The government's fiscal 2007 white paper on disaster prevention notes recent changes in patterns of natural disasters. It cites the Intergovernmental Panel on Climate Change's prediction that global warming will lead to more episodes of heavy rain and more intense tropical cyclones. In 1997-2006, Japan saw 3,132 torrential rain events (hourly precipitation of at least 50 mm) — 1.6 times more than in the previous decade. Events in which hourly precipitation was at least 100 mm numbered 51 — 2.3 times more. A record 12 people died in tornadoes last year. A big earthquake, including one beneath the Tokyo metropolitan area, could happen anytime. In March of this year, for example, the Noto Peninsula in Ishikawa Prefecture was hit by an unexpected major quake.

The white paper warns that social factors are making Japan and the Japanese more vulnerable to natural disasters. In Tokyo, the number of buildings with basements, which are likely to be affected by floods, have doubled in the past 20 years. Three wards in Tokyo's central area have seen the number of high-rise buildings (height of 100 meters or more) increase fourfold in the past 15 years. If lifelines are cut by big quakes, people in these buildings will suffer greatly.

The number of elderly people living alone have almost doubled in the past decade to 4 million. The white paper notes that it will become important to work out special rescue measures for them in the event of a disaster. It also says that the shrinking size of families is hindering the ability of families to help their own as well as other people during a disaster.