A recent analysis by The Asahi Shimbun unveiled that unofficial data from weather authorities in Japan implies that temperatures during summers in the late 1990s and early 2000s might have been higher than previously recorded. The study discovered that 158 locations across the country experienced maximum temperatures that were between 0.1 to 1.3 degrees higher than the official records during the period of 1994 to 2002. The revelations were based on hourly temperature recordings collected at approximately 760 unstaffed observation points until 2002 by the Japan Meteorological Agency (JMA).
Surprisingly, the JMA also gathered temperature data every 10 minutes between 1994 and 2002; however, these more detailed readings were not incorporated into the official records and are considered unofficial. This additional data allowed for a closer examination of specific instances such as Ikomayama in Osaka Prefecture registering a high temperature of 35.6 degrees on August 6, 1994, which was 1.3 degrees higher than the official record. Similarly, Ezarugi in Saga Prefecture recorded a high of 37.3 degrees on August 10, 1994, also surpassing the official record by 1.3 degrees.
The discrepancies uncovered by The Asahi Shimbun's analysis have shed light on the importance of utilizing old data for research purposes, as mentioned by Masahiro Watanabe, a climate science professor at the University of Tokyo's Atmosphere and Ocean Research Institute. While these findings could provide valuable insights into historical climate patterns, Watanabe emphasizes the need to not downplay the urgency of addressing ongoing climate change concerns. He warns against misinterpreting the potentially hotter summers of the past as indicative of a lack of global warming, asserting that it is vital to remain vigilant in combating climate change despite historical temperature variations.