Moderated Global Warming Discussion

[Pixel42]

Looking at the referenced paper again I see where this may have been picked up in my peripheral, from Smith Reynolds 2005:

As with the SST, the simple averages are generally consistent with the reconstruction average. The twentieth-century warming is about 0.6°C.

No, I'm pretty sure you got the 0.68°C from this (rather sarcastic, I'm afraid) post of mine (figure bolded):

Global temperatures were 0.5C cooler in 1881 than they are this year, and coincidentally almost exactly the same as the 20th century average? Amazing. Citation?

Incidentally you forgot to point out that this time last year

For the year-to-date, the global combined land and ocean surface temperature of 14.5°C (58.1°F) was the warmest January-July period on record. This value is 0.68°C (1.22°F) above the 20th century average.

This clearly proves that temperatures have dropped 0.17°C in just one year,. and that a new ice age is therefore imminent.

You confused my quote from the NOAA "state of the climate" website page for July 2010 with your quote from the equivalent page for July 2011.

 

[Furcifer]

1. 20th century average means the average from 1901-2000.

Nope, not for the combined average, they first used 1880-1997, then they used 1880-2006.

2. The rise in average global temperature since 1880 is actually about 0.9C.

Nope, that's the high end, it's 0.6C +/- 0.3C see post below for clarification.

3. Even 0.5C would not be insignificant in just 130 years, let alone 0.9C.

Nope. It's consistent with the natural fluctuations. The IPCC has it rising 0.2C per decade in the next two decades, that's warming. If that happens, which it most certainly won't, Global Warming is truly a problem.

If and when they refer to such an average, I expect them to call it the average from 1880-2006. I do not expect them to call it the 20th century average, because that means the average from 1901-2000.

What you expect is irrelevant, what it is is the years from 1880-2006 in the combined average.

That's about the only thing you're getting right.

Everything is correct as stated. Otherwise someone could have easily refuted it with evidence, not general references .

There is no paper referenced in the post under discussion, only a quote from the NOAA website.

Incorrect. It's referenced on every page due to it's usage on every page.

But if you know of a paper which uses "20th century average" to mean anything other than the average from 1901-2000 by all means provide a link to it and quote where it does so. Nobody else seems able to find such a use in any of the papers you've referenced.

The link has been provided, and the paper cited. It's available on every page you cited as well.

 

[Furcifer]

But if you know of a paper which uses "20th century average" to mean anything other than the average from 1901-2000 by all means provide a link to it and quote where it does so. Nobody else seems able to find such a use in any of the papers you've referenced.

You provided the link actually, and I clearly pointed it out in the references.

The "20th Century Average" we're talking about is the merged ESSTv3 (v3b was with the satelite data, which was not used)

All of the compiled reconstructions (Mergedv3,SRO5,Qualyle et. al,HadCrutv3 were broken up into 1880-1900, 1901-1950, 1951-2000, for the ESSTv3. The averages .74, .68, .77 were merged and tuned to give the 20th Century Average of 0.7 (I don't understand the tuning, it has something to do with el Nino and sea ice)

 

[CapelDodger]

Perhaps it's because any negative "bias" is simply dropped. I happened to notice this in the Land Ocean Temperature measurements.
Summary of Recent Changes in the Land-Ocean Temperature Analyses
In the ERSST version 3 on this web page we have removed satellite data from ERSST and the merged product. The addition of satellite data caused problems for many of our users. Although, the satellite data were corrected with respect to the in situ data as described in reprint, there was a residual cold bias that remained as shown in Figure 4 there. The bias was strongest in the middle and high latitude Southern Hemisphere where in situ data are sparse. The residual bias led to a modest decrease in the global warming trend and modified global annual temperature rankings

So here it is, a negative bias in the satellite data dropped because it doesn't fit the surface measurements, which have been shown to have a positive bias.
Confirmation bias?

That doesn't say anything was dropped. In fact it says there was a modest decrease in the global warming trend as measured by satellites. "Modest" meaning "slight" in this case (as opposed to "humble" or "unassuming"). Given that this applies where in situ data are sparse the satellite data is the better option, I'm sure you'd agree, but it's hardly of any great significance.

 

[Furcifer]

An interesting paper on climate sensitivity.

On constraining estimates of climate sensitivity with
present-day observations through model weighting

The distribution of model-based estimates of equilibrium climate sensitivity has not changed substantially in more than 30 years. Efforts to narrow this distribution by weighting projections according to measures of model fidelity have so far failed, largely because climate sensitivity is independent of current measures of skill in current ensembles of models.

I believe the 1979 Charney paper estimates sensitivity to be 3C +/- 1.5C. The reality is things really haven't changed much in 30 years.

 

[Furcifer]

That doesn't say anything was dropped. In fact it says there was a modest decrease in the global warming trend as measured by satellites. "Modest" meaning "slight" in this case (as opposed to "humble" or "unassuming"). Given that this applies where in situ data are sparse the satellite data is the better option, I'm sure you'd agree, but it's hardly of any great significance.

Correct.

In the ERSST version 3 on this web page we have removed satellite data from ERSST and the merged product.

It says removed, not dropped. Dropped is a synonym for removed.

 

[Furcifer]

No, I'm pretty sure you got the 0.68°C from this (rather sarcastic, I'm afraid) post of mine (figure bolded):
You confused my quote from the NOAA "state of the climate" website page for July 2010 with your quote from the equivalent page for July 2011.

I don't think so. I usually try to keep track of the decimals, not so much because they're all that important, but it makes it easier to keep track of the studies. Then again I did say 0.5C, when the actual average, pointless derail about the span aside, is 0.6C.

 

[Reality Check]

An interesting paper on climate sensitivity.

On constraining estimates of climate sensitivity with
present-day observations through model weighting

...
I believe the 1979 Charney paper estimates sensitivity to be 3C +/- 1.5C. The reality is things really haven't changed much in 30 years.

There is no '1979 Charney paper'.
Climate sensitivity

The standard modern estimate of climate sensitivity — 3°C, plus or minus 1.5°C — originates with a committee on anthropogenic global warming convened in 1979 by the National Academy of Sciences and chaired by Jule Charney. Only two sets of models were available; one, due to Syukuro Manabe, exhibited a climate sensitivity of 2°C, the other, due to James E. Hansen, exhibited a climate sensitivity of 4°C. "According to Manabe, Charney chose 0.5°C as a not-unreasonable margin of error, subtracted it from Manabe’s number, and added it to Hansen’s. Thus was born the 1.5°C-to-4.5°C range of likely climate sensitivity that has appeared in every greenhouse assessment since..."[13]

What is your point other than climate models give consistent results?
This is not a big surprise. Create models using the known physics and they tend to be consistent.

The reality is that that have been many papers calculating climate sensitivity in the last 30 years using other techniques and confirming that range: A detailed look at climate sensitivity

 

[Reality Check]

Obviously you didn't read the cited paper like you claimed.

Obviously you are just parroting what you stated before and so all I can do is assure you again that I read that paper.

I don't read junk science websites. Journals only please.

Skeptical Science does not indulge in junk science. It backs up all of its scientific articles with citations to the scientific literature.

Read Are surface temperature records reliable? which cites the journal papers and concludes from those papers that

The well-known and widely-cited reconstructions of global temperature, produced by NASA GISS, UEA CRU, and NOAA NCDC, are replicable.
Independent studies using different software, different methods, and different data sets yield very similar results.
The increase in temperatures since 1975 is a consistent feature of all reconstructions. This increase cannot be explained as an artifact of the adjustment process, the decrease in station numbers, or other non-climatological factors.

They don't need to state it, it follows logically. That's a certainty.

Still wrong.

• There is no hand waving. These papers state no implication of these biases on global temperatures. That is a fact.
• global temperatures are not based on absolute temperatures. That is why biases do not matter. That follows logically, is a fact and is a certainty.

Every single link is from a junk science website. I only read the journals for information.

Skeptical Science does not indulge in junk science.
Obviously you have never read any articles in journals on how global temperatures are calculated or that you would know that anomalies are used, not absolute temperatures. This is to remove any biases in the actual temperatures read at the surface station.



The first 2 links are primers on climate science. They say what is in the textbooks.

• Of Averages and Anomalies - Part 1A. A Primer on how to measure surface temperature change
• Of Averages and Anomalies - Part 1B. How the Surface Temperature records are built
• Of Averages & Anomalies - Part 2A. Why Surface Temperature records are more robust than we think
• Of Averages & Anomalies - Part 2B. More on why Surface Temperature records are more robust than we think

I suggest that you read at least the first primer so that you can understand how biases are eliminated.

 

[Halsu]

I have no idea what you're talking about.

I'm talking about the fact that "20th century" in scientific papers always means 1901-2000. Without exceptions.

Perhaps I was unclear, try the REFERENCES.
Please, just read the paper.

Yes, you are very unclear. Perhaps that is because you know that none of those referenced papers claims 20th century average to be anything else than the 1901-2000 average.

Yes, i checked them all.

So, could you PLEASE provide a clear link, and page number for the source of your odd claim that "20th century" means something else than 1901-2000??

 

[Halsu]

There's no definition for "20th Century Average". It varies as it is applied by the user. It specifically depends, at least in this case on the data set.

Wrong. 20th century average is the 1901-2000 average. Without exceptions.

What's the definition for the "21st Century Average"? It's not 2000-2100 is it? It's not a specifically defined quantity, it depends on the years. The 19th Century average, which is also used in the paper isn't 1800-1899, it's 1854-1899, and it's 1880-1899. Oh and it's 1880-1909.

21th century average is 2001 - present, or from 2001 to the end of data.

19th century average is 1801-1899, or from the beginning of data to 1899.

And no, 19th century average is never i.e. 1880-1909 like you claim.

As I may have mentioned, the first time the 20th Century average was calculated it was 1880-1997, the second time it was 1880-2006.

Show us the money ;-)

BTW, the newer paper, one which had the broken link, can be found here:
http://journals.ametsoc.org/doi/full/10.1175/2007JCLI2100.1

 

[Halsu]

All of the compiled reconstructions (Mergedv3,SRO5,Qualyle et. al,HadCrutv3 were broken up into 1880-1900, 1901-1950, 1951-2000, for the ESSTv3. The averages .74, .68, .77 were merged and tuned to give the 20th Century Average of 0.7 (I don't understand the tuning, it has something to do with el Nino and sea ice)

I guess you got those numbers from this paragraph:

"For the full 1880–2006 period, correlations are highest between 45°S and 70°N, with an average value of 0.74. In addition, correlations are computed using data from 1900 to 1949 and from 1950 to 1999 (not shown). For 1900–49 the average correlation for this region is 0.68, while for 1950–99 it is 0.77. "

If so, you might be interested to know that .74, .68, .77 are not averages, but rather correlations between merged.v3 and HadCRUT3v. No wonder you don't understand the "tuning" ;-)

 

[Halsu]

Nope, that's the high end, it's 0.6C +/- 0.3C see post below for clarification.

That 0.6 degrees is the value for temperature rise in 20th century, 1901-2000 (Hadcrut3 actually shows a bit more, about 0.65 degrees in the trend line):

http://www.woodfortrees.org/graph/hadcrut3vgl/from:1901/to:2000/trend/offset:0.467623

The temperature rise from 1880 to present is about 0.8 degrees in Hadcrut3 trend:

http://www.woodfortrees.org/graph/hadcrut3vgl/from:1880/trend/offset:0.521546

Edited by Gaspode: 

Changed hotlinks to links as per rule 5.

 

[Halsu]

Every single link is from a junk science website. I only read the journals for information. If you can find the links to published papers please post them, I'll gladly read them. I don't let fear mongers filter my information for me.

The problem is, you simply do not seem to comprehend the scientific papers.

The links provided give a very good explanation on measuring global temperatures in layman's terms and i'm sure reading them would benefit your understanding greatly.

As far as the site being a "junk" science site, well, it's not. As far as i can tell from comparing the texts there to the published scientific papers linked as sources, it popularizes the findings from mainstream science rather accurately and without bias.

 

[Trakar]

Looking at the referenced paper again I see where this may have been picked up in my peripheral, from Smith Reynolds 2005:

As with the SST, the simple averages are generally consistent with the reconstruction average. The twentieth-century warming is about 0.6°C.Because of the uncertainty estimates, the warming can only be confidently established between 0.3° and 0.9°C. Compared to the global average of Folland et al. (2001, 2001b), our average is similar over most of the analysis
period.

The more recent paper isn't redirecting from the NOAA website like it was previously. I don't know why?

If you are going by the Smith-Renolds 2005 paper, then you acknowledge the fallacy of your "20th century average" includes 19th century data, as they are quite clear in their distinguishment of 19th century data vs 20th century data.

"...For the nineteenth century, when sampling is most sparse and the error estimates are largest, the differences between the averaged reconstruction and the simple averages are largest...

...The uncertainty estimates indicate that the nineteenth-century anomalies should be used with caution. Part of the nineteenth-century uncertainty is due to bias uncertainty, which could be reduced using future bias corrections that incorporate a better understanding of the historical bias. However, much of the nineteenthcentury uncertainty is due to the effect of sparse sampling on the low-frequency error estimate. In any case, the twentieth-century warming is significant...

...Variations in the LST simple averages in the nineteenth and early twentieth century indicate that these large uncertainty estimates are justified...

...However, there is more uncertainty in the LST average, especially before 1940 when much of the land areas are undersampled. Since we analyzed LST and SST anomalies separately, the similarity between the two is derived from the data, and is not an artifact of the analysis method. Variations in the LST simple averages in the nineteenth and early twentieth century indicate that these large uncertainty estimates are justified. The Jones–CRU LST anomalies
are cooler than the reconstruction early in the record, when sampling is sparse and our reconstruction is more damped. After 1930, those simple averages are more consistent with the reconstruction..."

Many more instances littered throughout that paper,...additionally, while the smith-reynolds analysis is good for what it covers, it leaves out two of the areas that have experienced the most dramatic temperature increases of the 20th century, the latitudes above 60 degrees. The most recent assessment I'm aware of seem to indicate a temp rise of around 0.74^oC (MoE of +/- 0.2) for 20th century (1901-2000) and I believe this comes from the 2008 update of Smith's work (IINM - this still doesn't include high lattitude integration, which would reasonably bump this figure up a few notches).

 

[Trakar]

...I'm finished explaining this. If you feel the 20th Century Average is only the years from 1901-2000 prove it. It's stated at the NOAA as 15.8^oC, show me where it uses those years, and only those years to calculate the average. I've shown you the papers, I've explained them, that's all I can do.

Actually the burden of support and proof of assertions lies with you are you made the initial assertion and have thus far, and understandably, been unable to compellingly support.

...however, just this once, because I'm rather busy and become more distracted by demands of greater importance, this link is compellingly supportive of NOAA's base period (1901-2000) for these types of calculations and assessments:

http://www.ncdc.noaa.gov/cmb-faq/anomalies.php#mean

 

[Trakar]

...And a good thing they are, there's much too much pseudoscience and handwaving coming from warmists on the internet already.

Care to cite some examples of that which you speak?

The only one regularly demonstrated to make wild assertions and then fail to support with valid reference (AKA "handwaving" and "pseudoscience") in this thread, isn't even close to being anything I'd label as a "warmist."

 

[Halsu]

Wrong. 20th century average is the 1901-2000 average. Without exceptions.

Oh, i need to take this back a little - 20th degree average can also refer to i.e. the average from the start of data to 2000, i.e. in the case of satellite measurements and other time series where there's no coverage for the whole 20th century. However, it never refers to years before 1900, or after 2000.

 

[Furcifer]

Actually the burden of support and proof of assertions lies with you are you made the initial assertion and have thus far, and understandably, been unable to compellingly support.

...however, just this once, because I'm rather busy and become more distracted by demands of greater importance, this link is compellingly supportive of NOAA's base period (1901-2000) for these types of calculations and assessments:

http://www.ncdc.noaa.gov/cmb-faq/anomalies.php#mean

That's just a random girdded data set, it's not the land sea 20th Century average. If you read this:
The anomalies are calculated with respect to the 1971-2000 base period. Gridded data is available for every month from January 1880 to the most recent month available. You can use it to examine anomalies in different regions of the earth on a month-by-month basis. The index values are an average of the gridded values (see question #7); however, the anomalies are provided with respect to the 20th century (1901-2000) average.it reiterates what I said about the gridded data and the anomalies. It has nothing to do with what we're talking about though. I strongly suggest you read the Smith Reynolds paper instead of posting links to random web pages.
The climate doesn't follow the calendar and truncated data sets aren't always accurate because they cut things like ENSO into pieces and skew the data. There are a few other reasons explained in the paper as well.

 

[Furcifer]

If you are going by the Smith-Renolds 2005 paper, then you acknowledge the fallacy of your "20th century average" includes 19th century data, as they are quite clear in their distinguishment of 19th century data vs 20th century data.

Yes they are, but NOAA isn't on webpage linked, the average is clearly from the ESST v3, which uses the 1880-2006 data set. That's why it's important to read the reference paper instead of the webpage.