REPLY: Go for it. I’m jammed up today, fires are threatening again. 1/4 mile visibility due to smoke.
Added reference: A number of comments ask why the historical numbers change. I wrote a post on that earlier this year, which was publicized on this blog and Climate Audit. I am not saying it is OK that they change, only describing why they change.
Paul Clark:
Excellent questions and the crux of the debate. Sorry to say that the answers are highly subjective and time sensitive. There are so many variables to take into account that a definitive answer to “are we warming” is impossible or incomplete at best. With the difference in measuring devices, locales, times of observations, changes in any of the these, and throw in the accuracy of the observer, to make any judgment is premature. As Anthony has pointed out with his auditing of stations and Steve McIntyre’s overall Climate Auditing, it becomes clear that the strict discipline needed in Science is regretfully absent in the field of Climate Science and makes answers highly suspect and open to question.
The reason GISS is so cool this month is the Antarctic. I’ll throw up the link to the GISS map for June 2008 again, just in case you missed it. Scroll down to the zonal mean plot. They have to lIve with the 1200km smoothing either way it leads them.
http://data.giss.nasa.gov/cgi-bin/gistemp/do_nmap.py?year_last=2008&month_last=6&sat=4&sst=1&type=anoms&mean_gen=06&year1=2008&year2=2008&base1=1951&base2=1980&radius=1200&pol=reg
[This namespace collision is confusing even me! In case anyone hasn’t realised, there are two Paul Clarks posting here – Paul H. Clark is the other one (Hi, namesake!). I’ve changed my display name to include ‘woodfortrees’ to try and make it more obvious who’s who.]
To answer Paul H.’s question indirectly: Here is the HACRUT3 data for NH, SH and global, moderately smoothed:
http://www.woodfortrees.org/plot/hadcrut3vgl/mean:60/plot/hadcrut3vnh/mean:60/plot/hadcrut3vsh/mean:60
So yes, it has warmed a bit, and may still be warming a bit, but there’s no evidence in these records yet of anything that looks like runaway positive feedback.
On the question of data manipulation, I personally think the different datasets tally pretty well, and since they’re all derived differently any adjustments are not having a great effect on long-term changes, which is all that really matters. So as an engineer if I ask myself “can I rely on this data?”, my answer would be “Yes, to a first approximation over long term trends”.
More notes on comparing different datasets, and in particular the baseline issue: http://www.woodfortrees.org/notes#baselines
Cheers
Paul (R) Clark
With respect to datasets I have been playing with the UAH dataset and comparing the northern and southern hemisphere figures. I graphed them in Excel then created a third order polynomial trend line. The odd thing which came out is that the southern hemisphere has a lower variability than the north. Would this be because of the greater sea area in the south or just a statistical oddity.
http://www.holtlane.plus.com/images/uah_anomaly.jpg
Hadley is now out, BTW. It does occasionally do this on a Saturday! Also unusually Hadley is Higher that GISS for this month, coming in at +0.314C. Not sure if I’m reading it right, but there appears an awful lot of data missing from the SH, and Hadley doesn’t usually post quite this early in the month. http://hadobs.metoffice.com/hadcrut3/
by John Goetz
The GISS Ts+dSST numbers are in.
June comes in at 26, continuing the downward trend at GISS and making it the seventh lowest anomaly this decade.
Lots of history was rewritten by the June temperature, with 89 monthly adjustments upward and 22 downward. Most of the downward adjustments were made this decade, and most of the upward adjustments were made pre-1941. At an annual level, 9 years before 1928 were adjusted upward, and 2007 was adjusted downward.
As for 2008, Jan and Feb were unchanged, Mar up 2, Apr up 1, and May up 3. The uplifts in M-A-M surprised me some, because I would have expected out of season months (such as June) to have no effect. Such is the GISS method.
I will post up a plot later today, unless Anthony beats me to it (I like his format).