The spread of influential misinformation, such as conspiracy theories about the existence of a secret, large-scale atmospheric spraying program (SLAP), is contributing to the politicization of science. In an important recent study, Sheareret al (2016 Environ. Res. Lett. 11 084011) employ a novel methodology to quantify the expert consensus of popular SLAP assertions. The authors find that 99% (76/77) of surveyed experts have not encountered any evidence that would support the existence of such a program. Here we argue that this finding is important because a growing body of research has shown that the public’s perception of expert consensus on key societal issues acts an important ‘gateway’ to science acceptance. Furthermore, communicating normative agreement among experts, such as the strong scientific consensus against the existence of a SLAP, can help limit the spread of misinformation and promote more effective public decision-making about science and society. Download the article here.