On 19/01/2019 13:02, JGD wrote:
On 18/01/2019 19:43, N_Cook wrote:

I hope you can admit , that to reach such IPCC predictions, there must
be some sort of up-curve at some point.

I'm sure that few in the scientific community believe that the rise in
sea level is _not_ going to accelerate in the coming years. The question
is how you estimate or express that likely rise and its magnitude. My
point is that the only credible way of doing so is by developing a
numerical model and not by blind curve-fitting.

Oceanography is not my field but, unsurprisingly, it looks like several
such models are well under way. Here's the results of one for instance:

https://www.nature.com/articles/s41467-018-02985-8

(I'm slightly surprised that a Nature article seems freely accessible,
but I had no trouble reading it and there even seems to be a
donwloadable PDF.)


Detail of the Jason-3 revisioning, perhaps the AGW lot can get to the
bottom of it.
http://diverse.4mg.com/aviso25may_ma...01_overlay.jpg

01 Sep Aviso outputed curve converted to green and overlaid on the
earlier 25 May Aviso output.
Not perfect alignment as change of x and y scales and not fine enough,
discrete changes in scaling only possible in my graphics packages.
Note near coincidence of the gradients , but main point is the peak in
mid 2016 (green below blue) and peak in mid 2017 (green above blue), is
impossible to resolve even taking the scaling the other side of an ideal
superimposition.

Presumably swept under the carpet in the phrase on the Aviso site
"- for scientific and statistics reasons, period under 5 years are not
significant."

There is no "business as usual" Trump-land curve in that Nature paper,
for the early 21C situation, like on here

http://www.realclimate.org/index.php...omment-page-5/

Gives such a projection as 52cm for 2050 and 98cm for 2100
From that Nature paper ,taking 2035 peak net-zero CO2 plot as a close
stand-in for business-as-usual and the state of early 21C,
gives 22cm for 2050 and 55cm for 2100.
My analysis ,projecting on from the Jason data over one cycle of up and
down trend and best curve-fitting to the 2003 to 2018 data, from 2000 =0 cm.
Minimum 22cm rise to 2050 and 49cm for 2100
Maximum 24cm rise to 2050 and 61cm for 2100
so far , nearer the mor ebenign "2035" scenario.
Whichever way you look at these projections, a rise of the yearly rate
of global sea level rise, from the non Jason or projection fitting
linear 3.3/3.4 mm per year. I don't trust the Saral/Attica project as
its "calibrated" against tide-gauges which go up and down with
geological rates of the mm/year rate much as sea level rates, via
isostatic rebound, tectonic plate movement, human-led local water
abstraction under the tide-gauges etc
I wonder how much of this projection v. reality I will live to witness.