This map shows how far North Korea's nuclear missile program has come, and how much work remains to dismantle it

The process of "denuclearizing" the Korean Peninsula is going to take a lot more than the hopeful promises President Donald Trump and North Korean leader Kim Jong Un agreed to at the Singapore summit on Tuesday.

A map of the nuclear arsenal Kim has built up in the just the last few years shows just how hard the challenge will be, thanks to the size and variety of missiles and launch sites.

Both leaders claimed success at the widely watched summit. But their agreement omitted many of the most critical details, including the fate of North Korea's recently developed long-range missile capabilities.

After more than three decades of development, North Korea has an impressive arsenal, according to a database of test flights since April 1984 recorded by the James Martin Center for Nonproliferation Studies.

Until recently, the focus of efforts to contain North Korea's nuclear threat centered on halting further development of Pyonyang's ability to deliver a nuclear warhead over long distances.

But a flurry of successful missile tests in the last few years gave new urgency to the U.S.-led effort to eliminate North Korea's nuclear weapons infrastructure and led to the historic summit between Trump and Kim.

Since Kim's grandfather, Kim Il-sung, first established a missile test site in 1984, North Korea's long-range missile development has come in fits and starts.

Missile testing paused for four years after Kim Jong Il succeeded his father in 1994, and then picked up again in 1998 with a high-profile launch that prompted the Clinton administration to hold talks with North Korea that resulted in a missile testing moratorium. In 2006, North Korea resumed missile testing with another 15 launches over the next three years.

Testing began again in 2011 after Kim Jong Un assumed power and picked up substantially in 2014, when missile launches became much more frequent and used test sites in a number of new locations. Since 2011, Kim has fired more than 90 missiles and conducted four nuclear weapons tests, according to the database. That's more than all the tests conducted during the years his father and grandfather were in power.

The latest burst of testing ended with the successful launch of an intercontinental ballistic missile that many weapons analysts believe could reach anywhere in the Unites States.

Negotiating the details

The president on Tuesday said Secretary of State Mike Pompeo and national security advisor John Bolton will lead detailed negotiations over disarmament. But it's far from clear where those discussions will take place or what the agenda will be.

That process could take years, some disarmament experts believe.

"I do think that a deal is possible but also that it will be a long time before we see the DPRK fully eliminate its nuclear and missile capabilities," said Frank N. von Hippel, senior research physicist and professor of public and international affairs, emeritus, at Princeton University's Program on Science and Global Security.

Last month, North Korea invited international media to witness the destruction of tunnels to a site where it carried out nuclear tests. But some experts have warned that it remains to be seen whether the site was permanently destroyed.

Eliminating North Korea's missile capabilities could be an even thornier task. For one thing, there are many more launch sites. And some smaller missiles can be launched from submarines or from mobile platforms that can be more easily hidden.

"The two sides still need to agree on principles of disarmament, a timetable for implementation, and stringent verification measures -- or put another way, all the hard work remains to be done," YJ Fischer, former assistant coordinator for Iran nuclear implementation at the State Department, told CNBC.

WATCH: Singapore summit: Here's what happened