Editor’s Selection Icon
A while ago I wrote a post about an analysis of the US climate monitoring network led by Anthony Watts, who has a very popular climate skeptic blog.
The reason for that post was that Menne et al. 2010 had used some of Watts’ analysis to find that US surface temperature trends aren’t affected much by the station siting (and not in the way that Watts had thought – bad siting seemed to add a cold bias to the record).
Now, Watts has had his paper accepted for publication (although he’s not 1st author) and in a pretty decent journal (JGR). It’s nice to see people contributing to the field in a constructive way so congratulations are in order!
So what does the paper say?
It’s all relatively bland stuff. Here’s a quote from the abstract:
Temperature trend estimates vary according to site classification, with poor siting leading to an overestimate of minimum temperature trends and an underestimate of maximum temperature trends, resulting in particular in a substantial difference in estimates of the diurnal temperature range trends. The opposite-signed differences of maximum and minimum temperature trends are similar in magnitude, so that the overall mean temperature trends are nearly identical across site classifications.
Hmm. I can’t imagine many people getting fired up over that.
This seems quite different to the kind of thing Watts has been saying in the past about the surfacestations.org results. Deltoid has some examples.
Anyway, a couple of things strike me as interesting.
On May 8 Watts asked his readers to chip in to cover the publication costs of the paper ($2247), which he collected quite quickly. At the time I looked for the paper or abstract online but couldn’t find it. (I didn’t look too hard, only on WUWT, surfacestations.org and the JGR website and a did few searches – maybe it was out there but I thought it should’ve been linked to from a post like that.) Given how Watts had sold the surfacestations.org findings up to that point, if I’d have contributed to the costs I’d now be feeling a bit confused at how it turned out.
Also, maybe this is the end to questions as to whether surface temperature increases actually exist. With Fall et al. not really turning much up and the BEST project looking like it’ll confirm the previous surface temperature analyses, there can’t much mileage left in that argument, which was pretty much answered years ago. In that light I suppose it’ll be interesting to see what happens to surfacestations.org in the future and if Watts’ perspective changes. (It would also be really interesting to see how the Fall et al. paper changed as it went through review but I don’ suppose that’ll ever happen.)
Finally, I thought it would be worth noting that I do think it’s important to keep looking at the temperature record, how it stands up and how it can be improved. Watts has helped with that in some respect. But overstating conclusions is not helpful.
Souleymane Fall, Anthony Watts, John Nielsen-Gammon, Evan Jones, Dev Niyogi, John R. Christy, & Roger A. Pielke Sr. (2011). Analysis of the impacts of station exposure on the U.S. Historical Climatology Network temperatures and temperature trends Journal of Geophysical Research
Andy Russell's weather and climate blog 
May 16, 2011 at 2:40 pm |
The paragraph you quoted from ends with this sentence:
“According to the best-sited stations, the diurnal temperature range in the lower 48 states has no century-scale trend.”
That was a surprise given the tenor of this post: “… maybe this is the end to questions as to whether surface temperature increases actually exist.”
Did you mean that we can now say the answer to that is that surface temperature increases do not exist? Or that, pace Keenan in the WSJ, the data do not contain statistically significant trends?
May 16, 2011 at 2:58 pm |
I don’t think diurnal temperature range is very important. Do you?
What’s more, the “century-scale” bit covers some interesting detail. Before Fall et al., it seems that the only work on diurnal temperature range showed a negative trend from the mid-century to 1980s-ish. What Fall et al. found was that this has increased again since the 1980s. So there’s no “century-scale trend”.
But that tells you very little about mean surface temperature trends.
May 17, 2011 at 10:45 pm
I have heard it claimed that the reduction in diurnal temperature range over the past few decades provides evidence that GHG increases are responsible for the warming. In that sense, some people think diurnal temperature range is important.
Incidentally, I don’t think Fall et al. were the first to find that DTR has increased since the 1980s. I read a paper that said much the same thing a few years ago.
Sorry for the lack of references to back up these statements. I’m a little too busy at the moment to chase them up.
May 18, 2011 at 8:43 am
Ok, so I’m probably not giving DTR as much significance as it deserves.
My point is that I don’t really care about DTR. I don’t think I know anyone who has a particular interest in DTR. If this paper had been published by anyone else I wouldn’t have looked at it. It’s not very interesting. It’s just another paper on climate observations that fits in with the “consensus view of climate change” or however you want to put it. That’s useful, but not to me or most people.
If, however, the paper had shown what Watts has been saying it would show for quite a while now (i.e. that the postitive temperature trend in the surface station record in the US was an artefact of poor station siting) then that would have been very interesting. To me and to many other people.
But it didn’t.
May 16, 2011 at 4:49 pm |
So Peter… If the diurnal high and the diurnal low both rise by 1°C, you think this means there has been no warming? After-all, the diurnal range hasn’t changed! Others might draw a different conclusion.
May 17, 2011 at 8:26 am |
I understand diurnal range has significance, and the relationship between day and night time temperature ranges is important, especially with regard to the period 1950 to 1980 when the effect of man-made global warming, it has been argued, was masked by a cooling but revealed by the changes in the relationship between these ranges.
I further understand that this argument is based on the idea that human pollution caused this daytime cooling, that it affected the range of day time temperatures as well as the difference between night time temperatures which continued to show warming, and daytime ones that didn’t. This makes day time temperature range significant: if this is right it would be expected to show a variation that correlates with human activity.
But this isn’t my field; I’m just reading what I can in an attempt to understand as much as possible about an important issue and, for me at least, that means reading Watts and reading this blog. Just searching out stuff you’re already disposed to accept isn’t good enough. My comment was prompted by what struck me as a somewhat partial quotation and exasperation: I’m with Feynman when he said you should point out the problems with a theory, not just the things that support it.
[It’s not really a “partial quotation” is it? That sentence you are interested in is stuck on the end of the abstract as a new paragraph and isn’t really related to the 2 sentences I quote and which are related to the subject of this post. I’m not really interested in DTR and I doubt Watts was either. – AR]
At least Watts invites people with different views to post on his blog and has been at the forefront of attempts to cross the ideological divide, not least with Judith Curry.
Ben, of course you’re right. Andy, a century is an arbitrary scale, of course.
I’d still be interested in your take on statistical significance.
May 17, 2011 at 12:05 pm |
In what way has Watts atempted to cross “the ideological divide” ?
May 17, 2011 at 3:16 pm |
Peter, I encourage a critical (i.e. thoughtful) reading of Anthony’s blog but my god do you really think he’s “at the forefront of attempts to cross the ideological divide”? Anthony has done more to harden denialist thought than anyone, with the possible exception Marc Morano.
The “different views” he solicits are unthreatening fig-leaves.
May 17, 2011 at 3:24 pm |
I’ve got no problem with most of what Keenan says, although he’s not the first/only person to be saying these things. There’s a JoC paper from 2010 and it was one of the useful points to come out of the UEA email enquiries (i.e. working more with stats people). Not sure where the funding was supposed to come from for these new people though!
I suppose the bigger problem comes down to climate science covering so much stuff – you can’t just look at problems from a stats/dynamics/modelling/chemistry/radiation/whatever perspective for too long before a) not getting very far or b) needing to doing something you’ve not done before.
May 19, 2011 at 7:21 am |
Am surprised nobody claimed it was irrelevant as the US only covers 2% of the globe…
May 19, 2011 at 7:43 am |
Maybe that’ll be Watts’ next move: if you can’t find anything in the US, let’s give Europe a go.
I can’t imagine there’d be much enthusiasm left for such a project, though.
May 19, 2011 at 9:26 pm |
my take is that these tempreature records might not matter on a global level, their local relevance is severely compromised. If we are to take action, it has to be on a local level, so we need good insight. Will it be cooler in london or warmer in london? Will the sea-level rise in the Nort Sea such that the Dutch need to raise the Ijsselmeer dyke and the Schelde defences? Thje anlysis shows that the local – ie useful – data is severely compromised. Doesn’t it?
May 23, 2011 at 12:42 pm |
[…] was pleased to read a good summary on Andy Russell’s Our Clouded Hills blog of the paper co-authored by renowned climate sceptic […]
October 21, 2011 at 8:27 am |
[…] pretty much confirms the recent work of Menne et al. (2010) and the Watts paper and will hopefully put this issue to bed. Indeed, the thrid paper, which specifically mentions […]