Reliable measurements or pliable estimates?

The last three posts were mostly about the adjustments of the ocean data done in the Karl 2015 paper. This because the adjustments in ocean data had the biggest impact on the result (that there wasn’t something like a “hiatus”). Kevin Marshall of the excellent blog manicbeancounter.wordpress.com reminded in a comment on previous post that surface datasets had issues as well.

I could agree with that one, I also had written a post in the first year of blogging: Things I took for granted: Global Mean Temperature,, that described how my perception of a global mean temperature changed from believer until skeptic and why I had a hard time to believe that the (surface) datasets were accurate enough to capture an 0.8 °C increase in temperature over 160 years.

Reading it back I was a bit surprised that I wrote this already in my first year of blogging. But, in line with the Karl et al paper, there were two things that I think were missing in this early piece.

First, that the data in the surface datasets are not measurements, but estimates derived from the temperature station measurements. In a way that could be concluded from the uneven spatial coverage, the convenience sampling and other measurement biases like Urban Heat Island, Time of Observation and who knows what more. This makes that the homogenized end result will just be an estimate of the actual mean temperature.

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The first turning point

My story from believer to skeptic – part 2
You might see Part 1 first if you haven’t already.

Basically, both sides seemed to have proof of their case. It was definitely a confusing time, but I carried on. At that time I mostly accepted answers from the alarmist side, giving hardly any weight to the skeptic side because I questioned their motives.

I didn’t realize it at the time, but I learned some important lessons. Firstly, it is very difficult to change a belief, especially when it was build up and maintained for so long. Secondly, if one is focused on a negative quality of someone (real or imagined), it is not possible to consider their arguments. But this was going to change soon.

To find out more about the different viewpoints in global warming, I followed many discussions online. While following such a discussion, I was directed to a site called surfacestations of Anthony Watts. On this site, USHCN weather stations were documented. Volunteers surveyed the weather stations to check if the station quality was in accordance with the specifications and some photos were taken. This information was posted on their site.

The more I navigated this site, the more I got baffled. I saw weather stations located next to air conditioner units, close to buildings and parking lots, even one on the roof of a building. These things undoubtedly will have an influence on the temperature reading. If this is the way temperatures (that prove the world is warming at an unprecedented rate) are measured, then how reliable are these records?!?!?!

The audit process was not completely finished at that time, but the end result was devastating: from memory, about 80-85% of the sites were not even compliant with the regulations, only about 15-20% would have correct temperature registrations.

My thought at that time was: if this is really true, I have a hard time believing this claim of unprecedented warming anymore. If this is how the raw data is collected, that unprecedented warming could well be an artifact of the way temperatures were measured. When the collected raw data is unreliable, then the result of the calculation with that raw data will be unreliable as well.

This made me looking with different eyes at skeptical sites. More and more I began to explore their arguments. At least in this one they seemed to have a valid point. The more I looked at the data behind global warming, the more my belief in catastrophic anthropogenic global warming started to crumble. At one point I really doubted the catastrophic/anthropogenic part, but the alarmist side still had a convincing argument in their sleeve.

Go to Part III