is based on a popular vote.
Verheggen et al. (2014) and Strengers,
Verheggen, and Vringer (2015)
reported the results of a 2012 survey
of contributors to IPCC reports,
authors of articles in scientific literature,
and signers of petitions on global warming.
7,555 authors were contacted,
and 1,868 questionnaires were
returned.
The sample was heavily biased
toward contributors to IPCC reports,
and academics most likely to publish.
The authors admit that:
“Signatories of public statements
disapproving of mainstream
climate science ... amount to
less than 5% of the total number
of respondents.”
That means
95% of respondents
had pro-consensus
climate change views.
So, did all 95% agree
with the UN's IPCC?
No, not even close to 95%
-- the surprise was that
fewer than 43% of respondents
agreed with IPCC’s claims about
man made global warming !
There is no 97% consensus,
and there never was !
The authors asked specifically
about agreement or disagreement
with IPCC’s claim in its
Fifth Assessment Report (AR5)
that it is “virtually certain”
or “extremely likely”
that human activities
are responsible
for more than half
of the observed increase
in global average temperatures
in the past 50 years.
When asked:
“What fraction of global warming
since the mid 20th century
can be attributed to human induced
increases in atmospheric greenhouse gas
concentrations?”
Only 64% chose fractions of 51% or more,
indicating agreement with IPCC AR5.
(Strengers, Verheggen, and Vringer, 2015,
Figure 1a.1)
When those who chose fractions
of 51% or more were asked,
“What confidence level
would you ascribe to your estimate
that the anthropogenic (man made)
greenhouse gas warming
is more than 50%?”
Only 65% said
it was “virtually certain”
or “extremely likely,”
which is the language used by IPCC
to characterize its "confidence level."
(Ibid., Figure 1b).
Summary:
64% of the authors
in this survey
agreed with the IPCC
on the "over 50%"
impact of human emissions
on the climate,
and 65% of those who agreed
were as confident as the IPCC
was in that finding.
65% of the 64% is 41.6%.
That means only 41.6%
of the survey’s respondents
agree with IPCC claims.
Some survey responses
were difficult to interpret.
If it is assumed that all of the
difficult to interpret responses
agreed with the IPCC,
then 42.7%
(797 of 1,868)
of respondents
were highly confident
that more than 50%
of the warming
was human-caused.
Verheggen et al.
were embarrassed
by their findings,
and hid them in tables
in a report published
a year after
their original publication
of survey results.
A blogger called attention
to the real data.
(Fabius Maximus, 2015).
Sources:
Strengers, B., Verheggen, B., and Vringer, K. 2015.
Climate science survey questions and responses (April 10).
PBL Netherlands Environmental Assessment Agency.
Verheggen, B., Strengers, B., Cook, J. van Dorland,
R., Vringer, K., Peters, J. Visser, H., and Meyer, L. 2014.
Scientists’ views about attribution of global warming.
Environmental Science & Technology 48:
16. 8963–8971, DOI: 10.1021/es501998e