Abstract Would you follow advice about personal energy conservation from a climate specialist with a large carbon footprint? Many climate researchers report anecdotes in which their sincerity was challenged based on their alleged failure to reduce carbon emissions. Here, we report the results of two large online surveys that measure the perceived credibility of a climate researcher who provides advice on how to reduce energy use (by flying less, conserving home energy, and taking public transportation), as a function of that researcher’s personal carbon footprint description. Across the two studies, we randomly assigned partici- pants to one of 18 vignettes about a climate scientist. We show that alleged large carbon footprints can greatly reduce the researcher’s credibility compared to low footprints. We also show that these differences in perceived credibility strongly affect participants’ reported intentions to change personal energy consumption. These effects are large, both for participants who believe climate change is important and for those who do not. Participants’ politics do affect their attitudes toward researchers, and have an extra effect on reported intentions to use public transportation (but not on intentions to fly less or conserve home energy). Credibility effects are similar for male and female climate scientists.