Climate Science Survey – the questions

In the spring of 2012, a large scale climate science survey was held amongst 6500 scientists studying various aspects of global warming. The survey was spearheaded by the Netherlands Environmental Assessment Agency (PBL), where I was responsible for the execution and analysis during the first half of 2012.

The objective of this study is to gain insight into how climate scientists perceive the public debate on the physical scientific aspects of climate change. More info about the survey was posted on the PBL website at the time, which has recently been updated to include a link to the survey questionnaire. Please note that the survey is no longer active.

Some confusion has arisen over the status of this survey. I responded at WUWT in an attempt to clarify:

We undertook a survey in March/April of this year (which, as Hans Labohm mentioned in a comment on WUWT, had been previewed by a variety of people with different viewpoints). Some respondents, e.g. Timothy Ball, asked to see the questions again. After internal consultation, we decided to publish the survey questions on the institute’s website, so that they are viewable to all. We contacted the survey respondents to inform them of the questions being available to view. I informed Dr Ball of this as well, to follow-up on my earlier email to him.

Our email to all respondents, informing them of the fact that the survey questions are available on the web, was apparently misunderstood to mean that we were again soliciting responses to a survey; this is however not the case. Roger Pielke Sr had already put a notice about the survey on his blog, which he has since updated after an email clarifying that this is an inactive survey, to which he had previously responded.

Below we (Bart Verheggen and Bart Strengers) reply to some of the more substantive questions regarding the survey questions raised on WUWT. However, we will not discuss results or the survey sample at this point in time. We will do so when our manuscript has been accepted.

Referring to question 1a

1a. What fraction of global warming since the mid-20th century can be attributed to human induced increases in atmospheric greenhouse gas (GHG) concentrations?
More than 100% (i.e. GHG warming has been partly offset by aerosol cooling)
Between 76% and 100%
Between 51% and 76%
Between 26% and 50%
Between 0 and 25%
Less than 0% (i.e. anthropogenic GHG emissions have caused cooling)
There has been no warming
Unknown due to lack of knowledge
I do not know
Other (please specify)

Ken Harvey asks (46):

Let’s say that I believe that the correct answer is 0. If I tick that box I immediately lump my opinion in with those who think that 25% is the appropriate answer, despite the world of difference between our positions. I am tempted to tick the next box down indicating less than 0% and I may, or may not give in to that temptation. Let’s sat that I believe that the correct answer is 25%. I face a similar problem – I don’t want to be lumped in with the fellow who thinks that the answer is 0. I am tempted to tick the higher box.

This is indeed a dilemma. An alternative which we considered is to ask the respondent to provide a percentage themselves (i.e. as an open numeric question). This however would ‘force’ the respondent to provide a number which, according to many, would create the impression of much higher certainty than there is about this estimate. (Can we really distinguish whether this contribution is 81 or 82%? [or 2 or 3% if you wish]). It is clear that both options have pros and cons, but we believe that by making enough –but not too much- ranges available, we obtain relevant information about the respondents’ thoughts.

Robert of Ottawa asks (66):

Question 2A asks: Has the trend in global average temperature changed in the past decade, compared to the preceding decades?
and offers the possible answer: The trend over the past decade is negative (i.e. cooling)
But question2b asks: What is your interpretation of the trend over the past decade with respect to the long term (multi-decadal) trend?
and does not offer the possible answer from 2A: “The trends are of natural cause”. Instead, it offers variants for Warmistas or don’t know.

Question 2 doesn’t go into causation (be it anthropogenic or natural); 2b is only about what the respondent thinks is happening to global temperatures on longer timescales. Eg the answer option to 2b “Long-term warming trend has changed as indicated by my previous answer” could be chosen to reflect the opinion that temps are cooling also on longer timescales.

A. Scott asks (72):

Would you share a bit more detail about what the goal of your survey is – what you hope to find from it.

The objective of this study is to gain insight into how scientists, who have published on global warming, perceive physical science issues, which are frequently debated in the public domain. E.g. by investigating the extent to which scientist agree or disagree about these issues (both the big picture issues and the detailed aspects)? How are these responses related to one another? What can we learn from that?

DaveA asks (79):

But still, this only covers questions pertaining to the direct influence/existence of AGW. Where’s the question asking how many climate refugees will eventuate from climate change? Food shortages, extreme weather fatalities, climate anxiety… so often that’s where the disagreement starts and where the label “denier” is pulled out even for those who have accepted an anthropogenic influence.

As explained on the PBL website regarding this survey, we decided to focus on physical science aspects of the public debate (mostly with a ‘skeptical’ signature): These ‘IPCC Working Group I’ topics are a focal point in the public debate and they form the foundations for further deliberation; for example, regarding impacts or response strategies. We chose to be as complete as realistically possible in covering the physical science aspects, acknowledging that that meant we could not include other aspects such as you mention.

Tim Welham asks (87):

This questionnaire is biased at Q1 and shows little professional attention to detail. I haven’t bothered to go further. As Ken Harvey points out in Q1 (we get no further) we see lower answer categories of:
Between 0 and 25%
Less than 0% (i.e. anthropogenic GHG emissions have caused cooling)
The design of this questionnaire forces anyone replying into categories which may not reflect their real view. There is absolutely no reason why a ‘Percentage: Please write in’ could be used to give the respondent an accurate reply. Then the final category ’caused cooling’ is junk. What can be less than 0%?. If it is 0% why should it cause anything in terms of cooling or heating?

More people may deem the survey too detailed rather than not detailed enough. For deliberations regarding an open question or offering ranges as answer options, please see above in our reply to Ken Harvey. There is no right or wrong there, but multiple options with each their specific pros and cons. However, by offering a wide range of answer options (even providing the option of answering that greenhouse gases cause cooling (i.e. a negative percentage)), we believe we avoided a bias a much as possible. One could actually make the argument that the answer options for question 1a have an inherent bias in the other direction, since the option that GHG by themselves are responsible for more than the observed warming (i.e. >100%; see e.g Huber and Knutti, 2011) has not been subdivided into multiple ranges.

Bart Verheggen and Bart Strengers

Advertisement

Tags: Bart Strengers, Bart Verheggen, climate change, Climate Science Survey, climate scientists, global warming, Netherlands Environmental Assessment Agency, PBL, public debate, questionnaire, survey