If you have the temerity to challenge calls for the government to take aggressive action to reduce carbon dioxide emissions, you will probably have someone call you a “climate science denier.” You will further be lectured that “97% of climate scientists agree” on this consensus.
What’s the source of this bogus stat? Cook et al. (2013) is a paper which claims to do the following:
We analyze the evolution of the scientific consensus on anthropogenic global warming (AGW) in the peer-reviewed scientific literature, examining 11,944 climate abstracts from 1991–2011 matching the topics ‘global climate change’ or ‘global warming’. We find that 66.4% of abstracts expressed no position on AGW, 32.6% endorsed AGW, 0.7% rejected AGW and 0.3% were uncertain about the cause of global warming. Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming…Our analysis indicates that the number of papers rejecting the consensus on AGW is a vanishingly small proportion of the published research. [Bold added.]
To repeat, there’s a bait-and-switch occurring here. As Friedman spells out in a very straightforward way, all you need to do is actually look at Cook et al.’s own tables in their paper to see that others (including Cook himself in a subsequent paper!) are misrepresenting their findings. Only 1.6% of the surveyed abstracts clearly say that humans are the main cause of global warming. The 97.1% figure includes papers that merely claim that some amount of warming can be attributed to human activities.
Many of the prominent scientists associated with the “denier” label–such as Richard Lindzen, Roy Spencer, Pat Michaels, and Chip Knappenberger (whom I feature here a lot)–would fit into this “consensus.” You could quite consistently hold the following beliefs:
(A) Human emissions of CO2 and other greenhouse gases have made the earth warmer than it otherwise would be. (Thus this person would be in the “97.1% consensus.”)
(B) Human activity has had a relatively minor role in the changing temperature/climate since 1750; other factors are far more significant.
(C) Climate change is not a problem worth worrying about. Malnutrition, war, and sanitary drinking water are far more urgent issues for the globe.
(D) Even if climate change poses a potentially serious threat to humans in a few decades, having governments enact certain tax policies today is not at all a suitable solution to this genuine problem.
To repeat, there is nothing contradictory about the above beliefs, and yet anyone holding (B) through (D) would be denounced as denying the “consensus.”