Kristensen is the director of the Nuclear Information Project with the Federation of American Scientists (FAS) in Washington, DC. His work focuses on researching and writing about the status of nuclear weapons and the policies that direct them. Kristensen is a co-author to the world nuclear forces overview in the SIPRI Yearbook (Oxford University Press) and a frequent adviser to the news media on nuclear weapons policy and operations. He has co-authored Nuclear Notebook since 2001.
The Nuclear Notebook is researched and written by Hans M. Kristensen, director of the Nuclear Information Project with the Federation of American Scientists, and Robert S. Norris, a senior fellow with the FAS.
The US nuclear arsenal remained roughly unchanged in the last year, with the Defense Department maintaining an estimated stockpile of some 4,000 warheads to be delivered via ballistic missiles and aircraft. Most of these warheads are not deployed but stored, and many are destined to be retired.
During the Cold War, the United States deployed nuclear weapons in South Korea continuously for 33 years, from 1958 to 1991. The South Korean-based nuclear arsenal peaked at an all-time high of approximately 950 warheads in 1967.
The authors estimate that as of mid-2017, there are nearly 15,000 nuclear weapons in the world, located at some 107 sites in 14 countries. Roughly, 9400 of these weapons are in military arsenals; the remaining weapons are retired and awaiting dismantlement.
India continues to modernize its nuclear arsenal, with at least four new weapon systems now under development to complement or replace existing nuclear-capable aircraft, land-based delivery systems, and sea-based systems.
Hans M. KristensenMatthew McKinzieTheodore A. Postol
The combination of a lack of Russian situational awareness, dangerously short warning times, high-readiness alert postures, and the increasing US strike capacity resulting from a new fuzing system for submarine-based nuclear missiles has created a deeply destabilizing and dangerous strategic nuclear situation.
The US nuclear arsenal remained roughly unchanged in the last year, with the Defense Department maintaining an estimated stockpile of some 4,480 warheads to be delivered via ballistic missiles and aircraft.