Will Blows from Hagibis Raise Japan's Awareness on Global Warming? Updated in August 2020

On the night of October 12, 2019 typhoon Hagibis landed on Izu Peninsula near the Tokyo metropolitan area, causing serious damage in wide areas across the archipelago. 5 days after the landing of the typhoon, the number of dead or missing totaled 79. River embankments were broken at 90 sites in 59 rivers. There were 241 cases of landslides, and 6,500 hectares of farm fields were affected, damaging both crops (rice, soybean, tomato, eggplant, apple, pear and many others) and farming facilities. The damage for agricultural produce is estimated to be 24.9 billion yen. 25 medical institutions in 7 prefectures were flooded. 6 hospitals including one in Tokyo had to transfer patients to partnering facilities.

AC Photo: Kani Bozu

Rise in Sea Surface Temperature Intensified Hagibis
Researchers who kept stressing the need to allocate more national funds on natural disaster countermeasures feel a desperate sense of crisis. 8 years after the Great East Japan Earthquake (March 11, 2011), debate over disaster-mitigation for large natural disasters may resurface. Due to the typhoon's path and the scale of damage, some people are worried about its correlation with global warming. If Japan were a coastal country consisting of smaller islands, the damage could have been worse. 3 days after the mega-typhoon, high hopes for Japan's advanced disaster-mitigation expertise and renewable energy technologies were voiced during a symposium on global warming: Japan's environmental technologies to reduce greenhouse gases and combat global warming could highly benefit many countries.

Influential researchers across the globe who played major roles in compiling IPCC's “Special Report on the Ocean and Cryosphere in a Changing Climate” (SROCC) were invited to the October 15 symposium hosted by Sasakawa Peace Foundation. Results from the 51st IPCC session in Monaco (September 20-24) are included in the IPCC report consisting of 6 chapters. The purpose of the symposium was to have 5 of the lead authors introduce highlights of the 5 chapters they drafted. The event took place while destructive damages from the typhoon were reported daily. The speakers had also made series of remarks regarding Hagibis. *Intergovernmental Panel on Climate Change

One of lead authors of Chapter 5, Prof. Toshio Suga (Department of Geophysics, Graduate School of Science, Tohoku University) showed the latest map published by Japan Meteorological Agency (JMT). From that map, it is possible to predict sea surface temperature (SST) around Japan. SST is calculated from observation values by satellites, buoys and ships. On October 12 when Hagibis landed on Izu Peninsula, areas of the sea with surface temperature of 27 degrees Celsius spread to the south of the archipelago. JMT also publishes a daily map showing differences in observed SST in comparison to the normal value. Normal values are average values observed within 1981-2010. By comparing the two maps, we can see that 27 degrees is 1 degree higher than the normal value, the IPCC Special Report pointed out that “SST has certainly risen since 1970. Since 1993, its temperature has doubled.” A phenomenon consistent with the contents of the Special Report was occurring in seawaters just south of the Japanese archipelago─the exact path Hagibis traveled through.

Normally, as typhoons approach Japan, the SST falls and the amount of water vapor decreases, causing the typhoon to lose power. After such facts, Prof. Suga expressed his view that "SST of 27 degrees Celsius─higher by 1 degree─could have caused Hagibis to land without losing destructive power." JMT had already foreseen serious damage 3 days before the typhoon's landing, while it was still lingering around south of Japan. This resulted in an effective early warning. It was already clear that SST for the oceans south of Japan had reached 27 degrees. That was one of the strong grounds for JMT to issue a warning three days prior to the landing.

The SST map tells us that sections of the ocean that display SST that are 2-3 degrees higher than normal level, were spreading towards the southeastern side of Japan, 3 days before the typhoon landed. Prof. Suga also revealed an eerie prediction: “It is highly possible that SST directly south of Japan could regularly exceed normal temperature by 3 degrees. This means that huge typhoons can always hit Japan during future typhoon season.”

High Hopes for Japan's Technology Overseas researchers in the symposium were also evaluating Japan's technologies in flood control and renewable energy, which may greatly help in reducing greenhouse gases. One of lead authors of Chapter 4 Dr. Rongshuo Cai (Deputy Director, Third Institute of Oceanography, State Oceanic Administration of China) appreciated Japan's excellent countermeasures and early warning systems. He said that if a typhoon like Hagibis should hit developing countries, the damage could have been more drastic.

One of lead authors of Chapter 6, Dr. Raden Dwi Susanto, (Senior Research Scientist, University of Maryland) said that Japan's flood control facilities and early warning systems are effective in preventing economic loss from natural disaster and that “there are many things to learn from Japan's disaster-mitigation measures.” And “Japan should stand out as country that invests in disaster prevention and mitigation,” he added.

Keynote speaker Dr. Hans-Otto Pörtner (Co-Chair Working Group II, IPCC) also expressed high expectations for Japan, particularly the need for effective solutions to counter rise in sea level caused by global warming: “Japanese companies have technology for marine regenerative energy like ocean thermal power and tidal power generation. Japan should take leadership so that coastal and island countries can use these technologies. "

In Japan, people will maintain much interest in supporting disaster-stricken areas for some time. As global warming measures are attracting much attention among all generations now, Japan should not forget expectations from the international community as an advanced country that can provide solutions for pressing agendas. (T.K)

Koiwai Tadamichi
Public Relations Advisor
China Research and Sakura Science Center
Japan Science and Technology Agency