The following is a translation of the Henshu Techo column from The Yomiuri Shimbun's June 6 issue.
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About 100,000 years ago, the Earth was in an interglacial period before the latest ice age, and mankind was coexisting with mammoths. What will the world be like 100,000 years from now?
In Finland, construction is under way to build a nuclear waste repository, where high-level radioactive waste from nuclear power plants will be buried at a depth of 500 meters.
The repository is designed to store the radioactive waste long enough for radioactivity to fall to safe levels. It will have an estimated service life of 100,000 years.
This nuclear waste bunker is the subject of the recently released documentary film "Into Eternity."
In the film, scientists debate the project, some saying that although a record of the bunker will be archived, people 100,000 years from now may not be able to read it. One suggestion is to leave images or symbols to warn future archeologists who may try to excavate the bunker. Others argue that by that time glaciers may cover the site.
In Japan, radioactive waste will be combined with a special glass and solidified in a process called vitrification and cooled inside a special facility for a period of 30 to 50 years. After that, it will be buried in a stable stratum at least 300 meters deep. It is said this process will ensure the waste is stored safely, but the final disposal site has yet to be decided.
What the world will be like 100,000 years from now is beyond human imagination. Nevertheless, we have to set matters right beforehand. That is what "civilizations" do.