Off and on, I had been playing around with the global surface temperature data -- coded up a program to crunch the data via a simple gridding/averaging procedure that is much simpler and cruder than what the NASA/NOAA/CRU folks use, and discovered that it was amazingly easy (easy from a programmer's perspective, that is) to confirm the global temperature results published by NASA/NOAA/CRU etc.
So I put together a simple summary plot of some of my results, something that might be useful to hit vocal "skeptics" with:
The plot shows three global temperature curves, which I've deliberately left unlabeled.
One of the curves represents the official NASA/James-Hansen "meteorological stations" results (copy/pasted directly from the NASA/GISS web-site). Another of the curves shows results generated by my simple averaging program when I ran raw temperature data through it. And the final curve shows the output of my simple averaging program when I ran "homogenized" data through it.
So the approach here is, show the plot to your skeptical coworkers/relatives/etc. without telling them anything about how the temperature curves were generated, and get them to state what they see. Do the curves look very similar? Do they all show similar warming trends? Are the differences between them pretty minor? Get them to commit to answers to those (or similar) questions.
Then, once you've gotten them to stake out their positions, tell them how the temperature curves were generated, and them ask them if they can tell which curve is which.
Details about how each temperature curve was generated are supplied below the jump.
Also, a link to the computer source code is supplied below the jump (disclaimer -- not a finished product, not user friendly -- it's an off and on "hobby project" with some minimally-tested features).
1) The dark blue curve shows the official NASA results (copy/pasted from http://data.giss.nasa.gov/...).
2) The green curve shows the results my simple program produces from raw temperature data.
3) The red curve shows the results my simple program produces from homogenized temperature data.
Raw/homogenized data and all documentation are available here, BTW: ftp://ftp.ncdc.noaa.gov/...
Full source-code available here: http://tinyurl.com/...
A typical ideologically-driven "skeptic" response is to demand to see the code. If skeptics hit you with that demand, just say "right back at ya", give 'em the above link, and then watch 'em do nothing with it.
The take-home message here:
The official NASA/James-Hansen global temperature results are so similar to the results that my simple program produces from raw data that you almost need a magnifying glass to tell them apart. If James Hansen were really manipulating the data in some secret, underhanded way to get his results, then how was I able to reproduce his results so closely by running publicly-available raw data through a straightforward averaging program?
Data "homogenization" has a very minor impact on global-average temperature results. If scientists were "homgenizing/manipulating" data with the goal of faking or exaggerating the global warming trend, they did a pretty lousy job of it.
My suggestion is to transfer the image to your smartphone one way or another so that you can have it handy to "whip out" on a moment's notice. (Emailing it as an attachment to a gmail account is convenient -- the image will automatically display when you open the email message on your phone).