Watt about Armagh?

One of today’s posts on Watts Up With That (WUWT) is by Darko Butina and is called On the scales of warming magnitudes – part 1. It appears to be a study of the temperature measurements at Armagh Observatory from 1743 till today (1743 being important, apparently, because this is when the Celsius scale was introduced!!!!). It’s been covered in some detail over at HotWhopper, so I won’t say too much. I’ll just add a few comments of my own.

The two main conclusions of the work are (and I quote)

1. That the global warming does not exists in thermometer data since it is impossible to declare one year either warmer or colder than any other year.

2. That the Hockey Stick scenario does not exists in thermometer data and therefore it must be an artefact observed in a purely theoretical space of non-existing annual global temperatures.

The post starts, however, with the claim that this work is “unique and novel in its approach to man-made global warming” because “it treats the Earth atmosphere as a system where everything is local and nothing is global”. Hold on a second! Noone is suggesting that global warming implies that every location on the planet today should be warmer than it was in the past. Global warming is a process in which the amount of energy in the system increases with time which leads to an increase in the global average temperature, increases in the heat content (and hence temperature) of the oceans, and reductions in the amount of permanent polar ice. I don’t believe any credible scientist would regard data from a single site as being suitable for determining if global warming was occurring or not.

The post then goes on to say that we can determine if there has been an “unambiguous warming trend” by comparing the daily temperatures in 2004 with those in 1844. Wait a minute! Noone is suggesting that global warming implies that there is a monotonic increase in temperatures and that the temperature now will be warmer than it has ever been in the past. It is clear that there is a lot of variability. All that global warming is suggesting is that there has been a warming trend. If one goes to the skeptical science trend calculator, one can plot monthly average global temperatures since 1880. The variation is something like +-0.3oC so it is quite possible for a recent year to have a similar average temperature to a previous year. How do we know that comparing 2004 with 1844 isn’t simply comparing a cool recent year with a warm past year, especially since the scatter locally could well be much greater than the scatter globally. Additionally, there is some evidence to suggest that there was a cooling trend prior to 1870, so 1844 may not have been a particularly cool year anyway.

Essentially, I think this work, at best, tells us virtually nothing about global warming and, at worst, is complete nonsense. The comments on a WUWT post are typically quite extreme. They are either fist-thumpingly pro anything suggesting that global warming doesn’t exist or isn’t due to man, and completely dismissive of anything supporting the idea that global warming/climate change is man-made. The comments on this post seemed (in my opinion) quite mild compared to what I had seen before. The person posting as richardscourtney (whose comments are amongst the most extreme) actually made quite a balanced comment suggesting that the methods in this work are “less than optimal” but at least they are clearly explained and can be debated. All I can conclude from this is that most know that this is probably not a particularly relevant bit of work, but can’t really bring themselves to say that.

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