ARE PEOPLE THE CAUSE OF CLIMATE CHANGE?
"Here's a hypothesis:

People's activities are a major cause of global warming.

We'll call it the 'hypothesis of anthropogenic global warming'!

'Anthropogenic' means 'caused by people'!"

"I don't get it, Lulu! How do people cause global warming!? Explain, please...!"
"Sure! First, take a look at the way the hypothesis is commonly presented. Click on the red button and go to the 'Common Presentation Rollover'!"

       THE 'COMMON PRESENTATION ROLLOVER'

"Now I get it! I see the link between what people do and the temperature of the atmosphere! So, if the 'anthropogenic hypothesis' is true, then if people change their ways, maybe dangerous global warming can be avoided!"
"But there's a problem with the way the hypothesis is commonly presented, Lou! As you can see in the 'Common Presentation Rollover', there's no distinction between observations (supposed 'facts') and proposed causes! Everything is presented as part of an unquestioned chain of cause-and-effect relationships! Let's break the hypothesis down into separate steps that distinguish between what scientists have observed and how they explain things! Click on the red button and look at the 'Reformulated Anthropogenic Hypothesis Rollover'!!"

       THE 'REFORMULATED ANTHROPOGENIC HYPOTHESIS ROLLOVER'

"Sounds much more scientific now!""So far so good, Lou! Much of this line of reasoning and the evidence for it is incorporated in the documents produced by the Intergovernmental Panel on Climate Change (IPCC), which is a United Nations sponsored organization! And the Kyoto Protocol, which draws on IPCC results, is an agreement amongst different countries as to how to go about reducing the production of carbon dioxide and other greenhouse gases!"
"The only problem Lou is that there's disagreement about many of the steps in the argument we've outlined, about whether the IPCC has got it right, and about whether the steps suggested in the Kyoto Protocol will be helpful or harmful!! Remember, if any of the links in the chain of reasoning break, the whole hypothesis could fall apart!"
"So we need to look at the questions raised for each of the nine steps leading to the hypothesis!" "Right on, Lou!!! Let's review the steps and see what the questions are!! Click on the red button!"

       THE 'QUESTIONING THE STEPS ROLLOVER'

"So there are questions raised about the validity of both the observations and the proposed causal relationships! Wow, that's serious!! It's all getting very complicated!!!" "We'll try to simplify things, Lou! To get at the heart of the argument, we can rearrange and clump some of the steps together, rephrase the questions, and look at some important, relevant comments!"
"Anything to make it simpler is OK by me! Carry on, Lulu!"

       THE 'CONDENSED FOUR-STEP HYPOTHESIS ROLLOVER'

"So there are four major questions! If the answer to any of them is 'NO', then the hypothesis of anthropogenic global warming is greatly weakened!"

THE FOUR QUESTIONS BOX
1. Is it a 'fact' that over the last 200 years or so, F, aCO2, tCO2, and T have all risen?
2. Is there really a 'Greenhouse Effect' operating in the atmosphere?
3. Is the Greenhouse Effect important compared to other causes of global warming?
4. Is intensification of the Greenhouse Effect mainly due to people's activities, rather than to natural causes?
IF ANY OF THE ANSWERS TO ANY QUESTION IS 'NO', THE CHAIN IS BROKEN

"Wow! Tell me, Lulu, is the anthropogenic global warming hypothesis in deep trouble?! Or is it right on the mark!? How can we tell?!" "There are lots of organizations that are concerned about the possibility of climate change, Lou! Let's look at a few of them and see what answers they give to those four questions! Click on the red button and visit the Position Panel!"

       THE 'POSITION PANEL'

"Now we understand what each of these organizations thinks about global warming!! We also know the degree to which there's agreement as to the correct answers to the four questions! But who's right???! And what are the REAL correct answers?!" "Well, Lou, we're not global warming experts! We can't say whose science is right and who's science is wrong! But there is something else we can do!!"
"What's that???!" "Perhaps we can come to some conclusions as to the reliability of each of the organizations!! We can set up 'reliability criteria' for judging sources and the information they give us! Click on the red button to see the criteria!"

        THE 'RELIABILITY CRITERIA'

"Unreliability can be subtle! Sometimes conclusions are drawn based on information that is presented in the form of graphs! Graphs tend to make information look scientific, but graphs can be used to manipulate opinion! When judging reliability, look carefully at how graphs are used! Click on the pink button marked 'P' to print out instructions. Click on the red button to learn more about how graphs manipulate opinion!"

       INSTRUCTIONS FOR THE GRAPH MANIPULATION EXERCISE (GM-1)

       THE GRAPH MANIPULATION EXERCISE: HOW GRAPHS MAY BE USED TO MANIPULATE OPINION

"Now, let's see some examples of applying 'reliability criteria'!! Go visit the Reliability Panel Menu!"

       THE 'RELIABILITY PANEL' MENU

"I don't know about you, Lulu, but I'd like to see if we can draw some conclusions about whether people have been causing a change in the climate!!""I think we can, Lou! I think we can!"

       THE 'CONCLUSIONS PANEL' MENU

©2003
David J. Leveson & Wayne G. Powell