Photo/Illutration A ski resort in Nagano Prefecture is closed on Jan. 20 due to the record warm winter weather. (Asahi Shimbun file photo)

Amid the COVID-19 pandemic, I almost forgot how abnormally warm Japan's weather was during this past winter.

In Africa, heavy rains triggered a massive outbreak of desert locusts, while a period of hot, dry weather led to a spate of bushfires in Australia.

These extreme phenomena, which occurred one after another, have been linked to what climate scientists refer to as the Indian Ocean Dipole.

"It's also called the Indian Nino," noted dynamic meteorologist Takeshi Doi, 38, a researcher at the Japan Agency for Marine-Earth Science and Technology (JAMSTEC).

Simply put, the Indian Ocean Dipole refers to larger-than-usual differences in sea surface temperatures in opposite parts of the Indian Ocean.

The differences in 2019 were of the greatest magnitude on record, and they continued into 2020, causing heavy floods in nations along the west coast of the Indian Ocean and severe drought in those along the east coast.

And these phenomena pushed the subtropical westerlies to the north, which brought a record warm winter to Japan.

"Ultimately, climate is the result of collaboration between the sky and the sea," Doi observed.

The Indian Ocean Dipole is said to be a phenomenon that occurs every few years. By keeping track of the Indian Ocean's water temperatures, meteorologists are striving to improve the accuracy of their forecasts by trial and error.

Japan will have another wet and brutally hot summer this year because of the Indian Ocean Dipole, according to Doi.

I was quite surprised to learn that the locust infestation in faraway Africa and Japan's unseasonably mild winter shared the same cause.

If a disaster can be foretold months in advance, it should be easier to take preventive action around the world. In South Africa, for instance, I understand that predicting the timing of a malaria outbreak makes it possible to spray an insecticide effectively.

The dreaded season of lethal downpours and floods is here again. Now that the COVID-19 crisis has taught us of the uselessness of the "my country first" policy, I just hope global efforts will be made to prepare for extreme weather episodes.

--The Asahi Shimbun, June 18

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Vox Populi, Vox Dei is a popular daily column that takes up a wide range of topics, including culture, arts and social trends and developments. Written by veteran Asahi Shimbun writers, the column provides useful perspectives on and insights into contemporary Japan and its culture.

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