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Saturday, February 28, 2015

Mann Overboard

Michael Mann is one of the leaders of the global warming crowd, so what he says carries a great deal of weight.  Well now Mr. Mann is out with an article on the Huffington Post which responds to the fact that data from the satellite system which was designed to get the most accurate temperature readings possible for the planet shows that there has been no warming for over 17 years.  Here are the two key paragraphs of Mann's response:

No, climate change is not experiencing a hiatus. No, there is not currently a "pause" in global warming.

It is true that Earth's surface warmed a bit less than models predicted it to over the past decade-and-a-half or so. This doesn't mean that the models are flawed. Instead, it points to a discrepancy that likely arose from a combination of three main factors (see the discussion my piece last year in Scientific American). These factors include the likely underestimation of the actual warming that has occurred, due to gaps in the observational data. Secondly, scientists have failed to include in model simulations some natural factors (low-level but persistent volcanic eruptions and a small dip in solar output) that had a slight cooling influence on Earth's climate. Finally, there is the possibility that internal, natural oscillations in temperature may have masked some surface warming in recent decades, much as an outbreak of Arctic air can mask the seasonal warming of spring during a late season cold snap. One could call it a global warming "speed bump." In fact, I have.

The funny thing is that Mann claims to be a scientist, but then he ignores the data.  Before looking at the argument, however, we need to know one bit of background.  The satellites whose readings show no increase in temperature measure the atmosphere, not the surface.  These satellites were needed (or so we were told) because surface temperatures are unreliable.  A nearby factory or city or other human habitation could change the surface temperature a bit.  The air temperature, however, would be much more indicative of actual natural conditions.  As a result, a network of satellites were launched which can measure the temperature of the atmosphere all around the world.

It is against this background that Mann's statements must be reviewed.  First, he says that Earth's "surface" warmed less than the models predicted.  In other words, he ignores the data that shows no increase in the atmospheric temperature and goes back to surface readings which are supposed to be less reliable.  Even then, Mann has to admit that the models got it wrong; warming of the surface was less than predicted.  What he leaves out is that the difference between the prediction and the actual fact was so large that it exceeded the amount which would let the model be viewed as correct.  More simply, the temperature difference was so great that the models are wrong.  If Mann were to look at the more precise satellite data, then the models were VERY wrong.

But let's consider Mann's three factors that skewed the results (or so he says.)  The first one is actually a howler.  Mann says that there are gaps in observational data.  This is the same Mann who refuses to look at the precise global readings from the satellites that were designed to get those very accurate readings.  Of course, Mann can't look at that precise and global data because it proves he is wrong.

Second, Mann says that the models are wrong.  Oh, he phrases it that some small things have been left out of the models.  One of these omitted items is the output of the sun.  Is he kidding?  The sun is the principal driver of weather on Earth.  Variations in solar output have a profound impact on our planet.  This is what they omitted?  No wonder the models are wrong.

Third, Mann speaks of internal oscillations that "may have masked" increases in temperature.  Note that Mann does not tell us that these oscillations did mask the increase.  Instead, he just speculates that they may have done so.  Where's the data to support this?  Speculation is not enough.

For a long time, I have been waiting for a coherent response to the current pause in atmospheric temperatures from the global warming crowd.  This article by Mann tells me that they don't have such a response.


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