Skeptical Real Climate Science

"Hiding the Decline"

Here's a go at explaining "hide the decline" to newcomers as well as looking at the continuing tricks.
Please correct me if I've got it wrong.

At the bottom of this UEA December 1st release are two graphs. The first graph was prepared for the WMO (World Meteorological Organization) for 1999. It shows three separate proxy temperature reconstructions (from Jones et al 1998, Mann et al 1999, and Briffa 1999). Each proxy mix is smoothly, seamlessly spliced to the thermometer record. The second graph (white background) looks like it has been prepared in a hurry... now it separated the coloured proxy curves from the black temperature curves.


Superimpose the second graph (white background) on the first to glimpse the differences	Home in closer - the first is to "hide the decline" but - oops - the decline is clearly there in all recons when the thermometer records are separated out.

Home in still closer to see seven "tricks" - at the very least, tricky-misleading - when the new graph lines are overlaid on the 1999 WMO chart. Look carefully: the new proxy lines, uncontaminated by the thermometer record, are lighter shades of colour.
(1-3) Each proxy record starts to show a decline that has been hidden by absorbing the thermometer record: the red (Jones) and the blue (Mann) from 1970-ish on, the green (Briffa) from 1950 on.
(4) The splices used in the original graphs SOAR up to year 2000 - to outdo both the proxies and the thermometer record.
(5) The original is said to be anomalies from 1961-1990 baseline. But looking at the 1961 and 1990 lines, this baseline looks way too low.
(6) There are TWO black temperature lines. The notes say instrumental temperatures (annual & summer in black) shown separately - but why annual and summer? Now summer/tropical anomalies are always less extreme than winter/polar anomalies. Is it possible that the summer record was brought in to smooth off the inconvenient dip from 1940 to 1970 - but then the annual record was restored "spliced" post-1990 in order to help raise the final point? Or was the winter record used to achieve those stunning heights that exceed both summer and annual?
(7) The hidden decline is revealed and can now be set in context against the original WMO graph.

The "decline" is now truly "hidden in plain sight" thanks to Steve McIntyre's work on the new CRU data. See web page when not busy.	Finally, this is from the CRU code file osborn-tree6/briffa_sep98_d.pro (see below). Was this another "trick" used to "hide the decline", or perhaps to elevate global temperature records?

From the CRU code file osborn-tree6/briffa_sep98_d.pro , apparently used to prepare a graph purported to be of Northern Hemisphere temperatures and reconstructions:

;
; Apply a VERY ARTIFICAL correction for decline!!
;
yrloc=[1400,findgen(19)*5.+1904]
valadj=[0.,0.,0.,0.,0.,-0.1,-0.25,-0.3,0.,- 0.1,0.3,0.8,1.2,1.7,2.5,2.6,2.6,$
2.6,2.6,2.6]*0.75 ; fudge factor
if n_elements(yrloc) ne n_elements(valadj) then message,’Oooops!’
;
yearlyadj=interpol(valadj,yrloc,timey)

In addition, this website, found by AJStrata, shows the following post which amplifies the context further:-

# JonB Says:
November 25th, 2009 at 3:19 am

I’ve been trying to puzzle out for myself what this code is actually trying to do. My IDL-fu is effectively non-existant however…

If you expand ESRs original quote a little bit you get…

plot,timey,comptemp(*,3),/nodata,$
/xstyle,xrange=[1881,1994],xtitle='Year',$
/ystyle,yrange=[-3,3],ytitle='Normalised anomalies',$
; title='Northern Hemisphere temperatures, MXD and corrected MXD'
title='Northern Hemisphere temperatures and MXD reconstruction'
;
yyy=reform(comptemp(*,2))
;mknormal,yyy,timey,refperiod=[1881,1940]
filter_cru,5.,/nan,tsin=yyy,tslow=tslow
oplot,timey,tslow,thick=5,color=22
yyy=reform(compmxd(*,2,1))
;mknormal,yyy,timey,refperiod=[1881,1940]
;
; Apply a VERY ARTIFICAL correction for decline!!
;
yrloc=[1400,findgen(19)*5.+1904]
valadj=[0.,0.,0.,0.,0.,-0.1,-0.25,-0.3,0.,-0.1,0.3,0.8,1.2,1.7,2.5,2.6,2.6,$
2.6,2.6,2.6]*0.75 ; fudge factor
if n_elements(yrloc) ne n_elements(valadj) then message,'Oooops!'
;
yearlyadj=interpol(valadj,yrloc,timey)
;
;filter_cru,5.,/nan,tsin=yyy+yearlyadj,tslow=tslow
;oplot,timey,tslow,thick=5,color=20
;
filter_cru,5.,/nan,tsin=yyy,tslow=tslow
oplot,timey,tslow,thick=5,color=21

I read this as being responsible for plotting the ‘Northern Hemisphere temperatures and MXD reconstruction’.

Note however the commented out code. The way i’m reading this, any graph titled ‘Northern Hemisphere temperatures, MXD and corrected MXD’ with a thick red line released before the brown matter hit the whirly thing probably has cooked data. Likewise if you see a thick blue line you might be ok.

Where do i get thick red line from?

According to the IDL Reference Guide for IDL v5.4, thick=5 means 5 times normal thickness. and color=21 links to (i believe)

def_1color,20,color='red'
def_1color,21,color='blue'
def_1color,22,color='black'

from just above the code segment itself.

However there’s one thing that i’m not sure about without either being able to play with IDL or seeing the end graph. It does actually plot the uncooked data in black (oplot,timey,tslow,thick=5,color=22) so whats the point of showing a cooked data line along with the uncooked dataline? Not to mention that the uncommented version apparantly prints the same data series twice.