The claim cannot be seen as anything other than deliberate deception. But truth is always a casualty to the needs of the Green/Left
Study claiming ’97% of climate scientists agree’ is flawed
Perhaps the most common argument used when urging action on climate change is the appeal to scientific authority. Previously this was accomplished by pointing at the IPCC, but since they have lost a significant portion of their credibility recently it has become more frequent to point out the scientists themselves. The most common claim that I encounter is a variation on this claim:
97% of climate experts agree humans are causing global warming.
I recently heard this claim on my own threads. I looked at the source (the study Doran and Zimmerman 2009), found some problems, and then wrote back on my threads. However, I have seen this claim so many times that I believe it would be good to make a post about it. I also e-mailed several prominent climate scientists who would be considered 'skeptics' to get their opinions on the study. Their responses are displayed at the end of the post.
In this post I briefly comment on past responses to the study, then break my post into three sections. The first will focus on the flaw in the study (the second question), the second will look at the motives of the researcher, and the third will be posting responses from prominent 'skeptical' climate scientists.
First I'm going to address a common response to this study. In this post at The Hockey Schtick, it is pointed out that the 97% statistic is based on only 79 climatologists, and that those participating were self-selected. There are two concerns here. The first is sample size. While climate science isn't a massive field, 79 participants is fairly small. To claim definitely that 97% believe this or that you would need to poll significantly more people. The second concern is the fact that the scientists were self-selected by an online survey. This may not have led to a representative sample.
Other concerns with the study deal with numbers behind it, or other reasons to consider it a poor study. However, these aren't my primary concern. My concern is the actual questions asked in the study, which I will show in a moment.
The study on which these claims are based is available here. It is an paper by Peter Doran and Maggie Kendall Zimmerman written in 2009, entitled "Examining the Scientific Consensus on Climate Change". Here is the citation:
Doran, P. T., and M. Kendall Zimmerman (2009), Examining the Scientific Consensus on Climate Change, Eos Trans. AGU, 90(3)
The study is fairly simple. It has a large database of earth scientists, and sends them an invitation to participate in their study. If they accept, then they take an online survey. The survey asks two primary questions:
1. When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?
2. Do you think human activity is a significant contributing factor in changing mean global temperatures?
The first question is largely irrelevant. I'm unaware of any scientists who don't believe the planet has gotten warmer when compared with pre-1800s levels. Not surprisingly, 76 of 79 climate scientists answered 'risen' to this question. I'm guessing that the other three didn't consider the increase significant enough to warrant 'risen' and picked 'constant'.
The major problem with this study is the second question. It is not phrased properly. In fact, the phrasing is so poor that I consider the entire study flawed because of it. There are multiple problems with the phrasing, so let me break them down.
1. The phrase "human activity"
Human activity comprises numerous actions which can affect the climate other than greenhouse gases. Agricultural changes and deforestation are two influences that come to mind. Now, any respondent who believes that ANY human activity can change the climate must answer yes to this question.
A better phrasing would be:
Do you think anthropogenic greenhouse gas emissions are a significant contributing factor in changing mean global temperatures?
2. The phrase "significant contributing factor"
The problem with this is obvious. What makes something significant? If 5% of recent temperature change is caused by mankind, is that significant? How about 10%? There is no context for answering the question. There is no way of knowing whether or not the respondents consider human activity the primary factor in temperature change.
A better phrasing would be:
Do you think that anthropogenic greenhouse gas emissions are the primary factor (50% or more) in changing mean global temperatures?
3. The phrase "changing mean global temperature"
This is the most problematic part of the question, because there is no indication of how much temperature change is considered worth answering 'yes'. For example, if a respondent believed that human activities had increased the temperature of the planet by 1/10th of a degree, the answer would still be yes. Even so for 1/100th. There is no useful context here. Many climate skeptics believe that human activities have increased the temperature of the planet, but not by any significant amount. The survey should specifically ask if the warming is a statistically significant amount. Also, the word "changing" should be changed to "increasing", because otherwise a respondent could consider human activities as cooling the planet and still answer yes.
Much more HERE (See the original for links)