Organ tuning
From Chris Baraniuk, a climate story from an unlikely source:
"[Yangang] Xing, Knight and their colleague Bruno Bingley published a paper in the journal Buildings & Cities, which describes preliminary data gleaned from 18 organ tuning books. These records were sourced from churches in London, Nottinghamshire and Derbyshire and date back to 1966. They indicate a rise in average temperatures inside churches since then, during winter and summer periods."
Read it all: Church organ tuning records mirror our warming climate