On April 2 2009, the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) reported the results of examination of the storm surge flooding and the current defence capacity in the Tokyo Bay coastal area against flood tide at an expert panel on large-scale flood control measures of the central disaster management council. In its report, MLIT set up six scenarios based on objects because storm surge flooding may differ according to strength of typhoon, tide condition and so on. In addition, three of the six scenarios have been prepared to examine the influences of the sea level rise caused by global warming:

  1. Case in which a strong typhoon like Typhoon Vera in 1959 (Isewan Typhoon) would attack the Tokyo Bay coastal area and the current shore protection facilities would deal with it in the higher average sea level because of global warming (based on the IPCC Fourth Assessment Report in 2007).
  2. Case in which a super typhoon like Muroto Typhoon in 1934 would attack the Tokyo Bay coastal area and the current shore protection facilities would deal with it in the higher average sea level because of global warming (based on the IPCC Fourth Assessment Report in 2007).
  3. Case in which a super typhoon like Muroto Typhoon in 1934 would attack the Tokyo Bay coastal area, and water gates and embankments at the zero-metre area would be damaged by floating things (based on the IPCC Fourth Assessment Report in 2007).

In terms of maximum flooded areas, 16,105 hectares would be flooded for the first case; 24,619 hectares for the second case and 27,630 hectares for the third case. Then, concerning the maximum volume of flooded water, it would be 102,645,000 cubic metres for the first case; 265,492,000 cubic metres for the second case and 324,365,000 cubic metres for the third case. The report does not examine how many casualties would be because of these flood disasters. However, it is expected in the worst case that some areas such as some parts of Koto Ward in Tokyo (e.g. the Koto Ward office), Chiba city (e.g. the town hall of Chiba city), Funabashi city (e.g. the town hall of Funabashi city) and Yokohama city (e.g. Yokohama station of Japan Railways) would be flooded by 2 to 5 metres in depth at the maximum. Because these areas are overpopulated (448,325 in Koto Ward, 949,730 in Chiba city, 594,298 in Funabashi city and 3,654,429 in Yokohama city), it might be easily expected that the number of casualties would not be small.

As Japan is surrounded by the sea, ‘how to cope with problems related to sea level rise caused by global warming’ is one of the significant issues in the Japan’s adaptation strategies for global warming. However, it seems that both the Japanese Government and Japanese people have been less concerned about how to adapt to sea level rise and even sea level rise itself partly because it is not perfectly certain that the sea level would rise because of global warming and partly because if it were so it would happen in the future, not now. The world might have been obsessed with the current economic recession and less interested in global warming. Surely, our life and happiness would be important. However, it might be necessary to always consider those of the future generations. The future generations would have to live in and cope with the changed world because of global warming caused by the past and present generations. Thus, it can be suggested that the Government of every nation, especially advanced nations, has to spend money for the economic recovery into adaptation measures, making both generations happier. It is our responsibility.

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