Visible: The beginnings of a European freeze driven by... global warming!

Nov 30 05:49 UTC 1999

BBC News Online: Sci/Tech (annotations in [[brackets]])
 
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                Thursday, 25 November, 1999, 08:48 GMT 
                Ocean drift disruption may chill Europe
        Scientists have found evidence that the Atlantic Ocean current
         which gives Europe its mild climate is being disrupted. 
 
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        "This is the largest change we have seen in the last 100 years" -
                        Dr Bill Turrell 
 
If it stopped, then the temperatures in western Europe would plunge by
five degrees Celsius, creating bitter winters.  The culprit for the
changes could, ironically, be global warming. 
 
The current, called the North Atlantic Drift, brings warm water
northwards from the Gulf Stream.  It is being disrupted by a growing
amount of freshwater entering the Arctic Ocean, reports New Scientist
magazine. 
 
[[Freshwater, such as you'd get from the melting of the Arctic icepack.
The ice over the Arctic sea has become quite a bit thinner, and the
season it is totally frozen is already shortening to the point that
polar bears are in danger of losing their food supply.]]
 
This increase is a result of changes attributed to climate change and
possibly global warming:  melting ice, increased rainfall and changing
wind patterns. 
 
                Global conveyor belt
 
The North Atlantic Drift is part of a global conveyor belt that brings
warm, surface water north from the Gulf of Mexico and sends cold, deep
water back. 
 
[[Saline water is the other half of the conveyor; the water which falls
has to be relatively dense, and the additional salt is the key.  The
Gulf Stream currents from the Carribean apparently supply the salt.]]
 
The belt is driven by two "pumps", one in the Greenland Sea and one in
the Labrador Sea, where the surface water cools, becomes denser, sinks
and then returns south. 
 
A computer model developed by Stefan Rahmstorf of the Potsdam Institute
in Germany has already suggested that global warming could turn off the
North Atlantic Drift but there has been no evidence that this is really
happening.   [[Yet.]]
 
However, several teams are now reporting changes which fit in with the
model's predictions.  Bill Turrell, leader of the Ocean Climate Group
at the Scottish Executive's Marine Laboratory in Aberdeen, analysed
more than 17,000 measurements of seawater salinity between Shetland and
the Faroe Islands collected since 1893. 
 
[[This can be added to the thousands of temperature measurements in
zones which have not experienced changes in land usage patterns, but
have nevertheless seen increased averages.  The salinity data is
another set of facts for the warming denialists to deny.]]
 
Dr Turrell found that in each of the past two decades the salinity of
the deep water flowing south has dropped by 0.01g of salt per kg of
seawater.  So its density has probably also decreased. 
 
[["Probably", because you can't measure the in-situ temperature of a
slug of 1893 seawater in a bottle in a museum.  But very suggestive.]]
 
"This is the largest change we have seen in the outflow in the last
100 years," says Dr Turrell.  "It is consistent with models showing the
stopping of the pump and the conveyor belt." 
 
This contrasts with the situation in the 1950s when the salinity of
the outflow was so stable it was used to calibrate equipment. 
 
[[From calibration-quality to indicator of catastrophe.  Isn't that
enough of a wake-up call for you?]]
 
                Warm water 
 
His findings are echoed by work at the Fisheries Laboratory of the
Faroes.  Monitoring conducted there suggests the deep-water outflow
through the channel to the southwest of the islands is getting warmer. 
 
[[Both warmer and less saline.  Cold and salt are the engines which
drive the current.  What happens to the east coast of the USA if the
Gulf Stream goes away?]]
 
In a study yet to be published, Bogi Hansen of the lab says the level
at which water is at -0.5C sank by 60 metres between 1988 and 1997. 
 
Svein Osterhus of the University of Bergen in Norway has also
discovered that a deep-sea current closer to the Arctic has gone into
reverse.  In 1982 and 1983, deep water flowed southwards from the
Greenland Sea into the Norwegian Sea at 10 centimetres per second. But
in 1992 and 1993, the water was flowing at one centimetre per second 
in the opposite direction. 
 
This indicates that the Greenland Sea pump "has been dramatically
reduced in power", says Dr Xsterhus. 
 
[[Note, this is the third independent measurement indicating the
same thing.  One is a glitch.  Two is a split decision.  Three is
unanimous.  It is time to be afraid.]]
 
"Any evidence that changes in ocean currents are starting to occur is
very important," says computer modeller Dr Rahmstorf.  "The freshening
and warming of the deep water flowing back into the Atlantic is
consistent with global warming but could also have natural causes." 
 
[["Could"... but do you want to bet your climate on it?]]

response 2 of 109:

Nov 30 17:07 UTC 1999

Another hit Don Quixote!  Frankly, computer models are simply prejudiced
by the assumptions that the programmer makes and the limited actual raw
data on the long term cycles of the earth, that I hardly think mandifest
themselves within the 170 year sample data.  We can only guess, maybe, global
temperature rise caused by human action might possibly in the slightest way 
be responsible for shifts in patterns hundreds of millions of years old.

response 4 of 109:

Nov 30 19:04 UTC 1999

  Obviously one cannot predict exactly what will happen without both complete
  knowledge about the current state and understanding of how future states
  arise from the present state.

  However, the fact that our knowledge is incomplete doesn't mean that we are
  totally unable to make useful predictions.  If today is 80 degrees (F) it
  doesn't necessarily mean that it won't snow tomorrow, but one can conclude
  that with a fairly high degree of likelihood and a rational person would
  make their plans accordingly..

response 6 of 109:

Nov 30 22:07 UTC 1999

However, extrapolation of the results and declaring that one basic factor
might be responsible (which is what the article above does do), without
knowledge of what the planet "HAS DONE" with such conditions, appears to me
to be completely biased and presumptive.  Terms like "possibly" and "could"
taint the subject severely, and the poster's last line clearly exhibits
the bias.  The article itself pretends to offer a weak "natural cause"
theory, but the rest of the article is pretty blatant in making dire 
preditions from the inferrence of global warming.

Everyone knows that in these political times, global warming is a buzz word
meaning "human caused change", otherwise "naturally occuring" would
be guilty until proven innocent.

response 8 of 109:

Dec 1 03:25 UTC 1999

I don't live life on the edge.  I don't live life afraid that my next move
will be my last.  If I did, I'd be frozen in place.  

response 10 of 109:

Dec 1 04:43 UTC 1999

Re #8: And what's that supposed to mean?  That it's somehow cowardly to
think about what effect we might be having on the future?

Let me explain again.  We have some very convincing evidence that we're
causing something that will result in major problems for us. We can't be
absolutely sure that it's us, but it seems very likely. 

Now, don't you think maybe we should change what we're deing to try to
prevent this?  The risks are too great to ignore, and if we decide to 'wait
and see' it'll be too late.

response 12 of 109:

Dec 1 06:33 UTC 1999

That must mean that you are really stocking up on ice cubes in preparation
for global warming. 

response 14 of 109:

Dec 1 12:31 UTC 1999

Thinking about things like global warming is not good because otherwise
we might feel guilty about our egocentric, excessive behavior ;-)

response 16 of 109:

Dec 1 19:46 UTC 1999

Exactly -- if we'd started seriously doing something about Y2K problems back
in the 80's, we wouldn't be scrambling now.  Good analogy, bdh.

response 18 of 109:

Dec 1 23:43 UTC 1999

(Fine.  So imagine 'em a while down the line saying "Surely everyone has had
since at least, oh, 1990 to think about this atmosphere thing")

response 20 of 109:

Dec 2 13:38 UTC 1999

"All those other problems will still be with us" is very true.  We differ
on the cause and effect.  I continue to contend that global changes, whether
they are temperature increases or decreases are within perfectly reasonable
tolerance levels for our globe.  Weather pattern changes are also quite
a fact of life on this planet.  

Industrial age thermadynamics are not going to make the earth
uninhabitable.  Just as the earth itself will go through pattern changes,
so too will it be changed by man.  At some point, man may be able to
control the weather.  Would this be a "BAD THING (tm)".  Certainly it
would not be what the earth itself would provide.

In any case, I see this discussion as "oh my god, we're changing our
environment and it will kill us!"  Trying to bring a little sanity to
this discussion, my contention is that any changes will be tolerable
exchange for our continued development of and on this planet.  Perserving
our atmospheric condition is a lost cause.  Not because we are playing
with fire, but because it's going to change of it's own accord anyway.
Until we get some real environmental controls, we're just wringing our
hands and fretting about the future in a waste of personal energy.

response 22 of 109:

Dec 2 18:40 UTC 1999

  re #20:  perhaps the more hysterical elements are screaming "we're
  changing our atmosphere and it will kill us!" but it would be better
  to listen to the experts in the field who are almost all telling us
  "we're changing our atmosphere and it's going to have unpredictable
  consequences, most of which are likely to be unpleasant."

  Perhaps the death-and-doom-sayers get more attention because they're
  louder and their message is more dire but the message of the experts
  is clear enough -- that conditions *are* changing and that results
  will follow which *will* be "BAD THINGs (tm)"

  Yes, we'll still be able to live on the planet if even the most dire
  predictions of responsible scientists turn out to be the case, but
  the planet may not be able to support nearly so many of us..

response 24 of 109:

Dec 2 20:50 UTC 1999

Has anyone speculated on what effect global warming might have on the Great
Lakes?  As some of you may be aware, Lake Michigan and Lake Huron are
currently about two *feet* below normal levels, and Superior is down six
inches.  I think this is in the range of normal variation, but I'm curious
what the future may hold.