What do you chaps think of this?


Well-known Member

ABSTRACT: We examine tropospheric temperature trends of 67 runs from 22 ‘Climate of the 20th Century’ model
simulations and try to reconcile them with the best available updated observations (in the tropics during the satellite era).
Model results and observed temperature trends are in disagreement in most of the tropical troposphere, being separated by
more than twice the uncertainty of the model mean. In layers near 5 km, the modelled trend is 100 to 300% higher than
observed, and, above 8 km, modelled and observed trends have opposite signs. These conclusions contrast strongly with
those of recent publications based on essentially the same data. Copyright 2007 Royal Meteorological Society

Stephen Wilde

Active Member
The models are not yet good enough to provide a basis for policy decisions.

Someone should tell the IPCC.


The models are not yet good enough to provide a basis for policy decisions.

Someone should tell the IPCC.

I have notified them of your doubts and they have replied in the positive with grateful thanks.

No doubt there will be an update. :)

Stephen Wilde

Active Member
"To be sure, this isn't a demonstration that the tropical trends in the model simulations or the data are perfectly matched - there remain multiple issues with moist convection parameterisations, the Madden-Julian oscillation, ENSO, the 'double ITCZ' problem, biases, drifts etc. Nor does it show that RAOBCORE v1.4 is necessarily better than v1.2. But it is a demonstration that there is no clear model-data discrepancy in tropical tropospheric trends once you take the systematic uncertainties in data and models seriously. "

The above is the 'conclusion' from that realclimate link.

So what does the above paragraph mean ?

1) It admits that the models and the observational data are not matched.

2) It lists a very few of the very many inadequately known variables and attempts to hide their huge number with the term 'etc'.

3) Notwithstanding points 1 and 2 it then tries to say that there is no clear model-data discrepancy but only if one 'takes systematic uncertainties in data and models seriously'.

So, if one takes such systematic uncertainties 'seriously' they say that that somehow renders the mis- match 'not clear'. I really don't see that. Taking systematic uncertainties 'seriously' seems to me to involve appreciating that there is indeed a clear model-data discrepancy because both the model designs and the observational data are both systematically uncertain due to the inadequacy of our current knowledge and data gathering techniques.

Is their final assertion just linguistic juggling and therefore the very opposite of reality or have I missed something ?

In essence they seem to be saying that the mis- match arises due to uncertainties in the data and that those uncertainties in the data are not matched by equal or greater uncertainties in the models. I fear that that is a wholly untenable position because it claims that the models are more accurate than our best observations of the natural phenomena which we are trying to understand.

The reason that such a contention is untenable is quite simply because the models were constructed from past data which is likely to be even more uncertain than recent data.How do they account for their assumption that the models are accurate enough for prediction and as a basis for policy decisions when they admit that the observational data is and always has been systematically uncertain ?

They just rely on most readers not being able to see through the fog which their words create.

Corey USA

Active Member
If certain aspects of the positive and negative feedback loops are left out in the models its going to fluctuate widely from reality.

For example I would be curious if they included the effects sulfur from china's trucking. What could sulfur combine with chemically that might produce a known or unknown gas that is known to cool or warm the atmosphere.

We still don't know fully how the ocean currents play their role in warming or cooling the earth and what local effects it will have.

Do we fully understand the impact acidification of our oceans will have on the climate indirectly?

In the End it comes down to changing human behaviors and actions that will have the biggest impact on climate, environment and resources.

With poor management of our world trees I no longer consider trees to be an unlimited resource, We are abusing the resource beyond regeneration. Trees can effect the local climate and weather when enough are cut or planted.

Forests trap moisture especially the triple canopy variety of the rain forest. this in turn effects moisture in the air.

water vapors or lack of can have an effect on climate based water vapor being a green house gas. This comment was in reflection of someone else's comment in one of the older threads here.

If these things are not added to the model then of course they are going to be skewed.

One of the factors that gets left out of the models that concerns me is the methane release positive feedback loop . I don't know if it was included in the IPCC report in the fact section or not. the grape vine was saying it was left out since it was an unknown factor in regards to how fast the quantity and when it will be triggered.

The latest video from AVForums

Podcast: Sky Glass, Epson Laser Projectors plus Home Cinema Subwoofers and More…
Subscribe to our YouTube channel
Support AVForums with Patreon

Top Bottom