Merged Recent climate observations disagreement with projections

BenBurch said:
You appear to be absolutely ignorant of it...
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Ignorant of the nuances of pseudo science?

Still maintain you roll that average over that autocorrelated data?

How about applying smoothing procedures to ...

  1. ice core data?
  2. Sediment data?
  3. Isotope data?
  4. Tree ring data?
 
BenBurch said:
You appear to be absolutely ignorant of it...
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Why are you so quick to jump to the insult?

It is as I pointed out. If you had 60 years of data and wanted to analyse the stability of any trend, e.g. Has the trend increased, stayed the same, decreased, then you would really only have en extremely limited amount of data (after allowing for degrees of freedom) with which to work. You could:

  • Use independent time frames for comparison to maximise your degrees of freedom. Noting that the length of
  • Use many more rolling time frames, but with massively reduced dregrees of freedom.

In effect, the statistics of the problem is such that you need a long time series to test for significance of any measured trend. And you need a number of such long term series that are sufficiently independent of one another to allow comparison between periods with sufficient statistical power.

This is alll germaine to the problem at hand and the OP. What does the data over recent decade(s) tell us about the trend complard with that witnessed over longer or elarier periods?
 
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Geckko said:
Why are you so quick to jump to the insult?

It is as I pointed out. If you had 60 years of data and wanted to analyse the stability of any trend, e.g. Has the trend increased, stayed the same, decreased, then you would really only have en extremely limited amount of data (after allowing for degrees of freedom) with which to work. You could:

  • Use independent time frames for comparison to maximise your degrees of freedom. Noting that the length of
  • Use many more rolling time frames, but with massively reduced dregrees of freedom.
In effect, the statistics of the problem is such that you need a long time series to test for significance of any measured trend. And you need a number of such long term series that are sufficiently independent of one another to allow comparison between periods with sufficient statistical power.

This is alll germaine to the problem at hand and the OP. What does the data over recent decade(s) tell us about the trend complard with that witnessed over longer or elarier periods?
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Longer than a decade or than decades? If the latter how many decades?

The last decade tells us very little about a surface temperature trend because there's too much noise in such a short time series. So we have to consider periods of at least decades, and the general view is that three decades is the minimum. That covers several sun-cycles and rather more El Nino/La Nina cycles, and can reasonably expected to have about average vulcanism. A period that includes only one sun-cycle and one El Nino/La Nina cycle can't tell us anything about climate trends. Unless the trend is particularly dramatic, which the AGW trend isn't.

The last few decades demonstrate a warming trend. That's why glaciers are retreating, permafrost is melting, bio-zones are changing and all the other visible evidence of climate change at a rate and on a scale which has never been observed before.
 
Wasn't an insult, it was an observation.

But let us drop numbers for a moment and look at an analog computer.

As CapelDodger points out, glaciers are retreating.

Ice integrates heat over time. It is an analog computer for warming. If late-summer ice extents stabilize and remain fairly constant, there is no warming or cooling. If late-summer ice extent expands, you have cooling. If it decreases...

And if it does so year after year with few pauses, you have yourself a trend.
 
Ice shelves, multiyear ice cover, mid latitude glaciers and net mass loss for all glaciers are even more telling - and it's accelerated dramatically in the last 3 decades.

Biota changes, upward and poleward, expanded tropics by 200 km....undeniable warming

Head buried in sand to deny otherwise....:garfield:

it's soooo lame to be a denier these days....:rolleyes:
 
BenBurch said:
And if it does so year after year with few pauses, you have yourself a trend.
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True, but Glaciers also retreat due to decreased rainfall…

Geckkos’ point (I believe) was that the scarcity of independent data points makes teasing causation from correlation difficult. Real world indicators (IMHO) make the problem worse not better because they add additional effects not seen in the pure temperature records.

Geckko said:
This is alll germaine to the problem at hand and the OP. What does the data over recent decade(s) tell us about the trend complard with that witnessed over longer or elarier periods?
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All we can say with any degree of confidence is that the warming rate for 1979 to 2009 is somewhat less than for (say) 1969 to 1999. Both periods still show warming though. If the period 1989 to 2019 were to show even more moderation then the significance of this result would rise again.

If you’re asking what precise period of cooling or neutrality would falsify the AGW hypothesis then I don’t have a good answer for you. I suspect if 2019 is no warmer than 2009 then the theory is in some trouble.
 
BenBurch said:
DogB - Rainfall we can accurately measure. Glaciers are retreating even where precipitation has increased.
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Are you claiming because there is a sort of natural running average existant in glacier shrinkage or expansion, we can use them as some sort of measure for the last several decades without the 30 year averaging limitation?
 
BenBurch said:
DogB - Rainfall we can accurately measure. Glaciers are retreating even where precipitation has increased.
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My point was that natural systems respond to multiple inputs - using them as surrogates for simple one dimensional data points such as temperature is fraught.

But you’re right the glaciers are melting (and have been since about 1850).
 
Actually to be perfectly correct, the Glaciers have been melting in a slightly noisy manner since the start of the Holocene, and will continue to do so until the interglacial is over.

Consistency in climate is an illusion formed by limitations in human perception.
 
DogB said:
All we can say with any degree of confidence is that the warming rate for 1979 to 2009 is somewhat less than for (say) 1969 to 1999. Both periods still show warming though. If the period 1989 to 2019 were to show even more moderation then the significance of this result would rise again.

If you’re asking what precise period of cooling or neutrality would falsify the AGW hypothesis then I don’t have a good answer for you. I suspect if 2019 is no warmer than 2009 then the theory is in some trouble.
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Mine was a particularly specific statistical point. It pops up here again.

Note that if you want to investigate the possibility that the trend from 1979-2009 is different from that over the period 1969-1999 there is not quite as much data as there fist appears (i.e. you do not have two 30 year trends, when you account for degrees of freedom).

This is because the trend between 1979-2009 is partly a function of the part of the trend between 1969-1999. In fact 2/3 of it.
 
My point was that natural systems respond to multiple inputs - using them as surrogates for simple one dimensional data points such as temperature is fraught.
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How about you invert that, might cure the the tunnel vision on temperature :rolleyes:....:garfield:

Ice shelves thousands of years old have disappeared in a human lifetime and accelerated loss in the last thirty years....that's NOT "noise"

This is not "noise"
Meancumulativespecificmassbalanceof.jpg


http://climaticidechronicles.org/20...-shows-continuation-of-long-term-melt-trends/
 
Geckko said:
This is because the trend between 1979-2009 is partly a function of the part of the trend between 1969-1999. In fact 2/3 of it.
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Of course - but if you accept the premise that anything less than a thirty year trend isn't trustworthy then you are reduced to using such processes.

Smoothing over thirty year period doesn’t leave us with a whole lot of reliable data.
 
macdoc said:
Ice shelves thousands of years old have disappeared in a human lifetime and accelerated loss in the last thirty years....that's NOT "noise"
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I’ve decided I’m going to tailor my debate style based on that used against me. So my reply to you follows.



Is too!
 
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