Hi Mike and Alan,
I think we are on the same side when it comes to what matters. Are we
not all fighting for a better future for humanity on this planet we
all share? And doesn't this involve doing something to prevent the
situation getting a lot worse in the Arctic, even when there is
disagreement between models and observations over just how bad the
situation has become and how quickly the situation is deteriorating?
Surely the international scientific community should pull together and
agree on action to improve the situation which has a chance of
success? Surely some kind of interim intervention to restore Arctic
albedo is required, even if only on a precautionary principle if you
think the most optimistic models are correct. And shouldn't we
prepare for intervention as quickly as possible to give ourselves the
greatest chance of successful deployment, while continuing research
and developing better models to optimise that deployment? And isn't
preparation for deployment justified even if it doesn't prove necessary?
Preparation need not take years. There was a discussion on the Ebola
outbreak on the radio this morning. They said how the procedure for
drug testing which would normally take years had been cut down to six
weeks - but even that was too long to save many lives.
There has been a huge antagonism to geoengineering built up over the
years, so that most scientists are now against it. But our job is to
recommend what is best for humanity. We need to use some
geoengineering techniques for a limited period to get the planet back
on course - reversing climate change and restoring the climate to
Holocene-like conditions. We must not fail to give good advice just
because of public sentiment against geoengineering.
Cheers, John
On Sun, Nov 27, 2016 at 7:32 PM, Michael MacCracken
<[email protected] <mailto:[email protected]>> wrote:
Hi Alan--I don't disagree that there are problems with models,
just there have been with various types of observations that have
to get resolved (e.g., the Microwave Sounding Unit time series,
ocean observations as types of instruments changed, etc.). And the
full set of observations can also be incomplete, not accounting
for all that may matter. What science needs to do is work out
why--not believing either in some absolute sense.
On the Arctic situation, I was just noting the obvious, namely
that if you drive even perfect models while not accounting for
some particular forcing, that could well be a cause of/contributor
to the disagreement between results of model simulations for ice
volume and extent and observations--it is not always the physics
that is the problem.
I'd generalize your statement that history (here meaning of
scientific discovery) has not looked favourable on those who
ignore the observations, however erratic or unreliable, to suggest
that those who carefully seek to understand the differences
between available observations and available models (theory),
accepting neither without question, have been those who have most
advanced the science (and in so doing they must look at everything
skeptically and then also look for what we may not even be
considering).
Best, Mike
On 11/27/16 1:54 PM, Alan Gadian wrote:
Mike,
Sorry for the delay .. in India.
I am afraid I am someone on the "other side" in that I use NWP
and climate models for my living. Thus I can speak as someone
who has used them a lot!
There are good things about climate models as well as bad
things. The fear I have is that the whole of the IPCC is based
on climate models, and that is the issue. There are huge
differences between the poles, and these are largely ignored.
There are other processes which are not replicated in
climate models. Why a double ITCZ? Why little Indian monsoon.
One can explain these features ...
I note the papers, but I am afraid, whether it is 70km
mountains on Venus (as proposed by NASA) history has not
looked favourably on those who ignore the observations,
however erratic / unreliable.
Thanks for your comments
Alan
On Wed, 23 Nov 2016, Michael MacCracken wrote:
Dear Alan--When observationalists are clear the
observations of ice thinning and retreat are
right, and the modelers are insisting that the physics is
the model is properly constructed
and correct, then, if there are inconsistencies between
the two, what needs to be looked at
very carefully is the forcing, or more specifically, the
changes in the forcing over time.
Specifically, there have been changes over time in the
sulfate and black carbon forcing that
affect the solar radiation budget and also cloud albedo,
and there have been changes in the
tropospheric ozone concentration (as well of the
greenhouse gases, which need to be treated
specifically and not using CO2e). I'd suggest that all it
would take are some relatively
modest problems in some of these forcings as the region
has gone through the issue of Arctic
springtime haze and the its "clean up" as SO2 emissions in
Europe and North America grew and
then cleaned up much of the SO2 emissions, as the black
carbon loadings changed as growth of
diesel emissions of black carbon changed and were somewhat
reduced, and then as China has
grown. Calculations in Navarro et al, 2016 make clear that
changes in forcing can influence
the Arctic. I'd just suggest that a hypothesis that I
think likely needs some exploration is
that it is the time history of the forcings that could
explain the difference between the
observations and the models, and that it might be more
productive to look at this alternative
hypothesis as a way of explaining their differences.
I'd also note that I suggest this as only one alternative
hypothesis--there may well be
others. In any case, I'd suggest finding some possible
explanation(s) for the differences and
to get working on reconciling and understanding the
reasons for the differences--which is
what science generally aims at doing rather than simply
blaming the other side.
Best, Mike MacCracken
On 11/23/16 1:50 PM, Alan Gadian wrote:
Reto and Peter,
ECMWF is the best forecast model in the world. If you had
attended the change of
directorship last Spring, you would have heard them say
that the ice model predictions
( and they have the HIGHEST resolution forecasting model)
are terrible, do not predict
changes and have little connection with reality. My
climate model has taken 250 days
on 12,000 cray cores and I only achieve 20km resolution.
( I estimate I used about 2
million dollars of electricity in the end, as some of the
model is at 2-3km resolution.
It has possibly been one of the biggest projects on ARCHER.
ECMWF can run globally at 2-4km resolution. How is it
also that Martin Miller , who
masterminded much of the ECMWF model said of AR5 , that
the clouds were so badly
predicted that the radiative balance is not correct, and
the climate models could not
be trusted for clouds and radiation? He was one of the
worlds best experts,but
ignored.
Also then, How is it that then the climate models can do
so much better than the best
weather prediction models in the world? When the data
evidence of the HUGE changes in
ice volume and extent, are so apparent, so much so that by
the time AR5 went to press ,
six months after writing, the ar5 ice extent predictions
were outside the predicted
range for the worst scenario, how can the ar5 community
still try to sell the story?
Maybe Trump took his lead from the climate modellors?
I have had endless arguments with Piers Forster , another
lead author on ar5 about
this. scientists who know about modelling the weather
have been ignored. You do not
get papers published which day that models are wrong, only
when you say how great they
are.
In essence ,after AR3, it has become a gravy train for
academic careers based largely
on CXXP models. In a short time these models will be
shown to be catestrophically
wrong, and all that is done is to pillory those who try to
point out the true science.
Regards
Alan.
T --- Alan Gadian, NCAS, UK. Email: [email protected]
<mailto:[email protected]> & [email protected]
<mailto:[email protected]>
Tel: +44 / 0 775 451 9009
<tel:%2B44%20%2F%200%20%20775%20451%209009>
T ---
On 23 Nov 2016, at 15:32, P. Wadhams <[email protected]
<mailto:[email protected]>> wrote:
Dear Dr Knutti, I would like to intervene in this
seemingly interminable
thread to draw attention to errors which you have
made when you mention my
work.
1. " But the natural variability is very large (e.g.
Kay 2011,
Swart 2015, Screen 2013, 2016). There is no
reason why short
term trends could simply be extrapolated, and
the predictions
by Peter Wadhams of sea ice disappearing by
today have not
happened so far"
a) I completely agree that natural variability is
very large and stress
this in my book "A Farewell to Ice" which I suspect
you have not read. In
the book I stress that it is the TREND which is
rapidly downwards towards
zero, not that every successive year features a
monotonic decrease in
summer ice volume. And, despite the newspaper
reports which seems to
constitute your reading matter on my work, I do NOT
forecast that the ice
volume will go to zero in a specific year (like this
year), only that it
will go to zero in a very small window of years (of
which this year forms
one) as opposed to the decades which are still
forecast by the worst of the
current models. You might also care to glance at the
current NSIDC charts
for ice volume (Arctic and Antarctic) which show an
extraordinary turndown
since September suggesting that the co-operative
collapse which I have long
projected through my thickness measurements is now
happening. b) Why can't
short term trends be extrapolated? Firstly, they are
not short term - they
date back to the 1980s when observations began. And
secondly, please name
the magical effect which will cause the trend to
become invalid and the ice
volume to pick up again.
2. > Maybe the models are missing something, but
it's just as plausible
(and
in most scientist's view more likely) that the
models are
largely consistent with observations within
natural
variability.
Your idea of "most scientists" is an odd one. When
the observations show a
rapid declining trend leading to zero very soon, how
can models (which
predict decades of continued summer sea ice) be
consistent with these
observations? They are simply not consistent, and it
is clear that by "most
scientists" you mean "many modellers", some of whom
have never seen sea
ice.
3. I'm not
downplaying the strong changes in the Arctic,
but the science
suggests a fairly linear (and reversible)
relationship between
Arctic sea ice and temperature with large
variability
superimposed. In my view they do not support a
"death spiral".
Well, it's obvious that there is a linear
relationship between air
temperature history and sea ice thickness. The
"degree days of cold"
analysis dates back to the 1950s and was amplified
by Maykut and
Untersteiner's analysis in 1971. But if air
temperature is increasing
rapidly, as it is, then thickness will decline just
as rapidly, leading to
a period in summer with zero thickness, in other
words, a "death spiral"
QED.
To paraphrase Captain Scott, I don't think I need
say more,
Best wishes
Peter Wadhams
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