Search This Blog


Wednesday, August 13, 2014

The following is a comment made at SkS on the topic of how much new agricultural land will be made available in northern latitudes by global warming. It relies heavily on just one, twenty year old reference in an area in which I lack significant knowledge. It is posted primarily to provide a reference to two key sources of relevant data. I think my discussion is reasonable, but it should only used to provoke thinking on the topic rather than to take home conclusions. 

Wednesday, August 6, 2014

Thoughts on McIntyre and McKitrick 05

The following is a comment published at And Then There's Physics.  I am posting it here as a ready access source for me for the relevant links and commentary on M&M05:

Friday, February 7, 2014

Winter in the United States

Roy Spencer reports on the recent temperatures in the CONtiguous United States (CONUS).  What is missing from his report is the relevant context.  First, the CONUS represents just 1.6% of the Earth's surface.  So small a part tells us little about global temperature change.  It does not tell us, for example whether the very warm temperatures in parts of  Canada and Alaska (1.1%), or record breaking warm temperatures in Australia (0.6%) have balanced those in the CONUS or not.  It certainly does not tell us what is happening to the other 96.7% of the Earth's surface.

Second, Spencer is not reporting official United States Historical Climate Network (USHCN) figures, but his own figures which use a larger Urban Heat Island (UHI) adjustment than do the official figures.  While we cannot be certain as to the correct adjustment for UHI and other factors, recently the accuracy of the USHCN adjustments have been corroborated from an independent source.  

Third, he is only reporting on two winter months. Individual months are always more variable than annual figures, which have some of the variations cancelled out be averaging.  Consequently it is not surprising that a two month period should be unusually cold, even with the background of a warming trend.  It makes such comparisons mere curiosities, having no bearing on the long term change in temperatures.  Spencer shows a graph of his adjusted Integrated Surface Hourly (ISH) figures compared to the official USHCN figures:

It can be seen clearly that Spencer's adjustment significantly cools later years relative to earlier years. Indeed, by 2013, it cools it by 0.35 C.  As it turns out, that does not make a large difference in the ranking of 2013, which is the 13th coldest of 41 years in his adjusted figures, whereas it is tied for 15th and 16th coldest in the official USHCN data over that 41 years.  Of course, the USHCN has many more years on record than just 41, and most of them much colder.  Further, the early years of the 41 Spencer shows are obviously colder than the later years. Indeed, 8 of the first 15 years shown are colder than 2013.

 That brings to mind a recent comic by xkcd:

Which brings us to the December/January figures ;)

 In those figures, Spencer shows that Dec/Jan of 2013/2014 have indeed been cold relative to the last 41 years, being the 6th coldest out of 41 years data.   And it was indeed cold, at a chilly -0.55 C average for the CONUS.  Of course, relatively warm relative to the -2.1 C in 78/79. And the years before that were colder still.  What was commonplace has simply become note-worthy due to the warming climate.  XKCD has it right.

(Note:  This post is an edited and expanded version of an original comment at Skeptical Science.)

Saturday, January 4, 2014

Friday, November 15, 2013

Salby's Ratio in Hamburg

Just over a year ago, I drew attention to Murry Salby's efforts to suggest that CO2 was not a major contributor to ongoing warming in the twentieth century by the simple expedient of changing the scale ratio between two graphs that compared CO2 concentrations and temperature.  By greatly reducing the number of parts per million of CO2 in the scale relative to the degrees centigrade when comparing observations, Salby drastically increases the apparent slope of the CO2 observations relative to the temperature observations, thereby artificially creating an appearance of disparity where none exists.

I recently noticed the same two charts were used by Salby in his lecture at Hamburg.  Not only were the same two charts used, but much of the discussion was the same.  First he draws attention to the close match between CO2 concentrations and temperatures in model projections of the twenty first century, telling us that:
"Global temperature doesn't just increase with increasing CO2 - it tracks it, almost perfectly."

As in Sydney, having overstated the close relationship between temperature increases and CO2 increases in the model world, Salby goes to great lengths to draw attention to the disparity between the observed rise in CO2 and that in temperature - a disparity almost entirely created by his manipulation of scale ratios.  He says (1:02:00):
"In blue is the observed record of global temperature from the satellite MSU.  In green the observed record of CO2.  The long term evolution of temperature parallels that of CO2 during the 1980s.  It's been scaled to match the trend then, as was obtained by models of the IPCC.  With account of the eruption of Mount Pinatubo in 1992, their correspondence is similar during the 1990s.  But after the El Nino of 1997, CO2 continued to increase.  Global temperature did not.  Their divergence over the last decade and a half is now unequivocal."
(My emphasis) 
As can be seen by comparing with the transcript of his Sydney Institute lecture from a year ago (in my article linked above), that is almost word for word.  The only significant difference lies in the addition of the sentence which I have bolded; a sentence which purports to explain the choice of scale ratio.  That sentence is rather ambiguous.  It is not clear what Salby mean by it, and he nowhere specifies the method whereby he "scaled to match the trend".  More importantly, there is no interpretation of that sentence in which it is both relevant and true.

Saturday, September 28, 2013

Skeptical Science and the Lewandowsky Survey

Note:  This post was intended as a footnote for a later, longer post dealing with the Lewandowsky survey of 2010.  That has been much delayed, so I am publishing this now to clear it out of the way.

Some controversy has erupted over the claim that notice of Lewandowsky's survey on attitudes to climate change, the free market and a variety of conspiracy theories was posted on Skeptical Science.  As it stands, no internet accessible evidence dating from that time exists of such a post, although a tweet by John Cook notifying people of the survey on the 27th of August still exists.

Despite the lack of internet evidence, John Cook has claimed that a post was made on Skeptical Science in 2010.  His memory of the event is vague.  He initially was confused as to the year of posting, initially remembering it as 2011 rather than the correct 2010.  Further, he infers rather than remembers that the post was removed after the data was collected.  His memory that the survey was posted has been verified by Lewandowsky who has said,

"Hi Barry, the survey was done about 2 years ago, and I don’t have the link to SkS: I worked with John Cook directly at the time and; he posted it (and I made a note of it), but I don’t have the actual URL to the survey dating back to the time when he posted it.;I suspect he removed it when the survey was closed because then the link would have been dead."

Unfortunately the recollection of both Cook and Lewandowsky is faulty.  Following the method used by McIntyre I have examined the Way Back Machine record.  Rather than examining the home page as he does, however, I examined the much longer list of recent articles to be found in the "Latest Posts" in the sidebar.  Doing so for three dates (Aug 30th, 2010; Sept 8th, 2010; and Sept 23rd, 2010) provides a continuous overlapping record of Skeptical Science posts from Aug 17th to Sept 23rd that can be compared with the Skeptical Science Archive.  During that period, all articles listed on the Way Back Machine are still listed in the Skeptical Science Archives.

Monday, June 10, 2013

More Tol Gaffes

In a prior post, I examined how Tol claimed to find evidence that was "...indicative of the [poor] quality of manuscript preparation and review" in Cook et al, (2013) - evidence that upon examination consisted entirely in Tol's superficial reading of that paper.  Embarrassing enough, I guess, in a blog post, but that gaffe by Tol was in a "Comment" Tol was preparing for academic publication.  Tol is now in draft three of his comment, and has largely removed eliminated that blunder from the text. (He is still insisting that information from a co-author of the paper is irrelevant to his analysis.)  Draft three still contains several outright blunders, indicative of Tol's antagonistic intent and superficial analysis in his comment.  I examine two of those blunders below.