Online Resource 3
Article Title: The unseen uncertainties in climate change: reviewing comprehension of an IPCC scenario graph
Journal Name: Climatic Change
Authors: Rosemarie McMahon (1), Michael Stauffacher (2), Reto Knutti (3),
(1) Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland. Email: [email protected]
(2) Institute for Environmental Decisions, ETH Zurich, Switzerland. Email: [email protected]
(3) Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland. Email: [email protected]
Sample selection and recruitment
The readership of the SPM is very broad, however for the purpose of this study we relied on the definition provided by
the IPCC and the literature. Four main groups were defined; climate scientists, decision makers, communication experts
and academics. Decision makers were recruited from parliament, government agencies, and non-governmental (NGO)
agencies. In Switzerland, NGOs were included in the group of decision makers as they have an impact on political
decisions, by direct interaction with legitimate decision makers and by being consulted in legal procedures
(Vernehmlassungsverfahren), however we accept this might not be the case in other countries. Likewise, we class
climate scientists as experts in this study, however there exists other technical experts which have not been included in
our sample, for example, negotiators in the IPCC plenaries but who can also be classed as experts. While this sample is
informative we acknowledge that the group selection may not fully represent the broader readership of the SPM and
therefore the results can only be extrapolated to this sample.
In a second recruitment round we attempted to increase the number of interviews with decision makers and
communication experts however due to the limited pool we were unable to increase the size substantially. As climate
scientists had excellent knowledge of this graph there was no need to increase the number of interviews further. All
interviews were conducted up until the point of saturation, which is accepted in qualitative studies as the point in time
“when the collection of new data does not shed any further light on the issue under investigation”, please refer to Mason,
2010. While some groups might seem small, overall the sample size of 43 is quite a large sample for a qualitative study.
As we are not interested in frequency distributions but rather the different patterns of understanding this sample size is
considered robust.
Demographic Profile
Details about the professional background, nationality and attitudes towards climate science, the IPCC, and this graph
were collected for all 43 participants. This information was gathered from Task 1, 24, 30 and 34. Please refer to Online
Resource 1 for the full description of interview tasks.
1
The study group composition
Academics were the predominant group in this study followed by decision makers, communication experts and the
smallest sample climate experts, see Chart 1 below.
Climate Experts, 7%
(n=3)
Decision Makers,
23% (n= 10)
Academics, 49%
(n=21)
Communication
Experts, 21% (n=9)
Chart 1: Percentage of study participants (N=43) per group
2
Nationality
All decision makers were Swiss, whereas communication experts were from Europe decent and the academics were an
international group.
Education Background
The average years of experience ranged from 4 to 30 years with an average of 14 years with a minimum of 4 years and
a maximum of 30 years. The majority of participants had a doctoral level of education (n=19), followed by a Masters
(n=12), Professor (n=9), Degree (n= 2) and Diploma (n=1). Thus, the whole study group could be considered highly
educated.
The disciplines represented in this sample were mostly from natural science, mathematics and engineering fields (n=17),
followed by economics and political science (n=6). The below chart 2 illustrates the disciplines represented in this
sample. Decision makers mainly came from the discipline of natural science, mathematics, and engineering (n=7) and
only two came from Arts and Literature and the remaining from economics and political science. Almost half (49%) of
the academics were from the natural science, mathematics and engineering field.
Journalism,
Communication , 12%
(n=5)
Climate Science, 7%
(n=3)
Graphic Design , 5%
(n=2)
Neuroscience,
Psychology, Social
Science , 7% (n=3)
Natural Science,
Maths, Engineering ,
39% (n=17)
Arts and Literature ,
9% (n=4)
Computer Science , 7%
(n=3)
Economics, Political
Science , 14% (n=6)
Chart 2: Percentages of participants per discipline sector
3
Confidence in the graph data
When asked how confident they were in the data represented in this graph, most (n=17) were very confident and only a
few academics (n=3) were not confident at all. The majority (n=9) of decision makers were very confident in the data
represented, see Figure 1 below.
18
Not confident at all
16
Low level of confidence
Indifferent
14
Confident
12
Very confident
10
8
6
4
2
0
Total (n=40)
Decision makers (n=10) Communication experts
(n=9)
Academics (n=21)
Figure 1 Confidence in the graph data by group
Confidence in the IPCC organisation
When asked how confident they were in the IPCC organisation they were mostly confident (n=21) to very confident
(n=14) although most were unfamiliar with this organisation. None of the decision makers were unconfident with the
IPCC organisation, see Figure 2 below.
4
25
Not confident at all
Low level of confidence
Indifferent
Confident
Very confident
20
15
10
5
0
Total (n=40)
Decision makers
(n=10)
Communication
experts (n=9)
Academics (n=21)
Figure 2 Confidence in the IPCC by group
State of climate science
When asked to pick a statement that represented their view of the current state of climate science, most believed it was
established but incomplete while some believed it was well established, see Figure 3 below. None thought it was
speculative but five (one decision maker and four academics) believed there were competing explanations. In
conclusion, this study group had a high opinion about the current state of climate science.
30
Established but incomplete
Well established
25
Speculative
Competing explanations
20
15
10
5
0
Total (n=40)
Decision makers (n=10) Communication experts
(n=9)
Academics (n=21)
Figure 3 State of climate science by group
5