The number of nuclear weapons in the world has declined significantly since the Cold War: down from a peak of approximately 70,300 in 1986 to an estimated 14,900 in early-2017.
Government officials often portray that accomplishment as a result of current arms control agreements, but the overwhelming portion of the reduction happened in the 1990s. Moreover, comparing today’s inventory with that of the 1950s is like comparing apples and oranges; today’s forces are vastly more capable. The pace of reduction has slowed significantly. Instead of planning for nuclear disarmament, the nuclear-armed states appear to plan to retain large arsenals for the indefinite future.
Despite progress in reducing Cold War nuclear arsenals, the world’s combined inventory of nuclear warheads remains at a very high level: approximately 14,900 warheads as of early-2017. Of these, roughly 9,400 are in the military stockpiles (the rest are awaiting dismantlement), of which more than 3,900 warheads are deployed with operational forces, of which nearly 1,800 US, Russian, British and French warheads are on high alert, ready for use on short notice.
Approximately 93 percent of all nuclear warheads are owned by Russia and the United States who each have roughly 4,000-4,500 warheads in their military stockpiles; no other nuclear-armed state sees a need for more than a few hundred nuclear weapons for national security:
The United States, Russia and the United Kingdom are reducing their warhead inventories, but the pace of reduction is slowing compared with the past 25 years. France and Israel have relatively stable inventories, while China, Pakistan, India and North Korea are increasing their warhead inventories.
All the nuclear weapon states continue to modernize their remaining nuclear forces and appear committed to retaining nuclear weapons for the indefinite future. For an overview of global modernization programs, see this 2014 article.