The Current Situation of Storm Surge Damage Due to Rising CO2 Levels Along the Pacific Coast of Japan - July 2023

The Current Situation of Storm Surge Damage Due to Rising CO2 Levels Along the Pacific Coast of Japan - July 2023

As of 2023, storm surge damage along the Pacific coast of Japan is rapidly worsening due to rising sea levels caused by increasing CO2 concentrations. Urban functions in major metropolitan areas such as Tokyo Bay, Osaka Bay, and Nagoya Port are particularly at risk. Over the past 30 years, sea levels have risen by approximately 12 centimeters, significantly increasing the risk of storm surges. According to a report by the Ministry of the Environment, if sea levels rise by an additional 10 to 20 centimeters, the flooded area along Tokyo Bay could expand by about 1.5 times, affecting wide areas such as Chuo Ward, Minato Ward, Koto Ward, and Shinagawa Ward in Tokyo.

### Storm Surge Risk in Tokyo Bay
In Tokyo Bay, critical infrastructure such as the Oi Thermal Power Station and oil storage facilities in Kawasaki City are concentrated along the coastline. If these facilities were flooded by storm surges, there is a risk that energy supplies would be temporarily halted. Estimates in 2022 indicate that a 1-meter rise in sea levels could affect approximately 120,000 people along Tokyo Bay, with economic losses in Chuo, Koto, and Minato wards reaching up to 3 trillion yen. Strengthening the Metropolitan Area Outer Underground Discharge Channel and increasing the number of drainage pumps to cope with storm surges have become urgent priorities.

### Storm Surge Countermeasures in Osaka Bay
Similarly, in Osaka Bay, Kansai Electric Power Sakai Refinery and industrial areas around Nanko are at risk of flooding from storm surges. Osaka Prefecture storm Surge Countermeasures Project is advancing efforts to raise levees and install about 20 drainage pumps. After the storm surge damage caused by Typhoon No. 21 in 2022, which severely affected the Minato, Nishinari, and Suminoe wards of Osaka, the reinforcement of coastal levees has been accelerated. Osaka City estimates that if sea levels rise by 30 centimeters by 2040, approximately 40 square kilometers of Osaka Bay's coastline will be flooded, resulting in economic losses of about 2 trillion yen.

### Damage Forecasts for Nagoya Port and Mikawa Bay
At Nagoya Port and Mikawa Bay, the risk of flooding from storm surges is also increasing. The concentration of Toyota Motor Corporation factories around Mikawa Bay is particularly concerning, as the surrounding industrial areas face the risk of inundation. According to a survey by Nagoya City in 2023, a 50-centimeter rise in sea levels could lead to widespread flooding across Toyoda City, Kariya City, and Anjo City in Aichi Prefecture. This flooding could impact many production sites, including those of Toyota. While Toyota is taking steps to construct levees and elevate factory equipment, further disaster prevention measures are needed.

### Specific Countermeasures for Storm Surges
1. **Reinforcing Levees**: In Tokyo Bay, Osaka Bay, and Nagoya Port, levee reinforcements and height increases are being carried out to prevent flooding caused by storm surges. Construction company Kajima Corporation is working on a project in Tokyo Bay, which aims to raise existing levees by up to 2 meters by 2025, reducing flood risks for wide areas including Chuo Ward, Shinagawa Ward, and Kawasaki City.

2. **Improving Drainage Systems**: To quickly discharge seawater overflow during storm surges, Tokyo and Osaka are increasing the number of drainage pumps. Particularly in Koto Ward and Minato Ward, Tokyo has strengthened the use of the Metropolitan Area Outer Underground Discharge Channel, which drains stormwater and seawater. In 2022, the drainage capacity was increased by 1.5 times.

3. **Corporate Disaster Preparedness**: Companies such as Toyota Motor Corporation, Kansai Electric Power, and Tokyo Electric Power Company (TEPCO) are strengthening their storm surge defenses. Toyota is constructing levees around factories along Mikawa Bay, while Kansai Electric Power is enhancing flood protection at its facilities in Sakai and Nanko.

4. **Climate Change Mitigation**: Mitsubishi Heavy Industries and Kawasaki Heavy Industries are working on the commercialization of carbon capture and storage (CCS) technology to reduce CO2 emissions and mitigate the impact of sea level rise. These initiatives aim to curb CO2 emissions into the atmosphere, helping to alleviate the rising sea level crisis.

### Economic Impact and Future Outlook
Economically, approximately 22 trillion yen is expected to be invested in storm surge countermeasures across Tokyo Bay, Osaka Bay, and Nagoya Port by 2025. These investments are expected to mitigate storm surge risks in areas such as Chuo Ward, Minato Ward, Shinagawa Ward, Osaka City Minato and Sakai Wards, and Toyoda City. However, as long as global warming continues, the risk of storm surges will continue to increase, necessitating ongoing efforts and technological development.