Monday, April 11, 2016

                    IT'S  NOT  DEAD-- IT'S JUST HIBERNATING


AS  ORIGINALLY MODELED ,  'NUCLEAR WINTER'  LIVED UP TO ITS NAME:  IT  HYPOTHESIZED  MONTHS OF SUBZERO COLD AND DARKNESS.  PAUL EHRLICH WENT SO FAR AS TO TELL A  RADIO AUDIENCE  TO EXPECT "REPORTS OF PEOPLE  DYING OF THIRST ON THE EQUATOR BECAUSE ALL THE WATER IS FROZEN."


BUT WHILE THIS GRIM PROPHECY'S AUTHORS  NOW INSIST   THEIR   

"1980s predictions of nuclear winter effects were, if anything, underestimates."
-- Physics Today December 2008                                                                            THEY NOTE  ELSEWHERE
"We do not conduct detailed new studies of the smoke and dust emissions from nuclear attacks here. Rather, we chose emissions based on previous studies so as to make our results comparable to them."  - Journal of Geophysical Research  July 2007 
SO HOW DO THE OLD AND NEW MODELS
ACTUALLY LOOK WHEN COMPARED ?

"Nuclear Winter" was less an hypothesis than a media campaign-- it debuted  not in Science , as many assume but Parade magazine, where peer review posed no problem, as Carl Sagan was its  Science Editor.
The surviving  TTAPS autors, Turco, Toon and Ackerman seem to  be in denial- progress  in  climate science  has not  sustained the vision of  subzero cold and global night they advertised in the 1980's. To keep their apocalyptic factoid alive, they have rejected the empirical studies that gutted the guesstimates  on which the 1983 model relied, and resorted to even more unrealistic assumptions, like smoke particles that hang in the air for a decade.  Never mind the  residence time of  micrometeorite debris, just move along.
The effort to revive the expression  by  defining it down  to fit the data recalls another authority who met with a crack-up:
“When I use a word,’ Humpty Dumpty said in rather a scornful tone, ‘it means just what I choose it to mean — neither more nor less.’
’The question is,’ said Alice, ‘whether you can make words mean so many different things.’
’The question is,’ said Humpty Dumpty, ‘which is to be master — that’s all.”

In 1983, the words  "nuclear winter"  were supposed to mean a global deep freeze dark enough to scare a Siberian Commisar into signing a peace treaty-  the  severity of winter weather, as reflected in heating bills, is reckoned in terms of time and temperature , and at 22,000 degree-days the TTAPS worst case 'winter' was harsher than any place on Earth. 

While winter in Washington DC adds up  to 5,000 degree-days The new 'winters' from the old modelers weigh in at under 1,000, and  span  roughly the range from Savannah to Havana.

But one thing hasn't changed since the days of the Cold War: even if the end of the world isn't what it used to be , strategic policy remains too important to be predicated on mythology.