The Skeptical side claims at least 31,486 dissenters in their ranks, according to the PetitionProject.org. That sounds like a lot. But is it?

Of course, not all 12 million US scientists therefore agree with ‘The Consensus’. But this puts the PetitionProject’s 31,486 signatories in some kind of context.

Our maths here is somewhat coarse. Some better data suggests the ‘consensus’ figure is around 97.5% of publishing climatologists and around 90% of all publishing scientists supporting the human-induced climate theory. See this study for more details (PDF – Doran And Zimmerman 2009)

Actually, here’s how some of it looks:

Skeptical Field

Among the climate skeptic scientists, we wondered which fields of science were most represented. We expected climate and earth sciences. But we got…

In fact, when you adjust the PetitionProject’s odd categorisation – they filed ‘chemical engineers’ as chemists and physical engineers as ‘physicists’ – the total number of engineers who signed the petition, by our reckoning, jumps to 49%

Why so many engineers?

A visual map of the arguments for and against human-caused global climate change.

I’m fascinated by climate deniers. How could anyone deny the climate change is happening?
What evidence is there? Surely it’s unambiguous?

Curious, I investigated the key statements made by climate denialists and sought out the counter-views, as presented by climate research scientists. The result is this image.

(This a new and updated version of the spread on Climate Skepticism from my book The Visual Miscellaneum)

Method

I researched this subject in a very particular way. I deliberately chose not speak directly to any climate experts or leading scientists in the field. I used only publicly available web sources.

Why? Because I wanted to simulate what it’s like for people trying to learn about climate change online.

My conclusion is “what a nightmare”. I was generally shocked and appalled by how difficult it was to source counter arguments. The data was often tucked away on extremely ancient or byzantine websites. The key counter arguments I often found, 16 scrolls down, on comment 342 on a far flung realclimate.org post from three years ago. And even when I found an answer, the answers were excessively jargonized or technical.

Most of the info for this image is sourced from Realclimate.org. It’s an amazing blog staffed tirelessly by some of the world’s leading climatologists.

Unfortunately, the majority of the writing on there is so scientific and so technical, it makes the website nigh on useless to the casual, curious reader.

This has got to be one of the reasons why scientists and leaders are struggling to convince sections of the populace that the threat of climate change is real. Because they’re doing such a terrible job explaining it.

(Saying all that, I would like to express my gratitude to Gavin A Schmidt, one of unsung heroes of the web IMHO. His sterling and patient replies to comments, on RealClimate.org in understandable English, have really helped this process.)

Runaway Feedback

This image was a mammoth undertaking, especially for someone like me, unschooled in climate science. So I appreciate your understanding if any errors have crept into the process. If you spot any, please get in touch and I’ll will correct them on the double.

In every case, wherever possible, I went back the original data. (I’ve included a ZIP of all the data I’ve collected plus a spreadsheet of all the sources). And all the graphs in the image are generated from the original temperature records and other data sources. Feel free to rifle through and check everything.

RealClimate.org are (now) keeping an archive of all the data – if you want even more!
http://www.realclimate.org/index.php/data-sources/

UPDATE 1 (12th Dec 09): There have been a few complaints about the legibility of the image. So I’ve created a version on white instead of black.

A piece exploring the myths around 2012, Mayan Prophecy, geomagnetic reversal, The Long Count, consciousness shifts, Hunab Ku, galactica alignment, the Precession Of The Equinoxes, rogue planet Nibiru, solar storms, pole shifts, timewave zero, the return of Quetzalcoatl and THE END OF THE WORLD December 21st 2012!

Make up your own mind

UPDATE 1 (8 Dec 09): There’s now a Portuguese version of 2012 (thanks Ricardo Vieira) and a French version DEUUUUXMIIIILLEDOUUUUZE (thanks to Olivier!)