People sometimes ask why climate skeptics criticize GISTEMP so much? Well it started off as a hunch, we felt that if our arch nemesis James Hansen was running it, it must be wrong. If this was merely politics that would be all we needed to believe it was wrong. But this is science and science demands evidence, so dutifully we sought out evidence to back our conclusion.
Here I bring together all the lines of evidence we have manufactured and furthermore I show how GISTEMP would look after corrections.
GISTEMP disagrees with the satellite record
The first piece of evidence is a simple observation. Since 1979 satellites have been measuring the temperature of the lower atmosphere. GISTEMP is trying to measure the temperature of the surface. The surface and lower atmosphere are not exactly the same thing, but you'd expect the temperature trend in both to be somewhat similar.
But look at how GISTEMP shows far more warming than the UAH satellite record. The disagreement is astronomical. This is what Blog Science has been banging on about for years!
Urban Heat Island Effect
Warmists will tell you there is no such thing as the urban heat island effect, but that's a complete strawman because their very own studies say there is an urban heat island effect. In fact they even try to correct for it in GISTEMP!
As Blog Scientists we must assume they don't correct for UHI enough. Blog Science knows that GISTEMP is contaminated by UHI bias. In the following graph I correct GISTEMP for UHI by 0.01C/decade.
If this was the full magnitude of UHI contamination that Blog Science was suggesting we would be just making a big deal about nothing! Don't worry we aren't. So obviously we must be talking about a far bigger correction being needed. Lets try correcting GISTEMP by 0.05C/decade for UHI bias.
That's more like it. We can now see that the allegations against GISTEMP not correcting for UHI make a big difference!
The surface record relies on sensors. Sensors are uncannily aware of the tidiness of their surroundings. They are very partial on having nice tidy surroundings and being checked on by men in smart lab coats. If these conditions are not met they refuse to measure temperature properly and just spin around, warmer and warmer, out of control.
It has been proven by Blog Science that James Hansen hasn't personally kept all the sensor locations tidy. In fact noone seems to have bothered and tourists have left rubbish like barrels and boats lying around, items known to cause warming trends. Even worse some people have installed AC units near sensors. Blog Science knows that by installing an AC unit or a boat next to a sensor, that sensor will read ever higher temperatures each year until eventually the sensor will melt.
Warmists claim that the GISTEMP algorithm statistically detects and removes such significant biases from the record. But as Blog Scientists we assume otherwise. We also demand to know why science isn't performed like in the movies? Why aren't there teams of good looking men and woman scientists in shiny suits going around in futuristic metallic science vans tidying up the sensors? Blog Science can only conclude that microsite biases are not properly accounted for in GISTEMP and that these biases cause GISTEMP to be too warm.
Like with UHI bias the microsite bias must be somewhat large or else we would just be making a big deal about nothing! So I propose another correction of 0.05C, this time for microsite bias. The following graph shows the total correction (0.1C/decade) for UHI bias and microsite bias.
We see that correcting for UHI and microsite bias has reduced the warming a lot! So much for the IPCC's predictions of children melting within 20 years.
Now lets compare the corrected GISTEMP to UAH satellite record again. The following graph shows that the previous disagreement between GISTEMP and the satellite record has disappeared thanks to our Blog Science efforts. It has been replaced with a new disagreement though.
Now the satellites show too much warming. The conclusion is obvious. It is time for Blog Science to attack the reliability of the satellite records.