When people estimate the summative carbon footprint of a sequence of events, how are the individual events integrated? In three experiments, we found that summative carbon footprint judgments of item sequences are disproportionately influenced by items at the end of the sequence in comparison with those at the beginning—a recency effect. When, for example, sequences ended with a low carbon footprint item, they were assigned a lower carbon footprint than corresponding sequences with an identical content but different item order. The results also revealed that a green peak (presenting many low carbon footprint items at once) had a relatively large effect on estimates when the peak was contextually distinct from other items in terms of its valence. The results are consistent with an account within which distinctiveness of representations within short‐term memory differentially influences decision‐making and suggest that memory processes bias the perceived environmental footprint of temporally separated instances.