Mainichi Daily News: The summers of the Bakumatsu period were hot, according to analysis of records from the period done by the Mainichi Shimbun and academic experts; and the high temperatures may be an indicator of when global warming began. “Comparing this data with present day temperatures will help us understand long-term climate change, and the progress of global warming,” says one expert. The records were kept by a Mito Domain merchant by the name of Otaka. Otaka consulted a thermometer …