"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. In a second
phase of this study, we invited authors to rate their own papers. Compared to abstract ratings, a smaller percentage of
self-rated papers expressed no position on AGW (35.5%). Among self-rated papers expressing a position on AGW,
97.2% endorsed the consensus. For both abstract ratings and authors' self-ratings, the percentage of endorsements
among papers expressing a position on AGW marginally increased over time. Our analysis indicates that
the number of papers rejecting the consensus on AGW is a vanishingly small proportion of the published research."

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