Text 19227, 71 rader
Skriven 2014-11-10 14:48:41 av Michiel van der Vlist (2:280/5555)
     Kommentar till en text av Ward Dossche (2:292/854)
Ärende: Life Under the Democr
=============================
Hello Ward,

On Monday November 10 2014 09:36, you wrote to me:

 WD> Michiel,

 Mv>> If the average remperature of the oceans rises by 1.5 degree yoy
 Mv>> will have your one meter rise. without any ice melting. Basic
 Mv>> physics, denial is futile.

 WD> OK, but that is not a linear process.

Indeed it is not. But it is a good enough aproximation for the problem at hand.
Which was to falsify your claim that ther is not enough water om earth to let
the sea level rise by one meter.

 WD> If the water temperature were rise by 15øC (we're talking Celsius
 WD> here, right?) there will "not" be a 10 meter water level rise.

Indeed, not exactly 10 meters. A bit more in fact.

 WD> That expansion co‰fficient which you explained to me, and I have no
 WD> reason to doubt it, certainly is not a constant.

Indeed it is not a constant. Above 4 degree - yes, Celsuis - the expansion
co‰fficient GOES UP. So the thermal expansion with a 15 degree rise will be a
bit more than ten times that for a 1.5 degree rise. Not very much, not enough
to matter for this argument, but it certainly will not be less.

 Mv>> For a one meter rise, the spreading is neglegible, most land is
 Mv>> more than one meter above sea level. Even in the most extreme case
 Mv>> of rise, 2/3 of the globe alraedy is water so at most 1/3 can be
 Mv>> added, so the reduction in rise by spreading will be at most 30%.

 WD> That in itself is a whole lot.

Hardly. It is less than a factor two. Mind you the extreme case only applies
when ALL of the earth - including Mount Everest - is covered with water. This
kind of argument is often used to set an upper bound. In this case ity shows
that even in the absurd case of all the earth flooding the effect does not
exceed 30%.

For a mere 100 meter rise, the percentage is much lower. I do not have an exact
figure, my estimate is less than five percent.

Whe dealing with these matters one has to learn to deal with "order or
magnitude", "Less than a factor two", and the like. Indeed, we do not know
exactly how much ice there is on Greenland. But we have a fair estimate which
will not be off by a factor two. But the effect of that ice melting is an order
of magnitude latger than that of termal expansion. So if termal expansio alone
is enogh to flood Antwerp, the melting of the Greenland ice certainly will. And
even more certain will be that the Antartic ice cap will. Because that effect
is another order of magnitude larger.

 Mv>> WD> Plus, more water enhances cooling

 Mv>> What makes you think that?

 WD> People I worked with from TH Delft.

Ah, argument by authortity...  Hmmm... it so happens that I also worked at TH
Delft. And it wasn't as a cleaner. Now what?

Sorry Ward, calling on authority isn't good enough. You have to present their
line of arguments, not their line of titles.


Cheers, Michiel

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