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Sunday, June 3, 2018

Proof there is no 97% "consensus" using a rare, somewhat honest survey

Not that real science 
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