Increasingly, more scientists sound the alarm about climate change, sparking debates over the effects of new science communication strategies on scientific credibility. We investigate what happens when climate scientists deviate from science communication that is principally factual and neutral. In an experiment (US sample, 882), we investigated if affective expressions and personal stories impact scientists' credibility and public climate engagement. The results suggest that when climate scientists incorporate affect or personal anecdotes into their messaging, it does not significantly diminish their credibility. Nevertheless, message consistency is essential; only by aligning the narrative with expressed affect can scientific credibility and climate engagement be increased.