'A miscalibrated thermometer is just as likely to read too high as it is to read too low. Human error has no systematic bias. The only systematic error is UHI, which should cause corrections to be increasingly negative. What are odds of 840 months in a row having temps which were read too low by thousands of observers? ...there is a 0% chance USHCN adjustments are correct, & 100% probability they are politically motivated, or at best conformation bias'