Climate Change: 97% scientific consensus? Try 99.94% instead
There is an increasing trend in journalism to cite a figure of 97% for the consensus among the scientific community in regards to human-caused climate change. We don't want to be too critical of organisations that highlight the immensely high level of agreement regarding climate change, however it is also important to maintain accuracy.
Where does 97% come from?
- In 2013 a study by Cook et al. was published entitled "Quantifying the consensus on anthropogenic global warming in the scientific literature".
- This study analysed 11,944 peer reviewed papers published between 1991-2011 in climate science literature.
- Of these papers, 4013 expressed a position on human-caused climate change. Of these, 3894 (or 97%) supported the position that humans are causing climate change.
- The authors also state an increasing trend of acceptance over time of human-caused climate change.
- In 2017 James Powell published a meta-analysis of peer reviewed climate change literature from 1991-2015, inclusive of 54,195 articles.
- Using rejection as the criterion for consensus he found 99.94% consensus about human-caused climate change.
- This is consistent with Cook et al. who described increasing acceptance over time.
- Perhaps this figure of 99.94% is also too low. For Powell's studies examining peer review articles published during 2013 and 2014 there was 99.99% consensus.