Companies worried about protecting the image of their brands online are needlessly turning down opportunities to advertise alongside content about climate change.

Firms have long kept lists of trigger words that can stop their digital ads from appearing next to content they consider to be difficult or controversial, such as terrorism or Brexit. The blunt tactic can deprive publishers of revenue for important stories, as happened in the early days of the pandemic, when brands were wary that marketing next to covid news would turn consumers off of their products.