Environ. Res. Lett. 12 (2017) 084019 3.2.2. Non-peer-reviewed publications Non-peer-reviewed documents offer a mix of positions (figures 1(b) and 2(b)). Among the 47% (22/47) that take a position, 45% (10/22) ‘Acknowledge’, 41% (9/22) ‘Doubt’, and 14% (3/22) ‘Acknowledge and Doubt’. As with Endorsement Levels, several of the expressions of doubt in non-peer-reviewed documents reflect the industry-targeted communications included in this category (see sections S2, S3, and S6, supplementary information). 3.2.3. Internal documents Internal documents typically acknowledge the potential for serious impacts but also highlight uncertainties. Of the 53% (17/32) of documents with a position, 35% (6/17) ‘Acknowledge’ and 47% (8/17) ‘Acknowledge and Doubt’ (figure 2(b)). A characteristic acknowledgement is found in a 1980 Exxon memo, which says, ‘There are some particularly dramatic questions that might cause serious global problems. For example, if the Antarctic ice sheet[,] which is anchored on land, should melt, then this could cause a rise in the sea level on the order of 5 meters. Such a rise would cause flooding in much of the US East Coast including the state of Florida and Washington D.C.’ [98] (see also [83]). An example of doubt is a 1981 report stating ‘that it has not yet been proven that the increases in atmospheric CO2 constitute a serious problem that requires immediate action’ [111] (table 4). 3.2.4. Advertorials In contrast, ExxonMobil advertorials overwhelmingly take the position of doubt (e.g. peer-reviewed publications versus advertorials: p ¼ 0:045, FET). Of the 58% (21/36) of advertorials that take a position, 62% (13/21) express ‘Doubt’ (figure 2(b)). Most of the remainder express a mixed position (5/21 = 24%). Often, they express the opinion that concern over climate impacts is alarmist, such as a 1995 advertorial entitled ‘The sky is not falling,’ which asserted, ‘The environment recovers well from both natural and man-made disasters’ [112] (table 4). 3.3. Solvable Levels (SLs)—AGW as solvable Positions on AGW as solvable vary significantly across document categories (p ¼ 3:4 # 10!12 , FET). Figure 2(c) shows that only 3% (2/72) of peer-reviewed papers express doubt that AGW is solvable. Internal and non-peer reviewed materials also express relatively low levels of doubt: 9% (3/32) and 19% (9/47), respectively. In contrast, 64% (23/36) of advertorials do so (e.g. peer-reviewed publications versus advertorials: p ¼ 2:8 # 10!12 , FET). The ‘Doubt’ arguments are relatively consistent across document categories (table 5), typically suggesting that climate mitigation strategies will either fail or create bigger problems. The arguments point to one or more of: limitations of renewable energy and 11 other technologies such as carbon capture and storage; an (alleged) dichotomy between climate mitigation and poverty reduction; and potential adverse economic impacts of mitigation. However, there is a discernible difference in the prominence and emphasis that these concerns are given in advertorials compared to other documents. In particular, in advertorials, the remedies for AGW are presented as a grave threat, whereas climate change itself is not. For example, advertorials claimed that the Kyoto Protocol to the United Nations Framework Convention on Climate Change would be ‘financially crippling’ and ‘economywrecking’ [122, 123]. It, or strategies like it, would lead to ‘severe dislocations throughout the world economy,’ an ‘unprecedented transfer of wealth,’ and be a ‘blow to US prosperity’ [124–126]. One 1997 advertorial warns: ‘Flexibility will be constrained. Carpooling in; sport utility vehicles out. High fuel and electric bills. Factory closures. Job displacement. And could businesses and consumers cut their energy consumption by 30 percent without some form of tax or carbon rationing? Probably not’ [92]. A 2000 advertorial contrasts the unpredictability of AGW against the asserted ‘certainty that climate change policies, unless properly formulated, will restrict life itself ’ [121] (table 5). 3.4. Stranded fossil fuel assets The number of times the concept of stranded fossil fuel assets is mentioned varies significantly across document categories (p ¼ 0:0042, FET). In total, 24 of the analyzed documents allude to the concept of stranded fossil fuel assets: seven peer-reviewed publications, ten non-peer-reviewed publications, and seven internal documents. No advertorials address the issue. Stranded assets are discussed in two ways (see table 6 and section S5, supplementary information): (i) Implicit, qualitative connections between fossil fuel reserves/resources/use and either greenhouse gas limits or possible climate mitigation policies; and (ii) explicit quantifications of ‘cumulative emissions’ and/or ‘carbon budgets’ consistent with greenhouse gas stabilization. 3.4.1. Qualitative connections These discussions imply limitations on fossil fuel use because of greenhouse gas limits or climate mitigation. ‘Mitigation of the “greenhouse effect”,’ says the 1982 internal Exxon primer, ‘would require major reductions in fossil fuel combustion’ [83]. Likewise, an internal 1979 Exxon study found that ‘should it be deemed necessary to maintain atmospheric CO2 levels to prevent significant climatic changes . . . coal and possibly other fossil fuel resources could not be utilized to an appreciable extent’ [82]. 3.4.2. Quantitative carbon budgets These discussions introduce, with varying degrees of detail, ideas of ‘cumulative fossil fuel use,’ ‘cumulative