We've been hearing a lot about a possible nuclear (and/or Twitter) war with North Korea, which sounds terrifying and, more importantly, completely unnecessary. The talk has been hitting a fever pitch of late because the tiny, eccentric nation has been conducting successful nuclear tests and the US electorate rolled the dice and elected a madman with no impulse control to oversee our nuclear arsenal. NK's first successful test was in 2006 and for a while we were all all clinging to the fact that, in order to actually launch a nuke, they would need a nuclear warhead small enough to fit on a missile, something they hadn't yet done. North Korea says it has conducted five successful nuclear tests - in 2006, 2009, 2013 and two in 2016 - but they aren't yet considered a nuclear powerhouse because the estimated small size of their arsenal is quite small. Which led us to wonder...
Actually, not many. There are about 15,000 nuclear weapons in the world, with the largest stockpiles located in the formerly Cold-Warring Russia and the United States. The rest are spread among seven other nations according the Federation of American Scientists:
The US bombings of Nagasaki and Hiroshima during World War II were the only times nuclear weapons have ever been used as actual weapons of war, and the results were horrifying. The world thought it was really bad if everyone started to stockpile nukes so in 1968, the Treaty on the Nonproliferation of Nuclear Weapons (the NPT) was created to prevent the spread of nuclear weapons and further the goal of nuclear disarmament. The only nations who haven't signed the treaty are India, Israel, Pakistan, and South Sudan. North Korea had signed it but withdrew in 2003. Classic NK.
When NPT was first signed, the US and Russia had nuclear stockpiles in the tens of thousands, but have since collaborated to reduce their arsenals. As of now, the recognized nuclear weapon states (NWS) - those that are recognized as possessing nuclear weapons by the NPT - are the US, UK, Russia, China, and France.