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.

The consensus that humans are causing recent global warming is shared by 90%-100% of publishing climate scientists according to six independent studies by co-authors of this paper. Those results are consistent with the 97% consensus reported by Cook et al (Environ. Res. Lett. 8 024024) based on 11 944 abstracts of research papers, of which 4014 took a position on the cause of recent global warming. A survey of authors of those papers (N=2412 papers) also supported a 97% consensus. Tol (2016 Environ. Res. Lett. 11 048001) comes to a different conclusion using results from surveys of nonexperts such as economic geologists and a self-selected group of those who reject the consensus. We demonstrate that this outcome is not unexpected because the level of consensus correlates with expertise in climate science. At one point, Tol also reduces the apparent consensus by assuming that abstracts that do not explicitly state the cause of global warming ('no position') represent nonendorsement, an approach that if applied elsewhere would reject consensus on well-established theories such as plate tectonics. We examine the available studies and conclude that the finding of 97% consensus in published climate research is robust and consistent with other surveys of climate scientists and peer-reviewed studies.

Synopsis The late Carboniferous (Stephanian) quartz-dolerite dyke swarm of northern Britain extends eastwards from the Outer Hebrides on an arcuate trend for up to 200 km from the eastern UK coast, as far as the western margin of the Central Graben. The average trend of the swarm changes by about 45° between its western and eastern extremities. Individual dykes, which are generally up to 30 m wide onshore, attain widths of well over 1 km offshore. Magmatically and spatially, the swarm is closely related to the coeval Oslo Graben volcanic rocks and dykes of southern Norway, which lie on the extrapolation of the arcuate trend. The dyke trends point to a focus of relative tensile stress centred on the West Shetland Shelf region. Finite element modelling of the NW European area corroborates the stress-focusing hypothesis, which we interpret in the context of the major period of intra-continental rifting along the line of the proto North Atlantic (the Rockall Trough, Faeroe–Shetland Trough and eastern Norwegian Sea) at about 300 Ma. The regional distribution of Archaean and Caledonian lithosphere within Pangaea may account for the fact that both the dyke swarm and the Oslo Graben were located in northern Britain and southern Norway, rather than in the Faeroe–Shetland region.

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Cook et al. reported a 97% scientific consensus on anthropogenic global warming (AGW), based on a study of 11,944 abstracts in peer-reviewed science journals. Powell claims that the Cook et al. methodology was flawed and that the true consensus is virtually unanimous at 99.99%. Powell’s method underestimates the level of disagreement because it relies on finding explicit rejection statements as well as the assumption that abstracts without a stated position endorse the consensus. Cook et al.’s survey of the papers’ authors revealed that papers may express disagreement with AGW despite the absence of a rejection statement in the abstract. Surveys reveal a large gap between the public perception of the degree of scientific consensus on AGW and reality. We argue that it is the size of this gap, rather than the small difference between 97% and 99.99%, that matters in communicating the true state of scientific opinion to the public.