Archive for October, 2011

Graphing climate change: an activity examining persuasive graphing / writing

October 31, 2011

The New Scientist had a graph, reproduced below.  It struck me as a good teaching example, both as a source for examining the effects of presentation choices on interpretation and as a trigger for discussion on the distinction (if any) between persuasive writing and biased writing.

The  graph’s title as published was vague, as it related the graph also to an added range of possible effects  cut from this image.   I think of this graph as “Temperature increase in °C for given CO2 concentration, by climate sensitivity to CO2 in °C per doubling of CO2 level”


  • What does this graph show ?
  • How does it make you feel about increasing CO2 levels?
  • What title do you prefer at present?
  • Can you imagine the following re-graphing:

– Put temperature increase (the dependant variable) on the Y-axis and CO2 (the independent variable) on the X-axis  (This is, after all, the customary arrangement.)

– double the size of the scale for Atmospheric CO2, so that “100” is as far from the zero point as “200” is at present;

– place the in-graph  labels for “likely Scenarios” “Outside possibilities” and “most likely scenario” so that they  are in the same visual spaces as in the original.

  • Make the new graph you tried to imagine.   It does represent the same data.  Look at it:
  • What title would you give it?
  • Does it make you feel the same way about increasing CO2?
  • Compare the two graphs.  Which do you prefer?  Why?
  • New Scientist has been accused of being biased  in its presentation of the science concerning climate change.   Does the published graph  cross the line between science reporting and biased writing?
  • Is there a distinction between persuasive and biased writing?
  • Is there /should there be  a line between science reporting and persuasive writing?  Why / why not?