A more recent example was the week or more in 2011. DDG's top result
https://weathermodificationhistory.com › september-11-2001-airline-groundings-contrails-affect-daily-temperature-range
September 11, 2001 Airline Groundings: Contrails Affect Daily ...
During the 11-14 September 2001 grounding period natural clouds and contrails were noticeably absent on high-resolution satellite imagery across the regions that typically receive abundant contrail coverage. A previous analysis of temperature data for the grounding period reported an anomalous increase in the U.S.-averaged, 3-day DTR value.
Is the 12,000-year cycle more likely to be asteroids or vulcanism?