Montag, 3. Februar 2014

How to: Proper cherry picking

There is a much discussed graph in the blogosphere, which shall approve, that there is no delay  or pause or decline in global warming. Its from:

http://tamino.wordpress.com/2014/01/30/global-temperature-the-post-1998-surprise/

He states: Twelve of sixteen were hotter than expected even according to the still-warming prediction, and all sixteen were above the no-warming prediction:

HadCRUT4

Let get a larger picture:




  • We see the red HADCRUT4 graph, coming downwards a bit from 1960 to 1975, and inclining steeper beyond 2000, with a slight drop of about the last 10 years.
  • We see a blue trend, rising at the alarming rate of 0.4°C within only one decade! This was the time when some scientists started to worry about global warming.
  • We see the green trend, used by the blogger Palmino in the first graphic, rising less than 0.1°C per decade.
  • Below we see the Sunspot Numbers, pulsing in a frequency of about 11 years. Comparing it with the red temperature graph, we see the same pattern of 11 years pulsing. It shows clear evidence that temperature is linked to the sunspot activity.
Palmino started his trend at high sun activity and it stopped at low activity. Therefore the weak increase during 18 years.

Which leads us to my question of a former post: How long should a time be a time for observing climate change? If we only look at the sunspot activity and the clear pattern it produces in the temperature graph, the answer is: 11 years or a multiple of it.

Or we can measure from any point of:

  • high sun activity to one of the following
  • low sun activity to one of the following
  • rising sun activity to one of the following
  • declining sun activity to one of the following
To eliminate the pattern of sunspot numbers.

Let's try it out:


The last point of observation of the trend is between 2003 and 2014, about 2008. But even here we can see the trend has changed.

We do not know about the future. An downward trend seems possible, but a sharp rise is predicted from some others, which would destroy our musings so far.

Just being curious: How would the graph look with satellite data? Let's check RSS.


Really interesting. The top of both graph appears about 2003. HADCRUT4 shows a 0.05°C decline, RSS a 0.1°C per decade.

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