Context: The 2019 Yearbook of the Stockholm International Peace Research Institute (SIPRI), which is part-funded by the Swedish government, was recently released.

Key findings:

• Worldwide total of nuclear warheads has decreased since 2018 but countries are modernising their nuclear arsenals.
• Nine nuclear-armed countries (including India) had a total of some 13,865 nuclear weapons at the start of 2019, which is a decrease of 600 nuclear weapons from 14,465 at the start of 2018
• The report separately counts “deployed warheads” (warheads placed on missiles or located on bases with operational forces) and “other warheads” (stored or reserve warheads and retired warheads awaiting dismantlement). For India, it gives a figure of 130-140 “other warheads” in 2019, the same as in 2018.
• The decrease is mainly attributed to Russia and the US—which together still account for over 90 per cent of all nuclear weapons—further reducing their strategic nuclear forces pursuant to the implementation of the 2010 Treaty on Measures for the Further Reduction and Limitation of Strategic Offensive Arms (New START) while also making unilateral reductions.
• However, both Russia and the US have extensive and expensive programmes under way to replace and modernize their nuclear warheads, missile and aircraft delivery systems, and nuclear weapon production facilities.

• Stockholm International Peace Research Institute:

  Stockholm International Peace Research Institute (SIPRI) established in 1966 is an independent international institute dedicated to research into conflict, armaments, arms control and disarmament.

  Based in Stockholm the Institute provides data, analysis and recommendations, based on open sources, to policymakers, researchers, media and the interested public.

  About New START (Strategic Arms Reduction Treaty):

  It is a nuclear arms reduction treaty between the United States and the Russian Federation with the formal name of Measures for the Further Reduction and Limitation of Strategic Offensive Arms.

  It was signed on 8 April 2010 in Prague, and, after ratification entered into force on 5 February 2011.

  New START replaced the Treaty of Moscow (SORT), which was due to expire in December 2012. Its name is a follow-up to the START I treaty, which expired in December 2009, the proposed START II treaty, which never entered into force, and the START III treaty, for which negotiations were never concluded.

  Under terms of the treaty:

• The number of strategic nuclear missile launchers will be reduced by half.
• A new inspection and verification regime will be established, replacing the SORT mechanism.
• The number of deployed strategic nuclear warheads is limited to 1,550, which is down nearly two-thirds from the original START treaty, as well as 10% lower than the deployed strategic warhead limit of the 2002 Moscow Treaty.
• It will also limit the number of deployed and non-deployed inter-continental ballistic missile (ICBM) launchers, submarine-launched ballistic missile (SLBM) launchers, and heavy bombers equipped for nuclear armaments to 800. The number of deployed ICBMs, SLBMs, and heavy bombers equipped for nuclear armaments is limited to 700.

• Timeline to meet these Targets:

  These obligations must be met within seven years from the date the treaty enters into force. The treaty will last ten years, with an option to renew it for up to five years upon agreement of both parties.