How do NOAA confidently compare global warming records that go back to 1880?

Question

Surely the technology to measure global warming is very different today than it was in 1880 if global warming was ever measured in 1880... How can NOAA confidently compare tree ring data to satellite data, etc as they are different measurements, variabilities, etc

"The monthly analysis from NOAA's National Climatic Data Center, which is based on records going back to 1880, is part of the suite of climate services NOAA provides government, business and community leaders, so they can make informed decisions."

Link Below
http://www.sciencedaily.com/releases/2010/09/100919104002.htm

Answer 1

I wish they were only using 1880 data, You are coorect about the tree rings, but that is what they use to make their useless models and the data goes much further back. For the temp data, anyone can note that there has already been an increase in temp that was as fast as what we are currently seeing in the first part of the 19th century. They can also note that all of the warming was probably not caused by man, based upon the amount of CO2 in the atmosphere. If they actually were able to read the data, they would not be making such shrill conclusions, like we increasing faster than ever before. That is pure stupidity. We are not even increasing much faster than we have seen since 1880, the idea that the earth is heating faster than ever before is just some stupid scare-mongering crap that the warmers get off on saying.



They might also note, from looking at the temp data, that man is likely only responsible for 0.4 degrees of warming at the maximum. How does this line up with their 7 degree increase in the next 100 year predictions?

Answer 2

All of the data collected comes down to temperature calculations, the measurement of temperature has not changed during that time period, so why would calculating differences in it be difficult?



There have been recorded temperature readings going back to 1880 that they're using for comparison.... what do "tree rings" have to do with it? They may be used going back for long periods, but there have actually people recording the temperature since 1880, and that is the data used for comparison.



I don't see a real question here really..... how do you compare the temperature in your freezer today to the temperature in your freezer 5 years ago -- if you've been tracking that temperature all that time, you simply pull up the numbers and do the calculation.



Unless the standard of measuring temperature has changed (it hasn't) it's not a big deal.



From the NOAA website:



"Although NOAA was formed in 1970, the agencies that came together at that time are among the oldest in the Federal Government. The agencies included the United States Coast and Geodetic Survey formed in 1807, the Weather Bureau formed in 1870, and the Bureau of Commercial Fisheries formed in 1871. Individually these organizations were America's first physical science agency, America's first agency dedicated specifically to the atmospheric sciences, and America's first conservation agency. Much of America's scientific heritage resides in these agencies. They brought their cultures of scientific accuracy and precision, stewardship of resources, and protection of life and property to the newly formed agency. "



So why, if the agencies that eventually became NOAA were formed well before 1880, would you think they would need to resort to "tree rings" as a measure of temperature going back that far? They can compare back that far, because they actually have records going back that far.

Answer 3

They are using temperature observations with actual thermometers, not temperature proxies like tree rings. That is why they say "records", not "data", they were recorded at the time. They used thermometers in the 1880's, same as now. The satellite and remote sensing data are calibrated to the same references as thermometers. This info is available at the NCDC site.

Tree ring data goes back another couple of hundred years and there are other proxies.

Answer 4

Clearly, as always you have no interest in real answers but temperatures back to 1880 are based on thermometers (as vitualguy states) tree rings are used as a proxy for temps going back beyond that.

As for comparisons you don't directly compare modern satellite data to old tree ring data, you compare satellite data or thermometer data to tree rings covering the same period which gives you an accurate guide to use on older proxy tree rings to get seasonal average temperatures, I would have thought that would be fairly obvious. (but then I forget who I'm talking to)

Answer 5

The tree-ring data are calibrated against recorded temperatures and a regression transfer function is used to scale the proxy series into degrees of temperature.



Non-homogeneity over space and non-stationarity over time in historic climate data can be, and are, known issues. They can result from changing technology in measuring systems, moving the locations of meteorological stations, and missing values or incorrect values. A repertoire of statistical quality control procedures are used to evaluate the time series properties of each dataset.



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So, Mike –



It is at least refreshing that you do not try to hide you contempt for science. You must not be very popular over in the Medicine Forum what with all your ragging on the same “fairy dust” used in biomedical research and human genetic analysis. Or are you one of those hypocrites that deny the science but take advantage of the benefits of modern medicine, science, and engineering?



>>And all of this is done without the assistance of actual statisticians.<<



If the math was fundamentally flawed, this all would have been over a long time ago because it would be unequivocal.



Arguing over varimax normalized and unrotated factors in a Principal Components Analysis of a robust dataset may not be entirely trivial and irrelevant, but it’s not far from it.



Or maybe you would like to explain to us why it is so critical and how the reality of AGW depends necessarily on whether the same explained variance – of the same solution – in the same geometric space – is maximized or not.

Answer 6

The differing amount of records from then vs now means they can't. The only good way to take the temperature of the whole planet is with sattelites, we've had those for 30 years... not enough for a reasonable person to be confident of anything back as far as 1880 for global temperatures.



I suspect we have a reasonable chance of having a good record for the temperature of central park that far back, but not much else. (there weren't any airports then either.)

Answer 7

Gary F: "A repertoire of statistical quality control procedures are used to evaluate the time series properties of each dataset."



LOL.



As Gary F says, they take a variety of different data sets, discard and/or and "adjust" non-conforming data (which is obviously "bad data") and sprinkle on some statistical fairy dust and voila, the official 1850-2010 global temperature record.



And all of this is done without the assistance of actual statisticians.

Answer 8

They can't... But that doesn't prevent them from claiming that they can.



Here is a discussion from Le Mouël et al., 2008 on the believability of so-called consensus' confidence claims...



Two main groups are involved in assembling a global data base of mean temperatures, one in the UK and one in the USA.A new data set from 1850 to the present day has been assembled by the Hadley Research Centre and is described in Brohan et al. [4]. The paper focuses usefully on uncertainty estimates and provides curves for mean temperature change from 1850 to 2005. Uncertainties in recent decades are claimed to be in the order of +/-0.15°C for the global land average, +/-0.10°C for the marine average. Corresponding values in the second half of the 19th century are +/-0.40°C and less than 0.15°C. Because the surface covered by the oceans is two-thirds of the globe, the marine data dominate the final global average, which has an uncertainty of less than 0.10°C in recent decades and less than 0.15°C in the last half of the 19th century. This is the curve used in IPCC WG1 ([10], Figure SPM-3).



[...]



We find it quite remarkable that the claimed uncertainties can be so small back to 1850. The marine

data are the focus of a specific paper by Rayner et al. [16]. Both Rayner et al. [16] and Brohan et al. [4] discuss in detail the changes in the measurement techniques over these 150 years. Prior to 1900, the total number of observations was less than 5% of the number of data after 2000 and less than 15% of the number of data after 1950. Moreover, the number of 5° square boxes with any data

(yielding monthly averages) prior to 1900 was less than 50% of the number of data after 1950. Before 1900, two thirds of the total oceanic surface had no data. It is quite remarkable that this enormous under-sampling hardly affects the uncertainties of the global temperature curves. P. Jones (pers. comm., 2007) informed us that attempting to reconstruct the global temperature means using post-1950 data, under-sampled in the way the pre-1900 data were distributed, hardly changed the global means. This would imply that the marine mean air surface temperature is a remarkably uniform field on the global scale.



We have not been able so far to obtain the files of data used by Brohan et al. [4], i.e. the actual monthly data in each 5° box prior to any processing, including computation of the ‘temperature anomaly’. P. Jones (pers. comm., 2007) writes, quite understandably, that ‘‘the aim with the global temperature grids and time series is to make the data easy for scientists to use’’, but that ‘‘the monthly station data are not available.



Le Mouël et al.found it unlikely that the claimed confidence level for the marine data prior to 1900 could be almost as good as the post-1950 data.