Environ. Res. Lett. 12 (2017) 084019 These results are explained by the early publication period of internal documents: all but two were published before the 1990 IPCC report, and are therefore subject to our filters for reasonable doubt. These results also reflect the predominant nature of the internal documents: they acknowledge the likelihood of AGW based on internal and external research, while also highlighting uncertainties. In 1979, for instance (table 3), an internal Exxon study concluded that: The most widely held theory is that: $ The increase [in atmospheric CO2] is due to fossil fuel combustion $ Increasing CO2 concentration will cause a warming of the earth’s surface $ The present trend of fossil fuel consumption will cause dramatic environmental effects before the year 2050. However, the memo notes: ‘It must be realized that there is great uncertainty in the existing climatic models because of a poor understanding of the atmospheric/terrestrial/oceanic CO2 balance’ [82]. Likewise, an internal briefing on the ‘CO2 “Greenhouse” Effect’ from 1982 states: ‘There is currently no unambiguous scientific evidence that the earth is warming. If the earth is on a warming trend, we’re not likely to detect it before 1995’ (see table 3). Yet, the authors say, ‘Our best estimate is that doubling of the current concentration could increase average global temperature by about 1.3 °C to 3.1 °C’ [83]. Several internal documents make this distinction, acknowledging that increased CO2 would likely cause warming, while expressing (reasonable) doubt that warming was already underway and large enough to be detected. This cautious consensus is also evident in charts in internal ExxonMobil presentations and reports. (Due to copyright restrictions prohibiting the reproduction of figures owned by ExxonMobil, we instead provide hyperlinks to third-party websites at which relevant figures can be viewed.) For example, in a 1978 presentation to the Exxon Corporation Management Committee, Exxon scientist James Black showed a graph (see https://perma.cc/PJ4N-T8SC) of projected warming ‘model[ed] with the assumption that the carbon dioxide levels will double by 2050 A.D.’ [95]. Another case is the 1982 Exxon primer already mentioned, which includes a graph (see https://perma. cc/PH4X-ZJBA) showing ‘an estimate of the average global temperature increase’ under the ‘Exxon 21st Century Study-High Growth scenario’ [83]. A third example is a table (see https://perma.cc/9DGQ4TBW) presented by Exxon scientist Henry Shaw at a 1984 Exxon/Esso environmental conference, which showed that Exxon’s expected ‘average temper8 ature rise’ of 1.3 °C–3.1 °C was comparable to projections by leading research institutions (1.5 °C– 4.5 °C) [96]. This shows that ExxonMobil scientists and managers were well informed of the state of the science at the time. But they also tended to focus on the prevailing uncertainties: Black stressed the alleged shortcomings of extant climate models before showing his results; Shaw emphasized the variable and ‘unpredictable’ character of some values. We conclude that ExxonMobil’s recent defense accurately characterizes the situation with respect to its peer-reviewed, non-peer-reviewed, and internal documents: ‘Our researchers recognized the developing nature of climate science at the time . . . [and] mirrored global understanding’ [14]. On several occasions during the early 1980s, the company’s peer-reviewed and internal documents went as far as to refute ‘calculations on a more limited scale by a number of climatologists’ that projected much less global warming than the rest of the scientific community, including ExxonMobil [97–99]. ‘In summary,’ said a 1982 memo, ‘the results of our research are in accord with the scientific consensus on the effect of increased atmospheric CO2 on climate . . . and are subject to the same uncertainties’ [99]. As a scientific consensus emerged in the early 1990s that AGW was underway, a 1995 ‘Primer on Climate Change Science’ co-authored by Mobil as part of the Global Climate Coalition explicitly rejected contrarian claims that were beginning to circulate: ‘Contrarian theories . . . do not offer convincing arguments against the conventional model of greenhouse gas emission-induced climate change’ [100]. 3.1.4. Advertorials The predominant stance taken in ExxonMobil’s advertorials is ‘Doubt’. In essence, these public statements reflect only the ‘Doubt’ side of ExxonMobil’s mixed internal dialogue. Figures 1(a) and 2(a) show that of the 72% (26/36) of climate change advertorials that take a position, 81% (21/26) take the position of ‘Doubt’, with the remainder split between ‘Acknowledge’ (3/26 = 11.5%) and ‘Acknowledge and Doubt’ (2/26 = 7.5%). A characteristic example is a 1997 Mobil advertorial (table 3), which stated: ‘Let’s face it: The science of climate change is too uncertain to mandate a plan of action that could plunge economies into turmoil . . . Scientists cannot predict with certainty if temperatures will increase, by how much and where changes will occur. We still don’t know what role man-made greenhouse gases might play in warming the planet’ [92]. Another, also from 1997, referred to a ‘high degree of uncertainty,’ ‘debate,’ and a ‘knowledge gap,’ and the need for further ‘fact-finding’ and ‘additional knowledge’ before UN negotiators in Kyoto could make decisions [94]. The advertorial stressed the goal ‘of achieving a consensus view,’ two years after the IPCC had presented one.