Slides 20 thru 24 show graphs of temperature versus time. This is compared with normalized "solar activity" from data Merchant has obtained. The time scale is from 1860 to 2000 but with data only to 1980 as per the Great Global Warming Swindle.
Slide 20 shows the raw annual data. Slide 21 shows data smoothed over 11 years. Slide 22 shifts the early part of the graph leftward (earlier). Slide 23 shows the data distorted by filling in the gap in slide 22. Slide 24 is the smoothed data of slide 21 but thru to 2000.
Smoothing is a valid procedure so long it doesn't show something contradictory from the unsmoothed data. If one wishes to show trends then some types of data will need to be smoothed. All data has some smoothing (though in a slightly different way). If you present monthly temperatures they are averaged daily temperatures (a smoothing phenomenon). The smoothing done here is more than using a different time division (day versus month), it is taking in to account data either side so 11 year smoothing is taking the year plus the five years either side and averaged while presenting the data in yearly divisions.
Massage?This is a serious charge. If they have manipulated their data, that is unacceptable and it would be helpful for the presenters to be clearer on the source data. However it seems that Merchant has misunderstood the source data as he now acknowledges.
- Convincing apparent correlation of solar activity and global temperature
- Has data been manipulated
- Data shown stop at 1980 .. when any correlation dramatically breaks down
- Method of persuasion:
- Selective use of data
Not showing data further than 1980 is not honest if there is a difference. The presenters should have shown it. But this doesn't disprove their theory; Merchant came up with an auxiliary theory (particulate matter) for the unexpected cooling, the solar advocates may have an auxiliary theory.
It is interesting he condemns the solar data for misrepresentation, yet how long was the hockey stick graph used? and how many people did it influence? and how much is it still used? despite its validity now being questioned by proponents and opponents.
Further, the sun hypothesis is just another theory to explain warming. It untrue it does not affect the critiques of global warming.
Now scientists are suggesting global warming on Mars; this gives the sun hypothesis increased credibility if one subscribes to Ockham's razor.