13-Kyushu and Kanto Coastal Erosion and Natural Recovery Issues (1990s to 2020s) - August 1995 - Environmental Issues

13-Kyushu and Kanto Coastal Erosion and Natural Recovery Issues (1990s to 2020s) - August 1995 - Environmental Issues

1990s: Growing Concerns Over Coastal Erosion and Initial Responses

In the 1990s, rapid coastal erosion became a prominent issue in Japan. Particularly in areas like Tokyo Bay, Kagoshima Bay, and Sagami Bay in the Kyushu and Kanto regions, the combination of natural disasters such as typhoons and storm surges, along with rapid urban development and reclamation projects, led to significant coastal loss. Between 1984 and 1994, approximately 290 kilometers of coastline were lost across Japan. In Tokyo Bay and Osaka Bay, more than 70% of wetlands and tidal flats were reclaimed due to industrial zone expansion. In the Ariake Sea, reclamation projects caused ecosystem collapse, reducing migratory bird populations by around 30%. The Environment Agency (now the Ministry of the Environment) and academic institutions began raising concerns about these issues, but concrete conservation measures were limited.

2000s: Full-Scale Coastal Conservation Initiatives

Entering the 2000s, awareness of environmental issues grew, and the "Natural Restoration Promotion Act" was enacted in 2002. This led to nationwide natural recovery projects. In the Ariake Sea, the focus was on restoring tidal flats, addressing ecosystem collapse caused by agricultural runoff and excessive sedimentation by constructing dikes and conducting dredging. These efforts gradually helped recover migratory bird populations. In Sanbanse (Chiba Prefecture), about 1,000 hectares of tidal flats were restored, reviving habitats for birds and aquatic organisms. In Tokyo Bay, the "Green Ring Project" was advanced to restore tidal flats and coastal vegetation. As a result, biodiversity increased by approximately 20% by the late 2000s.

2010s: Addressing Climate Change and Disaster Resilience

In the 2010s, climate change effects became more pronounced, with rising sea levels and abnormal weather accelerating coastal erosion. In areas like Kagoshima Bay and Tokyo Bay, storm surges and typhoon-induced flooding expanded, with the impact area increasing by about 15% compared to the early 2000s. The 2011 Great East Japan Earthquake caused widespread destruction along the Sanriku coastline. In response, strengthening disaster prevention infrastructure, such as seawalls, became a nationwide priority. Approximately 500 kilometers of seawalls were constructed as part of the reconstruction plan, with a budget exceeding 3 trillion yen. Coastal vegetation recovery projects in Tokyo Bay and Sagami Bay increased the area of protected beaches by about 25% over 10 years.

2020s: Sustainable Coastal Management and International Collaboration

In the 2020s, efforts to achieve the Sustainable Development Goals (SDGs) intensified. At COP26, nature-based solutions were emphasized as key to climate change response, and Japan initiated the "Blue Carbon Project" led by the Ministry of the Environment. This project focuses on restoring seagrass beds and coral reefs to enhance carbon absorption capacity. In Tokyo Bay, Seto Inland Sea, and Nagasaki Bay, ongoing activities are expected to absorb approximately 100,000 tons of CO2 annually.

Additionally, the advancement of "smart coastal conservation" utilizing technologies such as drones and AI is underway. Projects involving Kajima Corporation and Takenaka Corporation monitor erosion in real time, allowing precision conservation based on detailed data. This technological implementation is projected to reduce coastal conservation costs by about 30%. Furthermore, in Minami-Boso (Chiba Prefecture) and the Shonan region (Kanagawa Prefecture), collaborative efforts between local residents and companies have promoted beach cleaning and vegetation recovery projects, with resident participation increasing yearly.

Thus, from the 1990s to the 2020s, efforts to address coastal erosion and natural recovery have advanced, particularly in Kyushu and Kanto, with statistical evidence showing the recovery of ecosystems and natural environments.