I’m guessing this is something to do with the fact that people are more averse to losing something than they are happy about getting it.
I came across that fact in a marketing guide, of all places. People are more likely to buy products when they’re framed in terms of “Hesitate and you’ll miss this great offer” instead of “Act now and get all this cool stuff extra”.
Psychological tactics aside, yes, it would be nice to have more hopeful messages too. Perhaps stories exploring new societies or lifestyles that have learned to live more sustainably? One example that comes to my mind immediately is the topic in the below article, but in a more storylike form:
If we can start thinking differently, even for the little while we’re reading a book, it could slowly help change the narrative. Maybe we can inspire people to tackle climate change, instead of scaring them into doing it.