Must be close to modern-day high?

http://nsidc.org/data/seaice_index/i...timeseries.png


--
Brian Wakem

On Tue, 22 Sep 2009 08:24:38 +0100, Brian Wakem wrote:

Must be close to modern-day high?

What that graph doesn't give you though is any sense of year-to-year
variance, which I suspect is quite marked. The 79-00 average would
have been better plotted as an envelope with say +/-2SD shown above
and below the average line. I'm guessing that the 2009 data wouldn't
then stick out as noticeably (if indeed a 2-3% deviation is
significant anyway).

JGD

On Sep 22, 8:31*am, John Dann wrote:
On Tue, 22 Sep 2009 08:24:38 +0100, Brian Wakem wrote:
Must be close to modern-day high?

What that graph doesn't give you though is any sense of year-to-year
variance, which I suspect is quite marked. The 79-00 average would
have been better plotted as an envelope with say +/-2SD shown above
and below the average line. I'm guessing that the 2009 data wouldn't
then stick out as noticeably (if indeed a 2-3% deviation is
significant anyway).

JGD

True, John. This graph from Cryosphere (I know it's area and not
extent, but at these timescales, it won't make a lot of difference)
shows that well.

http://arctic.atmos.uiuc.edu/cryosph...anom.south.jpg

The present anomaly from the satellite era mean is presently higher
than average, but nothing especially high. I doubt whether it is more
than 1SD away from the mean and it is certainly not 2SD, which would
include 95% of the population (in this case all the measurements of
Antarctic Sea ice area from the graph) and would be regarded as
statistically significant. 1SD away from the mean would only include
68% of the measurements, which would mean that 32% of the time
(probably at least 32%) the anomaly would have been higher in the
past.

I've been talking about trends a lot with respect to Arctic sea ice
and the 30-year trend there shows a marked decline. Presently, that is
well below the 5% significance level and it has been for all the
recent summers. Like 2007 and 2008, the 2009 summer low is probably 3
SD below the mean, which would make it significant at the 1% (or 99%)
significance level.

I'd ask anyone who is interested to try sorting any trend from the 30-
year changes shown on that cryosphere graph for Antarctic sea ice. The
present levels are certainly not statistically significant. Then, if
you wonder why there is no trend, do just a little bit of research to
see why there may not be. Most scientists - and most contributers on
here - are well aware of the reasons.

On Tue, 22 Sep 2009 01:11:10 -0700 (PDT), Dawlish
wrote:

I doubt whether it is more
than 1SD away from the mean and it is certainly not 2SD, which would
include 95% of the population (in this case all the measurements of
Antarctic Sea ice area from the graph) and would be regarded as
statistically significant.

The only slight caveat to that is the usual one of knowing/estimating
what the underlying distribution of the population might be. Perhaps
it might be at least tolerably close to a normal distribution, but
maybe someone has done some checks.

Personally, I was always somehow more comfortable with non-parametric
stats for this sort of study - again I imagine that someone might have
used non-parametric methods to look at eg ice data - but I really
can't remember too much about how to apply such methods.

JGD

On Sep 22, 10:03*am, John Dann wrote:
On Tue, 22 Sep 2009 01:11:10 -0700 (PDT), Dawlish
wrote:

I doubt whether it is more
than 1SD away from the mean and it is certainly not 2SD, which would
include 95% of the population (in this case all the measurements of
Antarctic Sea ice area from the graph) and would be regarded as
statistically significant.

The only slight caveat to that is the usual one of knowing/estimating
what the underlying distribution of the population might be. Perhaps
it might be at least tolerably close to a normal distribution, but
maybe someone has done some checks.

Yes, agreed.

Personally, I was always somehow more comfortable with non-parametric
stats for this sort of study - again I imagine that someone might have
used non-parametric methods to look at eg ice data - but I really
can't remember too much about how to apply such methods.

Me too. I did love the stats lectures at Reading.....................

On 22 Sep, 11:46, Dawlish wrote:
On Sep 22, 10:03*am, John Dann wrote:

On Tue, 22 Sep 2009 01:11:10 -0700 (PDT), Dawlish
wrote:

I doubt whether it is more
than 1SD away from the mean and it is certainly not 2SD, which would
include 95% of the population (in this case all the measurements of
Antarctic Sea ice area from the graph) and would be regarded as
statistically significant.

The only slight caveat to that is the usual one of knowing/estimating
what the underlying distribution of the population might be. Perhaps
it might be at least tolerably close to a normal distribution, but
maybe someone has done some checks.

Yes, agreed.

Personally, I was always somehow more comfortable with non-parametric
stats for this sort of study - again I imagine that someone might have
used non-parametric methods to look at eg ice data - but I really
can't remember too much about how to apply such methods.

Me too. I did love the stats lectures at Reading.....................

Whichever way you look at it, it looks as if there is more ice than
there has been, both in the Arctic, and in Antarctica. Not a lot, I
grant you, but it is on the increase. So I wonder how long the AGW
lobby will continue to howl that "the ice is melting and we're all
doomed"? A slight increase in temperature or a reduction in sea ice,
and the AGW alarmists would say "told you so", but a slight change in
the other direction and it's just a "blip" or of no consequence. I
think on balance it's going to get cooler, and I'm not alone in that
belief.

CK

On Sep 22, 5:36*pm, Natsman wrote:
On 22 Sep, 11:46, Dawlish wrote:





On Sep 22, 10:03*am, John Dann wrote:

On Tue, 22 Sep 2009 01:11:10 -0700 (PDT), Dawlish
wrote:

I doubt whether it is more
than 1SD away from the mean and it is certainly not 2SD, which would
include 95% of the population (in this case all the measurements of
Antarctic Sea ice area from the graph) and would be regarded as
statistically significant.

The only slight caveat to that is the usual one of knowing/estimating
what the underlying distribution of the population might be. Perhaps
it might be at least tolerably close to a normal distribution, but
maybe someone has done some checks.

Yes, agreed.

Personally, I was always somehow more comfortable with non-parametric
stats for this sort of study - again I imagine that someone might have
used non-parametric methods to look at eg ice data - but I really
can't remember too much about how to apply such methods.

Me too. I did love the stats lectures at Reading.....................

Whichever way you look at it, it looks as if there is more ice than
there has been, both in the Arctic, and in Antarctica. *Not a lot, I
grant you, but it is on the increase. *So I wonder how long the AGW
lobby will continue to howl that "the ice is melting and we're all
doomed"? *A slight increase in *temperature or a reduction in sea ice,
and the AGW alarmists would say "told you so", but a slight change in
the other direction and it's just a "blip" or of no consequence. *I
think on balance it's going to get cooler, and I'm not alone in that
belief.

CK- Hide quoted text -

- Show quoted text -

No, I agree you are not alone Natsman, but the scientists who agree
with you are in a tiny minority and nobody that counts is listening to
them.

Why not read the explanations of trends and deviations from the mean
that I've given on this thread. If you understood what they show,
you'd then realise why I say what I do about Arctic ice being in a
continuing downward trend. Increases, or decreases, in Antarctic ice,
especially in winter, mean very little, if you are trying use this to
make a case for global cooling, like Lawrence, you are barking up the
wrong tree.

"Dawlish" wrote in message
...
On Sep 22, 5:36 pm, Natsman wrote:
On 22 Sep, 11:46, Dawlish wrote:





On Sep 22, 10:03 am, John Dann wrote:

On Tue, 22 Sep 2009 01:11:10 -0700 (PDT), Dawlish
wrote:

I doubt whether it is more
than 1SD away from the mean and it is certainly not 2SD, which would
include 95% of the population (in this case all the measurements of
Antarctic Sea ice area from the graph) and would be regarded as
statistically significant.

The only slight caveat to that is the usual one of knowing/estimating
what the underlying distribution of the population might be. Perhaps
it might be at least tolerably close to a normal distribution, but
maybe someone has done some checks.

Yes, agreed.

Personally, I was always somehow more comfortable with non-parametric
stats for this sort of study - again I imagine that someone might have
used non-parametric methods to look at eg ice data - but I really
can't remember too much about how to apply such methods.

Me too. I did love the stats lectures at Reading.....................

Whichever way you look at it, it looks as if there is more ice than
there has been, both in the Arctic, and in Antarctica. Not a lot, I
grant you, but it is on the increase. So I wonder how long the AGW
lobby will continue to howl that "the ice is melting and we're all
doomed"? A slight increase in temperature or a reduction in sea ice,
and the AGW alarmists would say "told you so", but a slight change in
the other direction and it's just a "blip" or of no consequence. I
think on balance it's going to get cooler, and I'm not alone in that
belief.

CK- Hide quoted text -

- Show quoted text -

No, I agree you are not alone Natsman, but the scientists who agree
with you are in a tiny minority and nobody that counts is listening to
them.

Why not read the explanations of trends and deviations from the mean
that I've given on this thread. If you understood what they show,
you'd then realise why I say what I do about Arctic ice being in a
continuing downward trend. Increases, or decreases, in Antarctic ice,
especially in winter, mean very little, if you are trying use this to
make a case for global cooling, like Lawrence, you are barking up the
wrong tree.


You do make me laugh Paul, why even the warmist are conceding (due to
reality sinking the models) that we are heading for a cooling period with of
course AGW to return in earnest 10-16 years down the line.

What ever next , deferred warming?

"Lawrence Jenkins" wrote in message
news:00b3eece$0$23838

You do make me laugh Paul, why even the warmist are conceding (due to
reality sinking the models) that we are heading for a cooling period with
of course AGW to return in earnest 10-16 years down the line.

What ever next , deferred warming?


There is often talk of "feedback" mechanisms and "tipping points" in the
Global Warming Industry.
Well, they are there for sure and will show themselves in a manner not quite
expected
by those in it's employment.

At some point soon the penny will drop. Some high priest of AGW will notice
that it is they who have their neck
in the noose and get a chill of realisation down their spine.

The tone will change abruptly. A tipping point will be reached. The big
money will go elsewhere. The whole house of cards will tumble at a
frightening speed. Heads will roll.

And I'll remind y'all that I told you so.

Tick Tock, Tick Tock.......

Paul

On Sep 22, 10:16*pm, "Paulus" wrote:
"Lawrence Jenkins" wrote in message

news:00b3eece$0$23838



You do make me laugh Paul, why even the warmist are conceding (due to
reality sinking the models) that we are heading for a cooling period with
of course AGW to return in earnest 10-16 years down the line.

What ever next , deferred warming?

There is often talk of "feedback" mechanisms and "tipping points" in the
Global Warming Industry.
Well, they are there for sure and will show themselves in a manner not quite
expected
by those in it's employment.

At some point soon the penny will drop. Some high priest of AGW will notice
that it is they who have their neck
in the noose and get a chill of realisation down their spine.

The tone *will* change abruptly. A tipping point *will* be reached. The big
money will go elsewhere. The whole house of cards *will* tumble at a
frightening speed. Heads will roll.

And I'll remind y'all that *I told you so*.

Tick Tock, Tick Tock.......

Paul

Lots of *wills* in there Paul!

Unfortunately for denialists like yourself, the world is likely to be
moving further towards a lower carbon economy by then, as GW is very
likely to be continuing to make its effects felt and you are unlikely
to be still posting about the end of GW Paul, having to suffer a few
deprivations along the way to enable your government to move, with
others, towards that lower carbon future!

The denialists just don't understand trends (well, actually, they deny
them!) and back the climate long-shot all the time; feeling that so
many scientists are wrong and their opinions are right. Of course
there's a chance you may be right - any sceptic like myself would
concede that - but your language of "will" happen, given the present
situation, is a long way removed from the present scientific consensus
and is thus likely to be wrong. It's the *will* word that I and many
others find grating. You really would like the world to do nothing,
just so that if the long-shot comes in you'll be able to say "I told
you so". It is much more likely that the denialists will have settled
on another scientific long-shot and will have quietly forgotten that
they campaigned to prevent the world trying to safeguard its future.

Again, I'd implore you to read and understand the stats about Arctic
and Antarctic ice (the thread title). You won't want to, I know,
because they tell a story which blows holes in your denialism.