrong.
That is because a precept or scenario is not falsifiable, You determine the input.
If one uses a different input one would would have to put up a different output.
A scenario can only be a scenario if it is predicating [and hence predicting] a future outcome.

If the situation the scenario is attempting to mimic is shown by time to be different to the assumptions you used that is not a failure of the scenario.
Reality is a different scenario and you cannot falsify either by comparing the outcomes.

RP and I have never tried ” to claim a conditional projection failed, since they claim a predicted scenario didn’t occur.”
It is wrong to say that.
A more apt analogy would be that the child placed it’s hand on the hot stove and it did not burn.

In this case the fact that you claimed the stove was hot enough to burn the child’s hand is wrong.
You did not put enough wood in the fire [wrong assumptions] or did not light the match [check the starting conditions were as you said] or did not run it long enough [dodgy thermometers].

I do not mind people bagging my arguments but I do mind people bagging their opponents unjustly.
Fair enough with me, i make misunderstandings.
Roger Pielke is a true scientist, brought up in a scientific family and background and does not make basic misunderstandings of concepts.like scenario’s and it is just plain wrong to say that he does.

ATTP
“If there’s warming then I think you still need some kind of flux imbalance. My understanding is that quite soon after a perturbation (say, an increase in atmospheric CO2) the LW fluxes can return to balance, but the cloud feedback leads to an imbalance in the SW fluxes, which then dominates the subsequent warming.”
izen “The increase in surface temperature is a result in the greater thermalisation of OLR from the surface in the lower layers of the atmosphere, not in a imbalance in the energy flux for the whole system.”

“If there’s warming then I think you still need some kind of flux imbalance” This bit is very true but emphasises the problem raised by Izen.
If warming is occurring there must be a flux imbalance.
We see this every day when the sun comes up. The GHG concentration does not change **[much] but the atmosphere heats up and the radiating layer goes much further outward.
So some energy has been garnished from the sun and thermalised.

But what happens when the heat input stabilizes say just after midday[** more provisos].
For a short period of tome the energy in equals the energy out as everything is in balance.
Then the radiating layer contracts as the atmosphere cools.

Does the CO2 level affect this pattern? No [* more provisos].
What it does affect though is the amount of atmospheric thermalisation that day.
The atmosphere will be warmer with more CO2 in it.
Not in 100 years but at that lovely moment of equibrilation.
Which occurs every day, usually after midday, though it might occur several times around that time due to albedo cloud changes.

ATTP “quite soon after a perturbation (say, an increase in atmospheric CO2) the LW fluxes can return to balance,”
OK
” but the cloud feedback leads to an imbalance in the SW fluxes, which then dominates the subsequent warming.”

Not sure of this. Feedbacks occur including clouds which is more part of the expected imbalance due to the change in incoming heat.
The SW fluxes can only be variable due to the variable albedo? They temporarily alter the actual heat input which is why you might have several moments of equilibrium usually after midday. The longterm feedback effect amplification is more due to increased GHG [water vapour] in the air raising the ECS not the SW effects.