General AGW discussion thread

[Stroller]

Thanks Stroller.

Rather than repeat what I just wrote, in response to Jetlack, could you take a look at that post, and have a go at helping me understand?

Also, you seem to be saying that the answer to my question (in the post of mine you're quoting) is that such a case (presentation, narrative, ...) does not exist (if only because people such as yourself have not written it up and published it); is that so? If not, please set me straight.

It may be that my question is not as clear as it could be (I'm still learning the vocabulary), but at its heart it's about a class of hypotheses, the tests they are specifically designed for, and the 'no detectable A in GW' results (that's a shorthand, of course) from those tests. Much of what you write in your post seems to me to be relevant to different hypotheses (though there are, of course, similarities).

It has been difficult to get contrarian papers published, for reasons the leaked emails from the CRU make obvious.

Rather than trying to 'prove a negative', (no A in GW) sceptics have said that the uncertainties are such that the changes in temperature we have seen are within the bounds of natural variability and comparable to previous times before co2 increase. This is why the existence of the medieval warm period has been such a battle ground between sceptics and AGW hypothesis proponents. Good evidence from worldwide sources such as the Greenland ice cores are ignored or marginalised in the literature.

Here is a file containing the individual country records from 1900 before they are processed by CRU's HADcruT2 'code', but after homogenisation by GHCN.
http://strata-sphere.com/blog/wp-con...5_vs_2008b.pdf

As you can see, there are many countries which show little warming over the C20th according to this data. The Russian data in the very bottom graphs only represents 40% of the landmass of Russia, which itself is over 10% of the global landmass. Stations north of 70 degrees which show no warming have been ignored.

To summarize so far. Sceptics contend that:

1) Proxy evidence for previous natural warmings and coolings has been minimised or ignored.

2) Instrumental evidence for warming has been exaggerated by selectivity and poor station keeping. We can expect a paper on this from the Watt's team in the new year.

3) The co2 record is dominated by the Mauna Loa data, which is kept by Charles Keeling's son. Ignored data shows much greater variation in co2 levels over the last 150 years.

4) The natural recovery from the little ice age, 60 year oceanic cycles, and multidecadal variation in cloud cover have not been properly factored in to calculations of climate sensitivity, which has led to an exaggerated figure for the effect of co2.

5) The solar variability has had it's effect on climate variation underestimated due to it's supposed non correlation with temperature since 1980. If this is understood as largely an effect of (2), then the sun comes back into play as a more dominant climate influence. This will further diminish co2's role in (4).

So finally to your question about disproving the A in GW.

6) Sceptics are saying that the foregoing issues mean that whatever role co2 does play in global temperature, it is much smaller than the claims made by proponents of the AGW hypothesis.

Conclusion

7) We are discussing climate analysis, rather than some kind of lab operable climate science, which cannot deliver definite prognoses of real world climate, due to the number of confounding factors in the data, and a low level of scientific understanding of potentially large factors.

[Nereid]

Sure UHIs could be classed as agw

I doubt it ... it's an example of AW (anthropogenic warming), but no one is even trying to make a case that UHIs raise the average temperature of the whole Earth (i.e. GW) by more than a trivial, unmeasurable extent ... at least as far as I know.

, but they are actually ignored within the mainstream defintion of agw. The main thrust of agw theory as concluded by the IPCC is that Co2 is the main culprit. So no, even if UHIs are primarily responsible for a warming average we'll need to call it something else because the "agw" tag is a specific reference to Co2.

Of course UHIs are a local phenomenom in that they may warm the temperature around a city by about a 1 degree compared to the rural areas. Atleast last time i measured the difference in Malaga (Spain) which is not a large city (pop 500,000).

And the problem if UHIs are responsible for all the warming is what do we do about it? Or is it even a problem if confined to a local 1 degree of warming? That's not the end of the world.

I dont think there has been a study which has purposefully pulled city temperatures from the overall record and then compared the city+rural average with a rural only. That would be interesting. All the major datasets today include city temperatures which is frankly highly unscientific from what we know about UHIs.

I'm having trouble, Jetlack, and I hope you can help me.

You see, your response does not seem to answer any of the questions I actually asked! What you write might be interesting, but it's not helpful in terms of providing me insights into the scientific basis of Bright_Light's post.

Can you help me please? How can I ask my questions so that you understand them better?

[Nereid]

Again, thanks for the response, Stroller.

It has been difficult to get contrarian papers published, for reasons the leaked emails from the CRU make obvious.

I've seen claims like this, of course, and I intend to look into them ... later (FWIW, in my experience "contrarian" papers have difficulty getting published - in the main, peer-reviewed journals - because they fail to meet basic standards, as science; nevertheless, it's not all that hard to get a preprint onto arXiv, or to publish in a lesser-known journal.)

Rather than trying to 'prove a negative', (no A in GW)

Perhaps I was not clear enough in my statements and questions; let me try again.

Developing testable hypotheses is, IMHO, a key part of doing science.

Bright_Light's post seems - to me - to overlook this ("There is NO converse theory or claim thus there is NO theory to defend", for example), and I'm trying to understand if this is, in fact, so.

To do that I posed what I thought was a pretty straight-forward question ("is there a consistent position (narrative, case, ...) wrt (something like) the impact of the activities of us humans on global warming, in the last century or so, is below the level of detectability (as of today)?"), but for some reason or other (or reasons), neither you nor Jetlack seems to have grasped what I am trying to get at.

I've learned that there's - apparently - a consistent position (narrative, case, ...) that the impact of the activities of us humans on *local* warming, in the last century or so, is *well above* the level of detectability (i.e. UHIs) - testable hypotheses have been developed, tested, and the results are clear; but of course that's not an answer to my question.

sceptics have said that the uncertainties are such that the changes in temperature we have seen are within the bounds of natural variability and comparable to previous times before co2 increase.

As you - or perhaps it was someone else - have pointed out, internet blogs are full of this sort of thing.

However, my question concerns consistency, the impact of the activity of humans, global warming, the last century or so, and detectability.

Can you connect the dots please? Specifically, how does what you say about what skeptics have said tie into my question?

This is why the existence of the medieval warm period has been such a battle ground between sceptics and AGW hypothesis proponents. Good evidence from worldwide sources such as the Greenland ice cores are ignored or marginalised in the literature.

Here is a file containing the individual country records from 1900 before they are processed by CRU's HADcruT2 'code', but after homogenisation by GHCN.
http://strata-sphere.com/blog/wp-con...5_vs_2008b.pdf

As you can see, there are many countries which show little warming over the C20th according to this data. The Russian data in the very bottom graphs only represents 40% of the landmass of Russia, which itself is over 10% of the global landmass. Stations north of 70 degrees which show no warming have been ignored.

To summarize so far. Sceptics contend that:

1) Proxy evidence for previous natural warmings and coolings has been minimised or ignored.

2) Instrumental evidence for warming has been exaggerated by selectivity and poor station keeping. We can expect a paper on this from the Watt's team in the new year.

3) The co2 record is dominated by the Mauna Loa data, which is kept by Charles Keeling's son. Ignored data shows much greater variation in co2 levels over the last 150 years.

4) The natural recovery from the little ice age, 60 year oceanic cycles, and multidecadal variation in cloud cover have not been properly factored in to calculations of climate sensitivity, which has led to an exaggerated figure for the effect of co2.

5) The solar variability has had it's effect on climate variation underestimated due to it's supposed non correlation with temperature since 1980. If this is understood as largely an effect of (2), then the sun comes back into play as a more dominant climate influence. This will further diminish co2's role in (4).

So finally to your question about disproving the A in GW.

6) Sceptics are saying that the foregoing issues mean that whatever role co2 does play in global temperature, it is much smaller than the claims made by proponents of the AGW hypothesis.

Conclusion

7) We are discussing climate analysis, rather than some kind of lab operable climate science, which cannot deliver definite prognoses of real world climate, due to the number of confounding factors in the data, and a low level of scientific understanding of potentially large factors.

But, to repeat, has anyone produced, in a single document (or series of inter-connected documents) a consistent position (narrative, case, ...) wrt (something like) the impact of the activities of us humans on global warming, in the last century or so, is below the level of detectability (as of today)?

So far, at least, it would seem that the answer is "No".

[Nereid]

[...]

Sceptics contend that:

[...]

5) The solar variability has had it's effect on climate variation underestimated due to it's supposed non correlation with temperature since 1980. If this is understood as largely an effect of (2), then the sun comes back into play as a more dominant climate influence. This will further diminish co2's role in (4).

[...]

I don't think I've seen this before; can you point me to any published papers on it please?

I am - for obvious reasons - quite interested in science-based material on the intrinsic variability of stars ...

[Jetlack]

I doubt it ... it's an example of AW (anthropogenic warming), but no one is even trying to make a case that UHIs raise the average temperature of the whole Earth (i.e. GW) by more than a trivial, unmeasurable extent ... at least as far as I know.


I'm having trouble, Jetlack, and I hope you can help me.

You see, your response does not seem to answer any of the questions I actually asked! What you write might be interesting, but it's not helpful in terms of providing me insights into the scientific basis of Bright_Light's post.

Can you help me please? How can I ask my questions so that you understand them better?

I wish i could but i am in the same state of uncertainty as you. I have looked high and low for a slam dunk case either way re:agw and have found none. Hence why i am in favour of totally new analysis of the temperature record by indpendent teams (with a pre-agreed criteria for selection and homogenisation of data). If 2 or 3 teams working in isolation of eachother, using the same unbiased process all come to the same conclusion then i think the science would be on far firmer footing.

We would not accept the current level of uncertainty or unfalsifiability in any other hypothesis in the sciences so why are we should we accept less than high standards in determining the veracity of the agw hypothesis?

But no sorry, currently, i cant point you to any clear cut evidence on either side of the argument.

[Stroller]

I don't think I've seen this before; can you point me to any published papers on it please?

I am - for obvious reasons - quite interested in science-based material on the intrinsic variability of stars ...

It's a fairly contentious and complex area, because it rests on small changes in the sun's overall output in terms of TSI, and the splicing of data from several satellites over the period of record.

There are two main camps. The ACRIM team, who maintain the sun increased it's TSI output right through to 2003, and the PMOD team who use models to justify the 'adjustment' of the ACRIM data. Something strongly contested by the scientists who ran the experiment.

The published papers you should look at include those by Scafetta and West, those by Svalgaard, and those by Frolich, Lean and Rind. Also, papers by Mike Lockwood are relevant.

To understand how solar variability miht be amplified by other terrestrial and celestial phenomena, take a look at Nir Shaviv's paper on using the oceans as a calorimeter, and Henrik Svensmark's work on GCR's and clouds.

Additionally, you may be interested in the analysis I myself presented earlier in this thread on steric sea level rise and the implicated energy gain of the oceans due to insolation 1993-2003. Also my graphs of cumulative sunspot counts and my reproduction of C20th century temperature change from a combination of sunspot counts and changes in length of day. I propose the underlying cause of both these phenomena to be changes in the relative motion of the sun and the centre of mass of the solar system, which is a function predominantly of the orbits of the gas giant planets.

[Stroller]

Developing testable hypotheses is, IMHO, a key part of doing science.

But, to repeat, has anyone produced, in a single document (or series of inter-connected documents) a consistent position (narrative, case, ...) wrt (something like) the impact of the activities of us humans on global warming, in the last century or so, is below the level of detectability (as of today)?

So far, at least, it would seem that the answer is "No".

Both camps have the same difficulty here, hence my comment that in truth, we are doing climate analysis rather than climate science. This is due mainly to uncertainty in data, conflicting data from different acquisition methods, lack of transparency in methodology and details of sub-sampling choices, and the lack of reliable baselines which can exclude confounding variability from factors which we have a low level of scientific understanding about.

Properly testable hypotheses are in short supply.

[Ari Jokimaki]

You should look at this and that... but no single link to a paper or specific reference. Genuinely helpful people give links.

[Ari Jokimaki]

James Hansen on global surface temperature analysis.

[nauthiz]

I dont think there has been a study which has purposefully pulled city temperatures from the overall record and then compared the city+rural average with a rural only. That would be interesting. All the major datasets today include city temperatures which is frankly highly unscientific from what we know about UHIs.

Well there's that one I linked to you, but you seem to have rejected it on the grounds that known artificial biases were removed from the data in order to get a cleaner signal before checking to see what's going on with another artificial bias.

You don't seem to have responded to that yet. I would at least be interested to know why you suspect that some of the adjustments might have been able to shrink such a signal by a factor of 10, and which adjustments those might be.

I'm also interested to know how the USHCN and NCDC are "dependent on the Jones and Mann brigade."

[nauthiz]

Another thought: The land station temperature record is not the only temperature record. Far from it.

If we were to find that the bias due to the urban heat island effect is, in fact, introducing an uncorrected bias that is many times larger than 0.006C/decade in the land surface record, that would indeed be problematic.

But it would not be because it rubbishes the idea that the planet is warming. Instead, it would raise questions about how it can be that every other temperature record of note* shows a warming trend that corresponds to model predictions but the measurements from weather stations do not. That might result in some pretty deep changes to the model having to be made. . . but that would not in any way warrant the assumption that such changes would end up rubbishing the overall gist of the model.

(It's been 150 years this year since Le Verrier reported his discovery about Mercury. That announcement set off a chain of events that I think serves as a good counterexample.)


* I know, post-1960 tree rings don't seem to. But we don't even really know how to read tree rings quite yet. When a developing technology disagrees with everything else, my first instinct is to assume it's because the technology still needs more development. I'm inclined to stick with this until compelling evidence to the contrary indicates otherwise. Until that happens, contemporary tree ring proxy data does not qualify as a "temperature record of note".

[Stroller]

The plot thickens on the New Zealand surface temperature story.
http://briefingroom.typepad.com/the_...temp-data.html
http://www.investigatemagazine.com/hessell1980.pdf

[nauthiz]

Some googling around indicates that this paper is not long-forgotten, or at least published researchers remember it often enough for it to show up in bibliographies. Don't have too much more information since most of what I'm finding is stuck behind a paywall, though.

I also don't see much indication that Hessell's paper fell on deaf ears, something that I'm not willing to just assume. It was published 30 years ago; everywhere else in the world the methods for collecting and analyzing the weather station records has changed during that time - why not New Zealand?

Actually, the article itself implies that a re-analysis has occurred. The magazine article indicates a 1C increase over the past 100 years. The 1980 Hessell paper indicated 1C of warming over the previous 40 years.

So right now the plot that's thickening looks to be the usual "shoddy scholarship on the part of some journalists" one to me. . .

[Stroller]

This looks like a useful resource for those wanting to find out about the medieval warm period, and it's global extent.

http://www.co2science.org/data/mwp/mwpp.php

[William]

Evidence that that the surface temperature data has been cherry picked and manipulated to create a larger global warming number than reality is the discrepancy between surface temperature measurements and satellite temperature measurements of the lower stratosphere.

The assertion that the Russian temperature measurements for 40% of the Russian stations was not used in Global Surface temperature calculation as the stations in question showed minimum warming supports the assertion that a portion of the 20th century warming was created by cherry picking and manipulation of the data.

The Russian data has a larger affect on the calculation as it is used to adjust high latitude temperatures in the Canada.




http://icecap.us/images/uploads/Klotzbah_etal.jpg

http://pajamasmedia.com/blog/daleo-a...m-exclusive/2/

[William]

This is more concerning the allegation that surface temperature data has been manipulated and cherry picked.


http://pajamasmedia.com/blog/daleo-a...m-exclusive/2/

We now know that the Russian station count dropped from 476 to 121, meaning “over 40% of Russian territory was not properly included in global-temperature calculations for some other reasons, rather than the lack of meteorological stations and observations.”

In the IEA report, there is a chart showing CRU’s selective use of 25% of the Russian data created 0.64C more warming than was exhibited by using 100% of the raw data. Given the huge area Russia represents (11.5% of global land surface area), this significantly affects global land temperatures.

We know from the maps that NASA produces — produced using NOAA GHCN data — that Canada is largely missing. As is Greenland. The Arctic. Much of Africa. Brazil. And parts of Australia. (See this post.)

To fill in these large holes, data was extrapolated from great distances away. Often the data came from lower latitude, lower elevation, and higher population centers. In addition to station dropout, the number of missing months increased by as much as tenfold in many of the remaining areas. This required filling in of data from surrounding stations, again sometimes considerable distances away from the missing location. Another opportunity for error, if not mischief.

[William]

http://www.climatesci.org/publications/pdf/R-345.pdf

This paper investigates surface and satellite temperature trends over the period from 1979-2008. Surface temperature datasets from the National Climate Data Center and the Hadley Center show larger trends over the 30-year period than the lower-tropospheric data from the University of Alabama-Huntsville and Remote Sensing Systems datasets. The differences between trends observed in the surface and lower tropospheric satellite datasets are statistically significant in most comparisons, with much greater differences over land areas than over ocean areas. These findings strongly suggest that there remain important inconsistencies between surface and satellite records.

[William]

This change at Wikipedia should bring the Medieval warm period back to Wikipedia.

Unbiased scientific data and analysis is fundamental to understanding this issue.


http://wattsupwiththat.com/2009/12/1...e-information/

[Jetlack]

Well there's that one I linked to you, but you seem to have rejected it on the grounds that known artificial biases were removed from the data in order to get a cleaner signal before checking to see what's going on with another artificial bias.

You don't seem to have responded to that yet. I would at least be interested to know why you suspect that some of the adjustments might have been able to shrink such a signal by a factor of 10, and which adjustments those might be.

I'm also interested to know how the USHCN and NCDC are "dependent on the Jones and Mann brigade."

Its not necessarily they are dependent on eachother, but USHCN has their own problems with poorly positions temperature stations.

I've made it clear I'd like to see new research going foward which can be categorically classed as independent, without any political driving force (or self-interests) such as IPCC (which is a political construct). So in my opinion, anything that the IPCC has used as so-called evidence is immediately suspects seeing how many of the lead authors have behaved.

And there are other independent projects going on right now such as CERN's Cloud09 headed by Jasper Kirkby which will be deliveirng results on potential correlations between solar and cosmic influences on clouds, and other climatic conditions on earth.

I'd rather wait for much more science to be done before coming to the sort of drastic conclusions you keep referring to as gospel in the IPCC reports.

[nauthiz]

So, if I understand this right, what you're saying is you don't know of any compelling objections or evidence to suggest that the current quantification of the uncertainty introduced into the measured warming trend which is attributable to the urban heat island effect have been grossly understated. All you seem to have is politics and ad homs.

Fair enough, but you'll have to forgive me if I don't find that as compelling as you do.

[Stroller]

I'd rather wait for much more science to be done before coming to the sort of drastic conclusions you keep referring to as gospel in the IPCC reports.

At least one of the IPCC co-ordinating authors agrees with you.

19/11/2009
It isn’t necessary to list all the changes I have identified between what the scientists actually said and what the policy makers who wrote the Summary for Policy Makers said they said. The process is so flawed that the result is tantamount to fraud. As an authority, the IPCC should be consigned to the scrapheap without delay.

http://www.stoptheaclu.com/2009/12/1...ut-ipcc-fraud/

[tusenfem]

http://www.stoptheaclu.com/2009/12/1...ut-ipcc-fraud/

Stroller, I seem to remind asking for more peer reviewed science in this thread. However, what you link to is a far right, anti-science platform (from the ads on the page it seems basically against any modern science). Stop this nonsense now, if you want to keep on posting on this platform. If you have no real science to bring here, then you can refrain from posting.

This last sentence holds for all participants in this thread, some of which are indeed capable of looking up real science sources through ADS (available to anyone, but yes, you have to learn how to search) or through ISI, with only limited access (I think) if you don't have a subscription.

Now move this thread back to where is belongs and discuss the science, and if you can't find what you want, then maybe you should try for yourself to do something, or ask for help doing it.

[Stroller]

Tusenfem.
My apologies for the misunderstanding of my intention caused.

I'm not trying to promote the website or the views expressed in any other part of it, I was just providing a source for the rest of what IPCC co-ordinating author Dr Philip Lloyd had to say.

I will stick solely to the science from now on, as I'm sure everyone else will.

[Stroller]

Reference
Wilson, A.T., Hendy, C.H. and Reynolds, C.P. 1979. Short-term climate change and New Zealand temperatures during the last millennium. Nature 279: 315-317.

Description
"Temperatures derived from an 18O/16O profile through a stalagmite found in a New Zealand cave (40.67°S, 172.43°E) revealed the Medieval Warm Period to have occurred between AD 1050 and 1400 and to have been 0.75°C warmer than the Current Warm Period."

Now things have warmed up a bit since 1979, though looking at the study linked in William's post above regarding the difference between satellite and surface measurements, maybe not by as much as has been commonly believed.

So this is more evidence that the Medieval Warm Period was more globally extensive than has been claimed, and was slightly warmer than today's temperatures at this location.

[buzgz]

The data from the Mann, Bradley, Hughes 1999 paper were apparently used in

http://holocene.meteo.psu.edu/shared...es/MBH1999.pdf

construction of the later graph known as the Hockey Stick graph. Quite a bit of discussion has focused on the 20th century data as presented in this graph. I would like to discuss some 19th century data which also appears to contribute to the shape and interpretation of the HS.

In addition to Mann, Thomas J.Crowley has also explored warming over the past 1000 years, and has published some results different from Mann in potentially critical ways. Paying particular attention to the years between 1840 and 1910 in Fig. 2 of the article by Crowley and Lowery,

http://ambio.allenpress.com/archive/...47-29-1-51.pdf

shows that Crowley displays rapid warming during that interval that is absent from the Mann plot for the same period.

Crowley infers that Mann was aware of the apparent warming during this period but chose not to show it for reasons I don’t yet understand ("anomalous tree-ring growth due to CO2"). Crowley remarks on this “considerable deviation”, saying:

The deviation occurs in 5 of our records (White Mountains,
Colorado, Urals, and west and east China records), has
been observed before (10, 33) and been attributed to (10) anomalous
tree-ring growth due to the late 19th century rise in CO2.
Mann et al. (10) addressed this problem by removing the postulated
CO2 growth effect before estimating past temperatures.
However, because this response also occurs in the Chinese phenological
data set, another source of variance for high tree-ring
growth rates cannot be excluded.

Obviously, Crowley understood Mann’s reasons for omitting this warming trend, but nonetheless chose to include the trend in his presentation. I take this as Crowley's believing the warming trend real. As shown in Fig. 4, this decision clearly makes the Crowley and Mann graphs dramatically different in the late 1800s.

Had Mann included the 1840-1910 warming trend in his data, it appears to me that the shape of the HS would have been considerably different. The 20th century warming could have been seen as a continuation of 19th century warming (for lack of volcanic activity,etc.) and the case for AGW may have been substantially weakened.

I would appreciate a discussion of the "anomalous tree-ring growth" referenced in the two articles and whether Crowley was correct in leaving it in and/or Mann was correct in taking it out.

This is a major point of confusion to me, especially as it might impact the HS graph shape and interpretation. Any help would be welcomed.

[Trakar]

How about areas which show no warming over 100 years? Like the Siberian surface stations north of 70 degrees CRU decided not to include in their global temperature product.



Given the sparseness of data near the arctic circle, I can see no reason to exclude these data, except for reasons of bias.

Exactly what is your source with regards to Siberian temp data? I don't know how CRU incorporates (or doesn't) such data but it is included in NASA sponsored and other private and public analyses as well as those of the IPCC, and none of these indicate a lack of warming over the last century.

http://www.iop.org/EJ/article/1748-9..._4_045013.html

http://www.springerlink.com/content/r1441120pj872844/

http://data.giss.nasa.gov/gistemp/2005/

[William]

Exactly what is your source with regards to Siberian temp data? I don't know how CRU incorporates (or doesn't) such data but it is included in NASA sponsored and other private and public analyses as well as those of the IPCC, and none of these indicate a lack of warming over the last century.

http://www.iop.org/EJ/article/1748-9..._4_045013.html

http://www.springerlink.com/content/r1441120pj872844/

http://data.giss.nasa.gov/gistemp/2005/

Trakar,
It has been known for sometime that there is an unexplained statistically bias between the satellite temperature measurements the climate center calculated temperature data.

You picked 2005 as the global temperature anomaly in that year appeared to be a global increase in planetary temperature.

The 2008 global temperature anomaly appears to be limited to the Arctic and to Russia. The strongest warming appears to be curiously in Russia. There is no scientific explanation as to why the warming should be strongest in Russia.

Also note the global temperature anomaly in 2008 was 0.44C not 0.7C which is the number that is repeated in news papers. 2009 was warmer as that is an El Nino year, however, it seems this El Nino is different as North America, Europe, Russia, and China are all experiencing a cold winter.

Also note that Arctic Ice has increased 2007 over 2008 and 2009 over 2008 which would indicate the Arctic is cooling.

As noted the US has shown no significant temperature increase in the period.

The AWG mechanism should warm the entire planet not just specific areas such as the Arctic and Russia.

http://www.climatesci.org/publications/pdf/R-345.pdf

This paper investigates surface and satellite temperature trends over the period from 1979-2008. Surface temperature datasets from the National Climate Data Center and the Hadley Center show larger trends over the 30-year period than the lower-tropospheric data from the University of Alabama-Huntsville and Remote Sensing Systems datasets. The differences between trends observed in the surface and lower tropospheric satellite datasets are statistically significant in most comparisons, with much greater differences over land areas than over ocean areas. These findings strongly suggest that there remain important inconsistencies between surface and satellite records.

http://data.giss.nasa.gov/gistemp/2008/

http://data.giss.nasa.gov/gistemp/2008/Fig1.gif



http://www.ncdc.noaa.gov/sotc/get-fi...=gif&id=110-00
http://www.ijis.iarc.uaf.edu/en/home...extent.htm#top

http://www.ncdc.noaa.gov/sotc/get-fi...=gif&id=110-00 http://www.ijis.iarc.uaf.edu/en/home...extent.htm#top

[Stroller]

Obviously, Crowley understood Mann’s reasons for omitting this warming trend, but nonetheless chose to include the trend in his presentation. I take this as Crowley's believing the warming trend real. As shown in Fig. 4, this decision clearly makes the Crowley and Mann graphs dramatically different in the late 1800s.

Had Mann included the 1840-1910 warming trend in his data, it appears to me that the shape of the HS would have been considerably different. The 20th century warming could have been seen as a continuation of 19th century warming (for lack of volcanic activity,etc.) and the case for AGW may have been substantially weakened.

I would appreciate a discussion of the "anomalous tree-ring growth" referenced in the two articles and whether Crowley was correct in leaving it in and/or Mann was correct in taking it out.

This is a major point of confusion to me, especially as it might impact the HS graph shape and interpretation. Any help would be welcomed.

Beck's co2 analysis would seem to bear out a higher level in the mid-late C19th. This was coincident with high sea surface temperatures according to Hadley. Solar activity was also high during this period.

The bit I don't get is this; If trees enjoyed anomalous growth due to raised co2 levels in that period, how come they didn't do the same after 1960, such That Mann and Jones had to use "Mike's Nature trick to hide the decline."?

It seems likely that there are confounding variables affecting tree growth which haven't been accounted for by Crowley or MBH, or by Jones, Briffa and the CRU. We are assured that this 'divergence problem' is well known and has been extensively treated in the literature, but I haven't seen any specific links to papers on this issue put forward as the best explanation as yet.

As for whether it is better to leave it in or take it out, it seems obvious to me that the only scientifically honest thing to do is leave it in and draw attention to it as something which is a problem yet to be resolved.

Otherwise, people might get the wrong impression that tree rings are highly reliable and trustworthy temperature proxies.

[Stroller]

Exactly what is your source with regards to Siberian temp data? I don't know how CRU incorporates (or doesn't) such data but it is included in NASA sponsored and other private and public analyses as well as those of the IPCC, and none of these indicate a lack of warming over the last century.

http://www.iop.org/EJ/article/1748-9..._4_045013.html

http://www.springerlink.com/content/r1441120pj872844/

http://data.giss.nasa.gov/gistemp/2005/

The source of the graph I presented is here:
http://www.iea.ru/article/kioto_order/15.12.2009.pdf

Your first link seem to be about models based on observations handled in a paper printed in a computer tech journal, whose authors relied on the 2000 IPCC report.

[Jetlack]

So, if I understand this right, what you're saying is you don't know of any compelling objections or evidence to suggest that the current quantification of the uncertainty introduced into the measured warming trend which is attributable to the urban heat island effect have been grossly understated. All you seem to have is politics and ad homs.

Fair enough, but you'll have to forgive me if I don't find that as compelling as you do.

Thats a ridiculous reading of what i said, all carefully misrepresented by your good self. And what ad hom are you talking about?

And there are plenty of good reasons to be suspicious of the IPCC conclusions seeing how the head of it is well entangled with business interests which will gain tremendous amounts financially from worldwide Co2 regulation, taxes and research.

This is a fact. We monitor politicians who have conflicts of interests in business, so i dont see why we should suspend that standard of ethics in the case the IPCC and its officials.