Friday, 4 July 2014

Facebook and the temperature Pause.

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.

No comments:

Post a comment

All serious comments published after moderation.
Comments should be polite, and respect all views.
No bad language. Spam never makes it!