This sums it up from the article:
“If there is a war, there is no way the U.S. can prevent massive damage to South Korea and significant damage to Japan,” Vasily Kashin, a senior fellow at the Center for Comprehensive European and International Studies at Moscow’s Higher School of Economics told The National Interest. “It would be a humanitarian disaster and a shock for global economy. There are some 24 to 25 nuclear power plant reactors in the South. The North has these hundreds of missiles which are hard to stop.”
Indeed, Pyongyang’s missiles could hit most of Korea and Japan—and it is possible that North Korea might have enough weapons to saturate U.S. and allied missile defenses. “2000 SRBM launchers—that includes KN-02, Scud and the Nodong,” Jeffrey Lewis, Director of the East Asia Nonproliferation Program at the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies at Monterey told The National Interest. “That means several hundred Scud and Nodongs.”