The term Scientific consensus is, by definition, an evidence-based consensus. It does not necessarily refer to 100% unanimity among all human beings, nor even among 100% of people trained in science. Rather, it refers to a consilience of scientific evidence upon which an overwhelming majority of scientists (whose areas of expertise are most pertinent) concede to what the evidence is showing.
It does not mean that every single nuance of every tangentially related question is known with absolute certainty. It just means that no credible reason remains for denying the implications of the evidence with respect to the bigger picture.
Many areas for which there is strong scientific consensus continue to be controversial topics among laypeople (i.e. GMO safety, vaccine efficacy and safety, evolution, Anthropogenic Global Warming, water fluoridation etc), but this is due almost exclusively to a combination of a lack of sufficient competence at evaluating the veracity and meaning of information related to a particular scientific field, and/or motivated reasoning rooted in staunch ideological opposition to something about the particular field of study and its findings.