90 seconds to midnight. Things you need to know about nuclear war and its ramifications

Why does the world need nuclear weapons?

Since the American nuclear strikes on Hiroshima and Nagasaki in 1945, nuclear weapons are believed to have played a deterrent role in international relations, preventing a direct military clash between members of the nuclear club and thus foreclosing the possibility of a new world war. In the bipolar world of the Cold War era, the concept of deterrence defined relations between the two superpowers: the Soviet Union and the United States. Deterrence is based on the notions of mutual assured destruction (MAD) and nuclear parity: the approximate equality of nuclear potentials and the inevitable response in the event of a first strike make the conflict pointless (at least in theory), since both sides would simply end up destroying each other.

Nuclear parity is generally maintained today: Russia and the United States possess almost the same number of deployed nuclear warheads for strategic carriers, although when it comes to tactical-class warheads, the Russian stockpile is much larger. In addition, the architecture of existing air and missile defense areas in Russia and the United States is believed to provide sufficient protection for political decision-making centers — and for the nuclear-tipped missile launch positions under their command — to respond in the event of an attack. In other words, in the event of a nuclear war, both countries would have ample time and opportunity to use their entire arsenal to retaliate.

One has to admit, however, that nuclear weapons have not made the planet a safe place: during the Cold War, the confrontation between the superpowers took other forms, with numerous localized proxy conflicts breaking out in remote regions. Furthermore, today the concept of deterrence does nothing to thwart new threats like cyberattacks or disinformation campaigns.

How many times have nuclear weapons been used?

Combat use of nuclear weapons, as we know, occurred only twice: on Aug. 6 and Aug. 9, 1945, when American forces dropped nuclear bombs on the Japanese cities of Hiroshima and Nagasaki.

As for test explosions, there have been more than 2,000 since Jul. 16, 1945: 1,030 of them were conducted by the United States and 715 by the Soviet Union. In the 21st century, North Korea remains the only country conducting nuclear tests.