Two Climate Model Studies


There are two new climate-modeling studies that you might find interesting.

The first study uses global satellite temperature data trends for the period January 1979 through June 2009.  The abstract of this work says:

“The past 12 to 13 years show cooling using both satellite data sets, with lower confidence limits that do not exclude a negative trend until 16 years.”

(The original indicated “..until 16 to 23 years” but that was corrected.)

loehle_fig6_uah

Loehle’s Chart Shows UAH Data and the Model Projection

Loehle’s conclusions are that:

“…the satellite data shows a statistically significant cooling trend for the past 12 to 13 years, with it not being possible to reject a flat trend (0 slope) for …..16 years.  This is a length of time at which disagreement with climate models can no longer be attributed to simple LTP. “

The climate models (General Circulation Models) did not predict this cooling period.  And if the cooling period last for 16 or more years, it could be argued forcefully that the GCMs are not valid predictors of future climate.

I am a skeptic about the GCMs and do not believe that rational people should be planning their future based on their output.    My experience with curve fitting was usually less than successful so as much as I would like to, I can’t say I am willing to buy into this model’s output either.   To read more about this, click here

The other study discusses a New Method to Quantify Climate Modeling Uncertainty.

The good part of this study is based upon the conclusion “…that the range of uncertainty in climate projections may be greater than previously assumed.” The study group looked at global temperature projections under three conditions.  One case, A1F1, is high economic growth and continued use of fossil fuels for the remainder of the century, another, B1, is a major reduction in fossil fuel use and the last case, A2, is a middling scenario.

The study found:

“Interestingly, when the variance or “error bars” are taken into account, there is no statistically significant difference between the projected temperatures resulting form the high fossil fuel use, A1F1 scenario and the middling A2 scenario up through 2050. “ See more of the story here.

The authors included the obligatory statement that we can bank on even higher temperatures and more heat waves after 2050 if fossil fuels are not curtailed.

Still it is refreshing to see that the error bars keep getting bigger as the modelers are beginning to get a little more nervous about their skillfulness in predicting future climate.

Can you explain to me why we have politicians that want to bet our future on climate models that can’t seem to get it right?

Cbdakota

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