Negativity captures attention and motivates people to read and share news, but may also harm mental health, bias memory, and discourage sustained action to address long-term problems like climate change. We investigated how the affective framing of environmental news influenced immediate engagement and delayed memory. In two experiments, we adapted news headlines to feature different aspects of each story, emphasizing Crisis or Opportunity. Results revealed a key trade-off. Crisis framing maximized immediate engagement—motivating reading, sharing, and donating—but impaired memory for images associated with the headlines. Opportunity framing still modestly increased engagement, while also enhancing memory for detailed news text. Importantly, we attribute the effects of Crisis and Opportunity framing to multiple mechanisms. Crisis framing enhanced immediate engagement and impaired memory via a combination of negative affect and urgency, whereas Opportunity framing enhanced memory via a combination of positive affect and agency. Lastly, we conducted a large-scale analysis of >25,000 news headlines posted on social media, providing converging evidence that affect and urgency jointly shape real-world news engagement. Overall, we demonstrate that framing strategies modulate reading, sharing, donations, and memory in laboratory and real-world settings.