Sunday was the first anniversary of the 9.0 earthquake off the east coast of Japan that produced the 45-foot-high tidal wave that hit Fukushima Prefecture.

Twenty thousand perished. Hundreds of thousands were driven from their homes when a nuclear plant swept by the tsunami exploded, spewing radiation for miles.

Only two of Japan’s 54 nuclear plants are now operating. The rest have shut down for inspections. Many may never start up again.

In loss of life, that earthquake-tsunami was seven times as lethal as 9/11. But recovery from that greatest disaster in decades is not the gravest problem facing Japan.

The gravest problem facing the Land of the Rising Sun is that it is dying. The sun that set on the Japanese Empire in 1945 has begun to set on the Japanese nation.

A week before the anniversary of 3/11, buried in a story about Prime Minister Yoshihiko Noda’s effort to rally support for a doubling of the 5 percent consumption tax, to preserve Japan’s social security system, was this startling statement:

“We’re faced with an aging society and a declining birth rate unprecedented in the history of mankind.”

What makes this admission remarkable is that the Japanese are not given to hyperbole, and the prime minister’s statement is rooted in numbers that may fairly be called a demography of death.

Deep inside the story on the Noda tax proposal was this item: “By 2055, according to government data, 40 percent of the country’s population will be 65 or older. Just 8 percent will be younger than 15.”

If accurate, these numbers reveal a deepening of the crisis of demography facing Japan since the population projections of the United Nations came out in 2008.

According to those U.N. figures, where Japan’s population would reach 127 million in 2010, the number of Japanese will shrink to just above 101 million by 2050. Every year between now and 2050, the number of deaths over births in Japan will average two-thirds of a million, with the population shrinkage accelerating each decade.

The median age of a Japanese, 22 years old in 1950, reached 45 in 2010 and will exceed 55 by midcentury. The oldest people on the planet are getting older.

What kind of future can there be for a nation, even one with the high quality human capital of Japan, when there are two Japanese 65 years old or older for every Japanese 24 years of age or younger?