by Anthony Cox
In another post I had referred to some good graphing work by
Shea
Lewis. This time Shea has responded to a criticism of the temperature pause
graph prepared and regularly updated by Lord Monckton:
A Facebook poster in the customary Alarmist way has prepared a graph allegedly debunking this pause:
The graph is from RSS data. RSS compares its data by
reference to a baseline. The baseline is the reference period of years which is
used to compare particular years and periods of temperature both within the
base period and outside it. RSS uses a base period of 1979-1998, or 20 years.
The mean of the base period for purposes of comparing other
years or periods must be zero since it is the reference period. Other years or
periods which are above or below that period are described as having anomalies
referable to the base period.
Monckton’s pause covers the period from 1997 up to the
present. The method for determining this pause is described by Werner
Brozek. Brozek uses the same method employed by both Skeptical Science and
Phil Jones from UEA. You go back from the present in the data to the furthest
month from the present with a negative slope and then see if that trend is
continued from the next month to the present.
It is a straightforward statistical technique for
established trends to the present. Currently RSS is 17 years and 10 months as
Monckton’s graph shows.
What has confused and angered the Facebook poster is that the period of
the temperature pause is warmer than the base period. But this is comparing
apples and oranges and we see this in the equally fallacious alarmist claim
that each decade is warmer then the next.
This is plain from the graph of RSS data in the decades from
1980 to 2010. The 2010 decade is still hotter than the 1990 decade but has a
declining trend. Which contradicts AGW.
So with the temperature pause. The temperature mean of the
period in which temperature has paused is warmer than the RSS base line mean.
But the temperature has stopped rising. Which again contradicts AGW. Shea’s
graph clearly shows what is happening:
The RSS base line is in red. The temperature pause is in
black. The temperature has stopped rising at a higher temperature than the base
but it has stopped rising. The blue line still shows an overall upward trend
over the whole period from 1979 but that is misleading because for 50% of that
period temperatures have not been rising. All the temperature rise took place
before 17 years and 10 months ago. In fact David Stockwell and I showed that
all that rise happened from 1976
to about 1979.
Another nail in the AGW coffin.