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the main claim put forward in the movie An Inconvenient Truth that the earth is getting warmer as a result of human activities is largely based on one particular graph, depicting the variation in temperature compared to the levels of carbon dioxide in the atmosphere over the last 1,000 years.

naturally, this particular graph was subject to a great deal of controversy.

"Not only has the data been under the microscope, but the way that the data is represented has been minutely dissected... An article published by the conservative think tank the Heartland Institute calls the slide in Gore’s film, “A triumph of data manipulation.” Among other criticisms, the article claims that you can’t tell whether warmer temperatures precede or follow the rises in levels of carbon dioxide and that the scale along the vertical “y” axis is not clearly labeled. Rarely has an example of design been subjected to such intense scrutiny at every level from so many sources.".

an alternative graph was offered by critics of global warming in an attempt to show that temperatures are not, in fact, on the rise.

[link: (overview) & (original critical article) &]






Even though there may have been warmer periods than we currently have, the graph still clearly shows that there is a relationship between temp and CO2.

In that sense, it doesn't really matter what range of values the y axis for temperature represents; the lines match so well!! (Assuming that the x axis is indeed correlated correctly).

(Nice to see a company like Adobe paying attention to infovis).

Wed 07 Feb 2007 at 7:02 PM

The "critic" you link to at is simply incorrect. He wrote:

"Viewers also can’t see the scales Gore is using for his graph. Carbon dioxide concentrations have increased over time, but by only 87 parts per million since 1870 (according to the United Nations Environment Programme). If the vertical scale of Gore’s graph started at zero, the increase would have been too small for viewers to see."

That's just plain wrong, as one can see from the scale on your illustration. Current CO2 concentration is around 380 ppm; the rise of 87 ppm is easy to see.

Yes, the zero line of Gore's slide would have been a few feet below the floor, but this is irrelevant to his point. We care about absolute change for things that affect us absolutely: increased spending of $100 is significant for a weekly food budget but not for the federal budget. Who cares where the zero-CO2 line is? I don't demand that I live in an atmosphere completely scrubbed of CO2, nor was that the original state of the planet.

CO2 concentration is only significant because of its correlation with temperature, and Gore lays out that scale clearly and dramatically: the top is the climate today, and the bottom is ice age. I'm well aware of how to lie with statistics, I have a keen eye for errors like the missing zero line, and I thought this portion of An Inconvenient Truth was excellent work.

Surely the film has flaws, but this is not one of them. And there are probably cogent critiques of the film, but the page -- which seriously suggests Gore is wrong because his writings might be mistaken for Ted Kaczinski's -- is not one of them.

Thu 08 Feb 2007 at 1:02 AM

Maybe the first thing to note in distortions is that the Al Gore graph covers 650,000 years, while all the other graphs included in the critique and the report are covering 1000 years.

The whole point of the Al Gore slide (Similar graph here). The adobe article says Figure 1 is the 'original hockey stick graph.' This seems to imply that Al Gore's slide is based on Figure 1's data, when actually it comes from another study.

Thu 08 Feb 2007 at 2:40 AM

The ease with which interested parties can spread doubt about scientific results suggests to me that we need better scientific and numerical literacy.

The Heartland institute's critique of the data is both vague and unsubstantative; their only valid concern is about whether CO2 changes precede climate changes. I'm a little sad you dignified it with a link; surely there is a more rigorous critique available?

Thu 08 Feb 2007 at 3:21 AM

This is the hockey stick argument... which has been effectivly dismissed.

Check out realclimate for expert commentary from real climatoligists aimed at the general public.

Thu 08 Feb 2007 at 3:31 AM

Steve: Thanks for the mention of But what do you mean the hockey stick has been "effectivly dismissed?" Realclimate seems to have no problem with the general data, but only with specific misinterpretations of it:

Thu 08 Feb 2007 at 4:23 AM


the goal of the post was to make people aware of the critique on the infographics (while avoiding discussing the scientific or climatologic merit of the data). as has been pointed out, that one infographics was the primary tool for convincing people.

posting the Heartland link does not mean I am endorsing them, but might clarify how weak the opposition, and how good the infographic design actually is?

nevertheless, the infographics could be critiqued, as some other commenters pointed out.

Thu 08 Feb 2007 at 8:50 AM

Thanks so much for posting a link to my article on the Adobe site. The purpose of the article was to point out that the debate over global warming is being played out through infographics...and that, sometimes, discussion of the graphics themselves overwhelms discussion of the data they represent. By entertaining questions about the Gore graphics, however, I am certainly not questioning global warming. Interestingly, though, the graphics (that I could locate) created by opponents of global warming were not very compelling (others may find better example and I would love to see them). So the doubters are losing the graphics least for now.

Thu 08 Feb 2007 at 9:01 PM

The "hockeystick" graph is a temperature reconstruction based on proxy measurements. It is not a CO2 vs Temperature graph. There are CO2 vs temperature graphs around though.

You may find this site interesting:

Fri 09 Feb 2007 at 4:20 AM

Manipulative infographics aren´t much of a new topic. Picking this particular one, this rare successful bit of infotainment/documentary that actually makes people aware of climate change is a bit disappointing to me. Now the seeds of doubts are planted again and politicians have food for ignorance-propaganda. Not very desirable in my opinion. Especially as the data displayed is neither wrong nor manipulative.

Sun 11 Feb 2007 at 10:58 AM

martin, there's a difference between discussing the role of infographics in political debate and casting doubt on the data! the idea that anything that calls attention to the interpretive nature of information visualization is somehow a threat to the cause of global warming is both confusing and troubling to me. it seems to be a fundamentalist perspective that rejects any interpretation.

Tue 13 Feb 2007 at 1:46 AM
david womack

I do think David formulated it nicely. we should be aware of the critique on infographics, whether it is climate change or not (which otherwise could be understood as censure?).

the original article and the comments on the post clearly demonstrate the value of this particular graph, and the weak argumentation of the 'non-believers'.

I can only hope researchers, politicians and government agencies will learn from this example, and start to present data in an understandable, but also engaging, way to the masses.

Tue 13 Feb 2007 at 12:47 PM

i am from a lego robotics group.This year are challenge is over climate change.I need the most acurate information and the most belivable facts.Our team needs good facts and graphs.Belive it or not we had a actual scientist come in and he talked to us about climate.If you could kindly send any updates on climate or any graphs and facts please send it to my e-mail.THANK - YOU!

Sat 15 Nov 2008 at 10:29 AM

i am from a lego robotics group.This year are challenge is over climate change.I need the most acurate information and the most belivable facts.Our team needs good facts and graphs.Belive it or not we had a actual scientist come in and he talked to us about climate.If you could kindly send any updates on climate or any graphs and facts please send it to my e-mail.THANK - YOU!

Sat 15 Nov 2008 at 10:29 AM

I think one of the points being made is that the chart used by Gore does show a correlation between CO2 and temperature, but not a clear causal effect to make the statement that the CO2 caused the temperature rise.

Perfect eample - plant life. Plants use CO2 and if a sudden rise in temps caused a negative flexuation in plant life, this could lead to higher CO2.

It's the old chicken - egg story.

Also, one need only look at the last 9 years. Average global temps have remained relatively constant, yet CO2 has levels have increased.

Mon 29 Jun 2009 at 3:05 AM

If global warming is caused by co2 as the graph goes up is global cooling caused by it when the graph goes down? How does 500 ppm co2 cause global heating and then a few hundred years later cause cooling?
The only conclusion I can reach is that heat causes co2 to go up cooling causes co2 to go down. Heat is the leading indicator. co2 is the laging indicator!!!

Fri 17 Jul 2009 at 11:01 AM
JOHN Cronin
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