Monday, August 3, 2015

"The Day after Tomorrow" is no Closer

High on the list of things that Everybody Knows is the claim that the Gulf Stream is slowing down, delivering ever less heat to the Northeastern US and Western Europe and inevitably triggering a new Ice Age.  The “evidence” comes from proxy data and computer climate predictions; the reality of the problem was attested by the 2004 eco-porn movie “The Day after Tomorrow”, in which New York is eaten by a glacier.

There are just a few little problems with this story.  First, there is the use of the word “evidence” to describe the predictions of models and proxy estimates.  Let’s be clear about this: the way science progresses is to 1) collect data, 2) propose one or more ideas, called hypotheses, that might explain the data, 3) use quantitative models of these hypotheses to generate predictions of future observations, and 4) carry out a new round of experiments designed to test (and discriminate between) the competing hypotheses.  Steps 1 and 4 deal with evidence (data); step 3 is not evidence; it is informed conjecture, as-yet untested speculation, whose sole purpose is to motivate a search for critical new data, NOT to predict the future. 

Second, the role of disaster movies is not to teach science; it is to sell tickets.  Anyone who derives his understanding of climatology from disaster movies is a fool.  This judgement includes those whose knowledge of asteroids comes from Bruce Willis.

Third, (a most inconvenient truth): we actually have direct observational data on the flow of the Gulf Stream covering some 23 years of recent history.  Shock, horror: we don’t need to rely on hypothetical speculation!  A research team headed by an eminent expert on oceanic circulation, Prof. H. Thomas Rossby of the Graduate School of Oceanography of the University of Rhode Island and his team, have been measuring the speed of the Gulf Stream since 1992.  Their study was based on observations made on the Bermuda Container Lines’ ship Oleander, which makes weekly crossings from Elizabeth NJ to Bermuda.  The Oleander carries a Doppler current meter that directly measures currents to a depth of about 600 m.  And what are the results of their research?  They find no evidence whatsoever that the speed of the Gulf Stream has decreased over the time of their study. 

Why do we get so much bad science in the press? Because untested conjectures are often much more interesting than the truth. Which sells more papers (or movies), the "news" that we are on the verge of a new Ice Age, or the demonstrated fact that everything is going on normally? By ignoring the distinction between untested hypotheses and replicated fact, they mislead the public, misrepresent the science, and sell their undigested pap as news. 

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