Song for Jasmine

Climate Change in the American Mind was published in March 2009. It contains the results of a survey of Americans conducted during September and October 2008. The report is 56 pages long, and is packed with information. Not surprisingly, it has been talked about on the web. Unfortunately, some of the information from it has been summarised in a very misleading manner.

One particular question asked Americans how much they thought global warming would harm different groups. They were asked to decide which option (not at all, only a little, a moderate amount, a great deal, or don’t know) applied to a number of different groups:

• you personally
• your family
• your community
• people in the United States
• people in other modern industrialised countries
• people in developing contries
• future generations of people
• plant and animal species

The results are presented on page 30 of the report, figure 22. Nate Silver summarised the answers to this question on his blog, in “The Environmental Inverted Pyramid“, but the picture he presents there (reproduced here) is misleading.

There are several things wrong with this picture. I won’t be the first to point out that the size of each segment is not in proportion, others have already done that (e.g. “The environmental inverted pyramid, corrected“). Even so, it’s worth looking at some of the other ways that this picture is misleading.

First, let’s make the bars to scale. There, that’s better. Now you can see quite clearly that the narrowest bar (‘you’) is genuinely half as big as the largest. Not that steep a pyramid at all.

There’s also an issue with the size of the text. Putting ‘you’ in tiny letters makes it seem unimportant compared to the large text for ‘plant and animal species’. So let’s make all the letters the same size.

There. I don’t know about you, but that looks a lot fairer to me! So it looks like only 1 American in 3 thinks global warming will affect them, and 2 out of 3 don’t think it will.

Ah, but we’re not done yet. New Scientist points out that we’re actually using the wrong data! These numbers represent only the ‘moderate amount’ and ‘great deal’ categories. If we want to see how many people do or do not think they will be affected by global warming, we should not forget that some of those people think global warming will affect things ‘only a little’.

‘only a little’ is not very well defined. It could mean they don’t think they will be able to go on holiday because of more hurricanes in their favourite resort, or that they think they will have to pay more for food or water. I have no idea what those people who said ‘only a little’ thought, but I do know that we can’t simply ignore them. That would effectively put them in the ‘not at all’ category, which is wrong.

So let’s add those people to the chart, and see what it looks like.

Now it hardly looks like a pyramid at all! In fact, the categories ‘you’, ‘your family’, and ‘your community’ are very closely grouped, as are the categories of ‘people in the United States’, ‘people in other modern industrialised countries’, and ‘people in developing countries’. The question might as well have been simplified to ‘people near you’ and ‘everyone else’.

So we can safely say that over half of Americans believe that someone near them will be harmed by global warming, and almost 2 out of 3 believe that someone, somewhere, will be harmed, even if only a little. If you’re among the remaining third, you could do worse than to read “Bracing For Sea Change“, to see how easily climate change could affect the world around you.

The full report contains 39 charts, and looks to have a great deal of interesting information in it. I haven’t read it all yet, but I will do so soon. Even on a quick scan through, there are some interesting nuggets that are easy to find. For example, 82% of Americans think they need more information about global warming (figure 33), 82% of Americans would trust scientists for information about global warming, and 77% would trust their family and friends (figure 39). That tells me that the scientists and other people among you who are concerned about global warming need to speak up more, 4 people out of every 5 out there would listen to you. Go to it, people!

Finally, let me just quote a few of the highlights from the executive summary:

All that seems to me to be a long way from the tiny triangle at the bottom of the inverted pyramid.