In climate change communications, do attitudes towards humans influence pro-environmental action? If so, does it depend on endorsement of self-transcendence values? Two experiments examined these questions by assessing the effects of activating positive (vs. negative) humanity esteem on environmental motives, personal moral norms, and behavioural intentions to protect the environment. The experiments tested whether the effects of humanity esteem depend on individuals' self-transcendence values. Results indicated that among people who endorse self-transcendence values less strongly, those in the positive (vs. negative) humanity-esteem condition had lower ecocentrism (Experiment 1) and weaker personal norms, which led to weaker behavioural intentions to protect the environment (Experiment 2). In contrast, across the two humanity-esteem conditions, people who more strongly endorsed self-transcendence values showed stronger ecocentrism, personal moral norms, and behavioural intentions to protect the environment. Thus, for people with weaker self-transcendence values, portrayals of humanity play a role in people's engagement with environmental causes. textcopyright 2014 John Wiley Sons, Ltd.