Agradecimentos: We would like to express our gratitude to the two anonymous reviewers who contributed with great inputs to improve the earlier versions of this manuscript. We are very grateful to all the professors, university staff, and students who have dedicated a lot of efforts to keep the Meteorological Observatory Professor Jesus Marden dos Santos from the "Luiz de Queiroz" College of Agriculture (ESALQ) of University of São Paulo (USP), data source of this study, in operation for more than 100 years. Indefatigable, Paulo Cesar Sentelhas was one of those distinguished professors who dedicated their entire academic life to keep the centennial weather station running. Sadly, Professor Paulo Cesar Sentelhas passed away on 21 September 2021, due to complications from COVID-19. He first idealized this scientific contribution. Professor Sentelhas will be missed by many in Brazil and around the world due to his talent as teacher, scientist, and extensionist, in particular in the agrometeorology community. We, Clayton Alcarde Alvares and Henrique Boriolo Dias, dedicate this contribution to Paulo’s memory Ver menos

Abstract: Many regions around the world are facing climate changes, with substantial increase in air temperature over the past decades, which is mainly related to continental and global warming forced by the higher greenhouse gas (GHG) emissions. The objectives of this study were to use the Köppen climate classification to detect local climate change based on a historical series of 100 years and to assess if such change is related to those that are occurring in other spatial scales as a likely consequence of increasing GHG. This paper brings a content full of innovative results. The study area presented an average annual air temperature increase by 0.9 °C between 1917 and 2016, rising from 21.4 °C for the first climatological normal (1917–1946) to 22.3 °C for the last one (1987–2016). Furthermore, in the summer months, the temperature rose from 24.5 to 25.3 °C, and in the winter months, such increase was from 17.1 (1917–1946) to 18.3 °C (1987–2016). Our findings showed the subtropical conditions (Cfa in Köppen’s classification) in the study area persisted from the beginning of the analysis (1917–1946) until the climatological normal of 1979–2008, with a clear tendency of tropicalization after that with a change in the climate type of Piracicaba from subtropical to tropical, which can now be classified as tropical with dry winter (Aw climate type). The local average air temperature showed concordances with the long-term air temperature anomalies from regional, continental, and global scales, indicating that all of them may be linked with increasing GHG emissions, since well-defined long-term linear relationships (r2 = 0.99) were observed between continental and global average air temperature anomalies and atmospheric CO2 concentration observed at the NOAA Lab in Mauna Loa in the last 59 years. While the local and regional forcing effects remain to be fully unraveled, our study provided a valid and strong scientific sound evidence that climate change occurred in Piracicaba, southeastern Brazil, in the last 100 years Ver menos