Although smaller in scale, the Sea of Japan has the same elements as the world's oceans such as the Pacific Ocean. In 2017, it gained attention as studies revealed alarming changes occurring in the Sea of Japan. Deep circulation, considered to be the lifeline of the sea, had weakened by 30%. In addition, the amount of oxygen saturation in the deep waters had decreased. The cycle of deep circulation in the Sea of Japan is 20 times faster than that of the world's great oceans. Experts point out that by observing the changes occurring in the Sea of Japan, we can watch the world's phenomenon in fast motion. This episode will delve into the latest research on the Sea of Japan to predict the future of our world.