The research group of the Atmosphere and Ocean Research Institute of the University of Tokyo and the Japan Agency for Marine-Earth Science and Technology have continuously elucidated the climate change around the capital Tokyo for the past 4400 years from marine sediments with high time resolution.He points out the potential impact of repeated climate change on Japanese history.
In recent years, "climate change" has become a big topic, and there are concerns about adverse effects on future human society such as global warming.On the other hand, what was the impact of climate change in the past?So far, the research group has conducted research on the coastal areas of East Asia where many civilizations prospered in order to evaluate the impact of past climate change on humankind, but this time, the past climate around Tokyo We aimed to restore fluctuations continuously and with high time resolution.
Therefore, the sedimentary columnar core was collected from the center of Tokyo Bay, and the sedimentary age was determined by dating the shell fossils.The organic matter contained in the sediments was investigated, and the surface seawater temperature fluctuations over the past 4400 years were analyzed precisely.Since the temperature on the coast changes with the seawater temperature, it is possible to analyze the climate change in Tokyo from the surface water temperature fluctuation.
As a result, nine prominent temperature peaks have been identified during the last 4400 years, mainly due to the intensity of solar activity and volcanic eruption activity.In particular, (9) "4.2ka climate event" (global drying and cooling about 4200 years ago) corresponding to the collapse / deterioration of global civilization, (XNUMX) the boundary period of the Jomon / Yayoi period, and (XNUMX) the civil war of the end of Yayoi period ( During the period of the Civil War of Wa) and (XNUMX) the rise of the samurai family at the end of the Heian period, a large amount of cooling was observed.
The timing of these cold events coincides with a turning point in Japanese history, suggesting that society has been affected by climate.In order to draw the future plan of Japan with the past as a lesson for the future, it is necessary to fully consider the countermeasures based on the correct prediction of climate change.
