I think that we would all agree that to form any kind of theory about whether or not anthropogenic climate change is occurring, we really do need to have some vaguely reliable data; after all, if there is no actual warming, then it's a little difficult to say that we're causing it.
The trouble is that gaining a temperature reading for the entire world is actually a little tricky; it's a big planet we live on, and an awful lot of the surface area is made up of water. However, that hasn't stopped the Goddard Institute of Space Studies (GISS)—headed up by our old friend James Hansen (an enthusiastic proponent of anthropogenic global warming. Except in the seventies, when he was an enthusiastic proponent of anthropogenic global cooling)—relying on the land temperature record rather, than, say, satellite measurements.
There is, of course, some logic in this, as the land temperature record goes back until the late 1800s (in the US, at least), whilst satellite readings have been taken only since 1979. The trouble is that this very longevity introduces uncertainty into the temperature record: thermometers have become more sensitive, for instance, and population centres—with their attending urban heat island effect—have encroached on measuring stations once situated in the countryside.
It is, therefore, actually very difficult to gauge the average temperature over the globe with any degree of certainty, and the signal to noise ratio makes any estimate near worthless. Especially, of course, when the people responsible for the records keep retrospectively changing them, as Anthony Watts points out.
Blink comparator of GISS USA temperature anomaly - h/t to Zapruder
The last time I checked, the earth does not retroactively change it’s near surface temperature.
True, all data sets go through some corrections, such as the recent change RSS made to improve the quality of the satellite record which consists of a number of satellite spliced together. However, in the case of the near surface temperature record, we have many long period stations than span the majority of the time period shown above, and they have already been adjusted for TOBS, SHAP, FILNET etc by NOAA prior to being distributed for use by organizations like GISS. These adjustments add mostly a positive bias.
Please note that the above graph does not represent a change in temperature projections; GISS have effectively changed what they think that actual temperatures were (and their reationship to past temperatures). Which is interesting, is it not?
It is also interesting that GISS and the other agencies almost always put a positive bias on recent temperatures, and a negative bias on past temperatures. This processing has the simple effect of making more recent temperatures seem... well... higher.
Neatly illustrating this point is Climate Skeptic, with a blink graph of actual temperatures measured at the climate stations, against the end result that is passed to GISS from the US National Oceanic and Atmospheric Administration (NOAA).
My point was not that all these adjustments were unnecessary (the time of observation adjustment is required, though I have always felt it to be exaggerated). But all of the adjustments are upwards, even those for station quality. The net effect is that there is no global warming signal in the US, at least in the raw data. The global warming signal emerges entirely from the manual adjustments. Which causes one to wonder as to the signal to noise ratio here. And increases the urgency to get more scrutiny on these adjustments.
It only goes through 2000, because I only had the adjustment numbers through 2000.
Part of the problem, you see, of scrutinising the adjustments is that these agencies seem to be extraordinarily coy about releasing the data and algorithms that they use to make said adjustments. Numerous FOI requests (mainly by bloggers) have revealed some of the processes (and exposed some as being deeply flawed) but not, alas, all of them.
What we do know, of course, is that adjustments for recent years are nearly always positive, a slightly bizarre process for anyone who has been following Anthony Watts' surfacestations.org project.
If, for instance, a measurement station has been encroached upon by a population centre in the last twenty years (as many of them have) and this encroachment coincides with increased temperature readings, one might be tempted at least to investigate whether said station is being affected by the urban heat island effect. And if this is the case, the adjustments should be negative, not positive.
As it happens, we can show that this is precisely what GISS is not doing. Here, for instance, is a measuring station situated near a water treatment works in Clarinda, Iowa.
The MMTS temperature sensor is the short pole next to the half pickup truck.
For those of you that don’t know, this station is located at the wastewater treatment plant there. I’ve written many times about the placement of stations at WWTP’s being a bad idea due to the localized heat bubble that is created due to all the effluent coming though. The effect is especially noticeable in winter. Often you’ll see steam/water vapor in the air around these sites in winter, and more than one COOP observer has told our volunteers that snow sometimes does not stick to the ground at WWTP’s.
The larger pole appears to be a gas burnoff torch for excess methane. I can’t say how often it is activated (note the automatic ignitor circuit on the pole) but I can tell you that putting an official NOAA climate thermometer within a few feet of such a device is one of the worst examples of thoughtless station placement on the part of NOAA I’ve ever seen. Here is an example of a methane burn-off device at another WWTP.
We’ll probably never know what the true temperature is in Clarinda because untangling a measurements mess like this is next to impossible. How many days was Tmin and/or Tmax affected at this location by gas burnoff and to what magnitude? We shouldn’t have to ask these questions.
Quite so. But I would imagine that GISS and NOAA have this all under control, yes? I mean, I am sure that they are aware of the placing of the station and have adjusted the temperature readings down, as would seem logical.
And, adding insult to stupidity, the GISTEMP Homogenization adjustment makes the trend go positive, especially in recent years:
So, either GISS, NOAA and the rest of this merry crew are lying (in which case, you shouldn't trust a word that they say) or they are very, very bad scientists (in which case, you cannot trust a word that they say).
Of course, I am not discounting the idea that both contentions are true.
Anyway, whatever the reasons, the only conclusion that can be drawn is that the data coming out of GISS is highly suspect and, thus, so is the contention that the Earth is actually warming at all. And using such data to back a theory that any warming is caused solely by carbon dioxide (and other greenhouses gases) emitted by the activities of human beings is to discredit the entire hypothesis.
Wake up, people: you are being lied to.
UPDATE: the Beeb seems to have woken up to the fact that—even if anthropogenic warming is happening—the results might not be all bad.