Environmental policies frequently assume that people only act to help the environment if such behavior is in their self-interest. A growing amount of literature, however, shows that people also derive positive emotional benefits or “warm-glow from acting green. Yet, it remains unclear to what extent this motivation is derived from classical accounts of altruistic concern. In the current study, we leveraged a prospective design of a unique sample (N1= 341, N2 = 251) of customers who subscribe to a local sustainable food store. We measured altruistic and green warm-glow at T1 and predicted to what extent such prospective warm-glow predicted a range of self-reported conservation behaviors four weeks later (T2). Results suggest that the anticipated warm-glow from helping other people did not significantly predict green intentions nor green behavior despite being highly correlated with green warm-glow. In fact, only green warm-glow significantly predicted conservation behavior over time. These findings are important because they elucidate a basic differential motivation between helping other people versus protecting the planet. This differentiation is critical to the design of effective conservation interventions.