 As with detection, IPCC conclusions related to attribution have grown stronger over time and have come to encompass more variables and fields. In their Fifth Assessment Report, the IPCC concluded that it is “extremely likely” (i.e., probability &gt;0.95) that more than half of the increase in global mean surface temperature since 1950 was due to anthropogenic greenhouse gas emissions and other anthropogenic forcings (Bindoff et al. 2013: 869). This conclusion was informed by multiple fingerprint studies, as well as physical reasoning and expert judgment. The latter underwrite key assumptions of the attribution exercise (e.g., that no significant causes have been overlooked) and, relatedly, play a role in deciding the extent to which face-value probabilities produced in fingerprint studies should be downgraded (e.g., from “virtually certain” to “extremely likely”) in light of remaining uncertainties and recognized limitations of those studies. For various other changes, including increases in global mean sea level since the 1970s and retreat of glaciers since the 1960s, the IPCC concludes that it is at least “likely” (i.e., probability &gt;0.66) that human influence played a role (ibid.: 869–871).