As the invasion of Ukraine began on Thursday, Russian president Vladimir Putin reminded the world of his country’s nuclear arsenal.

       “Whoever tries to impede us, let alone create threats for our country and its people, must know that the Russian response will be immediate and lead to the consequences you have never seen in history,” he said during remarks from Moscow.

       “No one should have any doubts that a direct attack on our country will lead to the destruction and horrible consequences for any potential aggressor,” he added, emphasising that Russia is “one of the most potent nuclear powers and also has a certain edge in a range of state-of-the-art weapons”.

       Thus far, Ukraine has said it wants peace and will only fight to defend itself. The US and other powers have committed to harsh sanctions on Russia but not sending in their own troops.

       Still, with such a stark warning, it’s worth asking: What is Russia’s nuclear capacity?

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       Although Russia has drastically reduced its nuclear weapons stores since the Cold War, it still maintains the largest stockpile of nuclear warheads in the world.

       As of 2022, Russia had about 4,447 warheads, 1,588 of which are deployed on ballistic missiles and heavy bomber bases, with another roughly 977 strategic warheads and 1,912 nonstrategic warheads in reserve, according to the Bulletin of the Atomic Scientists.

       Ukraine also inherited a large number of nuclear weapons after the collapse of the Soviet Union in 1991, but the country decided to fully de-nuclearise under the 1994 Budapest Memorandum, which offered the country security assurances from the US, UK, and Russia.

       Thus far, Russia has deployed some “dual-capable” vehicles that could theoretically launch nuclear weapons near Ukraine, but there are no signs on the ground the country has actually deployed nuclear weapons or nuclear custodial units, according to the group. And Russia itself has not announced any plans to use nuclear weapons.

       In 2018, the Trump administration’s Nuclear Posture Review found that “Russian strategy and doctrine emphasize the potential coercive and military uses of nuclear weapons. It mistakenly assesses that the threat of nuclear escalation or actual first use of nuclear weapons would serve to ‘de-escalate’ a conflict on terms favorable to Russia.”

       Russia, meanwhile, has emphasised that it considers its nuclear weapons “exclusively as a means of deterrence”.

       Even without the threat of nuclear war, the invasion of Ukraine could have devastating consequences.

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       At least 150,000 Russian troops are waiting on the border in a state of advanced readiness, according to US defence officials, and Ukrainian president Volodymyr Zelenskyy has warned that, “Any provocation, any spark could trigger a blaze that will destroy everything.”

       Up to 50,000 people could be killed or wounded in a large-scale invasion, and roughly 5 million people could become refugees, according to US intelligence estimates.