Construction of the replacement facility in Okinawa for U.S. Marine Corps Air Station Futenma will take nearly twice as long and cost three times as much as the initial estimates. This makes it certain that shutting down Futenma will now be delayed into the 2030s at the earliest — well over three decades after the Japanese and U.S. governments agreed in 1996 on the return of the base site to Japan on condition that a substitute airfield be built elsewhere in Okinawa.

The government needs to reconsider whether building the replacement facility in the Henoko area of Nago — in defiance of persistent opposition by the prefectural government and Okinawa voters — is indeed the quickest path to removing the dangers posed by the Futenma base, located in the middle of the city of Ginowan.

The government confirmed last week that completing the new airfield on a reclaimed site on the Henoko coast will take another 12 years. Underlying this change, the reclamation and construction work is now estimated to take more than nine years, up from the initial estimate of five years, due to additional work to improve the soft ground on the seafloor in the site's offshore areas — which was found in a boring survey three years ago. The entire cost of the project will balloon from the initial forecast of ¥350 billion to ¥930 billion.